Breast Cancer Causes and Prevention Strategies

The website of the New Zealand National Screening Unit includes the following information about risk factors for breast cancer:

“What causes breast cancer?

“Exactly why breast cancer develops in a particular woman is not clear. Breast cancer seems to be linked to hormones, especially the female hormone oestrogen. However, it is unlikely there is one single cause. A combination of factors, some known but others unknown, may trigger or promote the cancer.

“Risk factors and protective factors

“At present there are no certain ways of preventing breast cancer although there are some clues – known as risk factors and protective factors – about who is more likely or less likely to develop the disease. Many of these risk factors are linked to female hormones, especially oestrogen, for example, age at puberty, age at first pregnancy and age at menopause. Many risk and protective factors are uncertain or controversial.

“The risk factors for DCIS appear to be similar to those for invasive breast cancer.

“Most studies of risk factors have been done in women of European background, and risk factors may differ for women of different ethnicities.

“The risk factors listed below are common among women, but there is little they can do about most of them. Some relate to our lives many years before. A few risk factors provide the opportunity to reduce risk by making changes in our lives, but even making those changes cannot give a guarantee.

“Women who have the key risk factors should discuss this with their doctor who can advise them and, if necessary, develop a plan for regular checks that may include mammograms.

“Factors that increase the risk of breast cancer

“Key risk factors

Growing older
Previous breast cancer
Previous breast biopsy showing a condition that increases risk
Strong family history
Inherited genetic factors
Exposure to repeated or high-dose radiation.

“Less important risk factors

Obesity
Weight gain after 18
Current drinking of alcohol
Never had children
First child after 35
Hormone replacement therapy
Oral contraceptives
Depo-Provera contraceptive injection
Ovarian cancer
Being a twin.

“No clear evidence*

High-fat, red meat diet
Environmental chemicals, such as pesticides
Heavy smoking and passive smoking
Use of statins – medicines to control cholesterol.
(*No clear evidence means that the results of studies have been mixed, or there is not enough evidence to say that it is proven.)

“No evidence

Electric blankets
Hair colouring
Abortion or miscarriage
Tea or coffee
Underwire bras
Bruise or injury to the breast
Personality type
Stress
Cellphones, digital clocks, microwaves.

“Factors that are protective

“Protective factors

Menstruation starts at late age
Menopause occurs at a young age
First child at a young age
Having children, the more children the greater the protection
Breastfeeding.

“No clear evidence*

Low fat, high-fibre diet
Phyto-oestrogens – plant oestrogens
Exercise
Green tea
Regular use of non-steroidal anti-inflammatory drugs.”
http://nsu.govt.nz/current-nsu-programmes/2249.asp

I think that the National Screening Unit is to be commended for giving women information about the “Key Risk Factors” and “Less Important Risk Factors”.  It is also good that the organisation has as acknowledged under the “No clear evidence” category those factors which may contribute to breast cancer risk, but which the organisation considers the evidence from studies is mixed, or not strong enough to consider that a risk is proven.

However I am concerned that under the category “No evidence” that the NSU has listed a number of risk factors that have been shown associated with increased breast cancer risk in a number of studies.

Electric blankets and breast cancer risk

The National Screening Unit states that there is “No evidence” that using electric blankets increases breast cancer risk.  This is untrue.  Electric blankets (and other sources of electromagnetic radiation) can increase breast cancer risk.  New Zealand scientist Dr Neil Cherry  (sadly deceased) reported in detail on the of electromagnetic fields and cancer in a paper titled “Electromagnetic Radiation Causes Cancer: The Implications for Breast Cancer” at the World Conference on Breast Cancer in Canada in 1999.  The PDF may be downloaded at this link:
http://www.neilcherry.com/documents/90_s3_EMR-EMF_and_BREAST_Cancer.pdf

The following two links are to studies that show an association between electric blanket use and increased breast cancer risk.  (There are also studies that do not show a link.)

http://www.aje.oxfordjournals.org/content/158/8/798.abstract

http://www.ncbi.nlm.nih.gov/pubmed/1862801

If you have an electric blanket, it should only be used to heat the bed prior to getting into bed. It should then be switched off and unplugged at the wall.  Waterbeds with heating elements may also produce electromagnetic fields that increase breast cancer risk.  Their use is probably best avoided.

Hair dye and breast cancer risk

While the NSU has classified hair dye as being in the “No evidence” category as far as breast cancer risk is concerned there are in fact a number of studies that show increased risk of breast cancer and hair dye, both for women who are occupationally exposed to dyes as well as women who dye their hair.  Using hair dye is also associated with higher risk of some other types of cancer including non-Hodgkins lymphoma. (Confounding the picture is that fact that there are also studies that do not show an association between hair dye and breast cancer.)  What is undeniable is the fact that many hair dyes contain chemicals that are proven carcinogens.

If you dye your hair you can check whether it contains carcinogenic ingredients by checking the ingredient list against the list on this site.
http://www.preventcancer.com/consumers/cosmetics/Tables_cospcp.htm

You can check on whether your hair dye or other personal care or cosmetic products you may use contains hazardous ingredients by typing  the ingredients into the search engine at http://www.cosmeticsdatabase.com/ .  This database includes information about carcinogenicity as well as other hazards such as neurotoxicity.

A good introduction to carcinogens and cancer prevention can be obtained by visiting the website of the Cancer Prevention Coalition.
http://www.preventcancer.com/.  At the following link on their site http://www.preventcancer.com/publications/ you can download a free short (66 page) e-book produced for the the organisation’s Stop Cancer Before It Starts Campaign which deals with the politics of cancer prevention.  (The e-book is at the bottom of the page and can be obtained by clicking on the link “Stop Cancer”.)

For most women, hair dye is an entirely avoidable risk factor for breast and other cancers. (Henna which is a botanical product and hydrogen peroxide are safer alternatives to standard hair dyes.  It is important to check labels even on health food store products as some brands may  contain undesirable ingredients.  There can be reactions between different hair products.  If you are switching from chemical dyes to henna or hydrogen peroxide, consult someone knowledgeable so that you avoid inadvertently damaging your hair.)

Abortion and breast cancer risk

The NSU states that there is “No evidence” that abortion or miscarriage increases breast cancer risk.  This is incorrect.  There have been numerous studies that show increased risk of breast cancer in women with a history of induced abortion.  Miscarriage, especially before a first  full term pregnancy has been also associated with some increase in breast cancer risk.  There have also been studies that have not shown an increased risk of breast cancer for women who have had induced abortions or miscarriages.  The risk is controversial but appears to be real nonetheless. There certainly is not “No evidence”.

The following links include information on this issue:

http://www.lifeissues.net/writers/kah/kah_07chap2overview1.html

http://www.lifeissues.net/writers/kah/kah_07chap2overview1.html#b6

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1060338/

http://www.ids-healthcare.com/Common/Paper/Paper_171/Induced%20Abortion%20as%20an%20Independent%20Risk%20Factor%20for%20Breast%20Cancer.htm (link)

The following link is for a charity that has been set up to publicise the link between breast cancer and abortion.

http://www.abortionbreastcancer.com/

More information can be found by googling abortion + breast cancer.

Obviously if you have had an induced abortion (for whatever reason) or have had a miscarriage, these are risks that cannot now be changed. However, the current denial about the link between abortion and breast cancer is not helpful.  It is important for women to know about this risk as part of making an informed decision if they are considering abortion for an unwanted pregnancy (as well as other risks associated with induced abortion such as the possibility of infection, haemorrhage and the potential for subsequent pregnancies to be put at risk through increased risk of miscarriage, premature birth etc.) For women who have already had an induced abortion or miscarriage, knowing that they may be at increased risk of breast cancer is important in making decisions about breast cancer screening.

Stress

Stress has been documented to increase the risk of ill health.  The NSU states that there is “no evidence” that stress contributes to breast cancer risk.  This is unfortunately untrue. A number of studies have shown a correlation between stress and increased risk of developing breast cancer, although it is  true that there are also studies that do not show a link.  Major life events, including those that take place in childhood such as death of parent or experiencing parental divorce appear to increase breast cancer risk.  Severe stress in adult life (such as death of a spouse) may also increase cancer risk.  Unfortunately stress is often unavoidable.  Stress can be managed, however, and acknowledging the potential for stress to cause bad health allows us to take stock of our situation, make changes to reduce stress and reduce the risk of  developing  stress-related disease.

http://www.ncbi.nlm.nih.gov/pubmed/10883721?dopt=AbstractPlus&holding=f1000,f1000m,isrctn

http://www.ncbi.nlm.nih.gov/pubmed/14601065?dopt=AbstractPlus&holding=f1000,f1000m,isrctn

http://www.ncbi.nlm.nih.gov/pubmed/15582263?dopt=AbstractPlus&holding=f1000,f1000m,isrctn

Further sources of information about breast cancer causes and prevention strategies

http://www.sensible-alternative.com.au/female-hormones/breast-cancer-prevention

This link provides a good overview of breast cancer risk factors and how these may be reduced.

http://www.naturalnews.com/Report_Breast_Cancer_Deception_0.html

This link is the beginning of a report on breast cancer that provides information about the politics of cancer, carcinogens, breast cancer prevention as well as some alternative treatments.

Disclaimer:  Information on this site is provided for informational purposes and is not meant to substitute for the advice provided by your own physician or other health professional.  Readers are urged to think carefully about the risks and benefits of different breast screening options and to seek additional information if necessary.  Inclusion of links to other websites on this site does not imply endorsement of that organisation by BreastScreeningOptions.org nor does it imply endorsement of BreastScreeningOptions.org by any other organisation or company.

General Risks of Breast Screening

Breast screening is not a risk free enterprise.  Even when the test itself is harmless (such as thermography) screening is not risk free.

There are several risks associated with breast screening. These include:

False positive results

False positive results refer to cases in which a screening test such as a mammogram appears to show a problem which further investigations show is not actually present.

False positive results occur reasonably frequently with mammography.  Up to ten percent of women may be called back for further tests, usually more mammograms and/or ultrasound examinations.  Some will be advised to have breast biopsies which have the potential to cause pain at the time of the procedure, and subsequently scarring that may interfere with the ability of radiographers to accurately interpret future mammograms. Some biopsies are x-ray guided which exposes sensitive breast tissue to more potentially carcinogenic radiation.

http://www.womens-health.org.nz/index.php?page=breastscreen-aotearoa

Most women who do have these further tests will be found not to have cancer.

http://www.nsu.govt.nz/current-nsu-programmes/576.asp#What_if_I_have_an_abnormal_result

According to Women’s Health Action’s website:

“Women who are brought back for more tests often naturally worry about what this means, even though the chance of being told they have cancer is only about one in 10.”

http://www.womens-health.org.nz/index.php?page=breastscreen-aotearoa

NB: Biopsy of tumours that are cancerous also carries the theoretical risk that cancer cells that may previous have been enclosed completely within a tumour may be inadvertently spread by the procedure.

Abnormal test results in a mammogram can cause significant anxiety even if it turns out that nothing is wrong.

Women whose thermograms show abnormal results may also suffer anxiety.  They may also be recommended to consult a doctor for advice about further tests (such as mammograms, ultrasound or breast biopsy) if a thermogram shows significant abnormalities, potentially exposing them to the risks described above, should they follow medical advice.

If a thermogram shows a result that is neither wholly normal, nor severely abnormal such as “Th III” – “suspicious but not conclusive”, this may  also cause serious concern.  Further investigations such as mammography may fail to show any sign of cancer.  However, given that according to the American Journal of Surgery (Vol 196, No. 4, October 2008) “38% of the patients of the 1,245 patients with Thermogram Th III (suspicious but not conclusive) developed cancer within 1-4 years of follow up” women who have a Th III rated thermogram may naturally remain apprehensive about their health for some time.

Thermograms that show that a woman appears to be at increased risk of developing breast cancer (in the absence of detectable tumours) represent both the  potential promise and the peril of thermography.  Identifying a possible pre-cancerous condition in the breast can give a woman whose lifestyle has been unbalanced or unhealthy the opportunity to adopt health promotion strategies that may result in an improvement in breast health and prevent further deterioration in breast tissue that could result in breast cancer.  However, for women who are unwilling (or unable) to institute the type of lifestyle changes and/or treatments that have been successful for other women in similar situations (or for whom these measures do not yield comparable results), an abnormal thermogram may cause chronic anxiety that adversely affects their quality of life, and may also undermine their health.

Women who have had a previously abnormal thermogram may be advised to have repeat thermograms every three or four months, rather than at the one year interval often suggested for routine thermography screening.  Given that the entire cost of this test is borne by the client because there is no government funding for this service, repeat thermograms may cause financial stress for low income earners.

Possible over-diagnosis and over-treatment

According to information on Women’s Health Action’s website, other risks of mammography include:

“Possible over-diagnosis and over-treatment …This means finding and treating conditions which may never have caused a woman problems had they not been detected by screening. Some cancers are slow growing and could be successfully treated later when a lump is felt. Earlier detection may cause additional months or years of cancer-related anxiety.

“Mammography can detect some conditions which are not completely understood. There may be uncertainty about whether they will progress and what the best treatments are. Sometimes the abnormal tissue can be spread through one breast, or even through both breasts. This means that it can only be removed by complete removal of the breast or breasts. Women in this situation sometimes have more extensive surgery than women with invasive cancer. One of the conditions is called ductal carcinoma in situ (DCIS). The screening programme can provide more information on this condition.

“Over-diagnosis and over-treatment are estimated to account for between 0-10% of cancers detected by breast screening [mammography].”

http://www.womens-health.org.nz/index.php?page=breastscreen-aotearoa

The authors of a major recent study of mammography recently stated “our findings simply provide new insight on what is arguably the major harm associated with mammographic screening, namely, the detection and treatment of cancers that would otherwise regress.”

http://archinte.ama-assn.org/cgi/content/full/168/21/2311

Given that conventional cancer treatment is based on a “remove/kill the cancer cells”  philosophy, and that conventional allopathic treatments such as surgery, radiation and chemotherapy entail substantial risks to health, overdiagnosis and treatment of breast cancer has the potential to cause substantial harm.

False negative results

From the Women’s Health Action website:

“False negative results

This means actual cancers are missed. About 10% of invasive breast cancers are not detected by mammography in women 50-59 years. In women 40-49 up to 25% are missed. False negatives can give women false reassurance that cancer is not present and may delay them reporting symptoms to their doctor.”

http://www.womens-health.org.nz/index.php?page=breastscreen-aotearoa

Thermography similarly fails to detect some cases of breast cancer.  A normal thermogram does not exclude the possibility of breast cancer; although it is unlikely that a woman with a normal thermogram has breast cancer. Thermography is less accurate for women who have very large breasts since the thermal signature of a tumour that is located deep in breast tissue may not be detected.  Diffuse cancers that cause oedema or skin thickening may not be detected by thermography. Some breast cancers do not produce an abnormal heat signature and can also be missed by thermography.

http://www.clinicalthermography.co.nz/Site/FAQs.ashx

Even with modern equipment and trained personnel, up to 10% of breast cancers may go undetected by thermography. (International Journal of Thermal Sciences 48 (2009) 849-859).

It is therefore important for women who have recently had a normal mammogram and/or thermogram to realise that neither of these tests (either separately or in combination) are perfect and to seek a medical opinion if they develop any symptoms suggestive of breast cancer. (See the section on Breast Awareness for possible symptoms of breast cancer.)

Other risks

A major risk of any type of screening that focuses on detecting cancer (or pre-cancerous conditions) is that if a test shows no problem, people may assume that they do not need to be concerned about their health, when in fact, they may have many risk factors that could lead to the development of cancer (or another unpleasant disease) later in life – or even in the not too distant future.  In the case of breast cancer these factors may include alcohol intake, lack of exercise, use of potentially carcinogenic medications (such as oral contraceptives, Depo Provera or HRT), nutritional deficiencies etc; see the page Breast Cancer Causes and Prevention Strategies for more information.  (Many of these risk factors also increase the risk of developing cancer of the cervix and cardiovascular disease.)

Ideally, breast health check ups would not only focus on detecting possible cancerous or pre-cancerous conditions of the breast (using mammography and/or thermography and/or clinical breast examination, depending on the individual’s choice) but would include a lifestyle assessment so that any modifiable risk factors that are significantly increasing a woman’s risk of breast cancer could be identified and steps taken to reduce or eliminate these risks when possible, thereby potentially improving general health as well as breast health.   For women who have symptoms associated with problems with oestrogen metabolism (such as bad premenstrual symptoms) tests for oestrogen metabolism may be desirable.

Disclaimer:  Information on this site is provided for informational purposes and is not meant to substitute for the advice provided by your own physician or other health professional.  Readers are urged to think carefully about the risks and benefits of different breast screening options and to seek additional information if necessary.  Inclusion of links to other websites on this site does not imply endorsement of that organisation by BreastScreeningOptions.org nor does it imply endorsement of BreastScreeningOptions.org by any other organisation or company.

Thermography

What does the test involve?

Having a breast thermogram involves sitting topless in front of an infrared camera (operated by a female technician) and changing position every so often so that different areas of the breasts can be imaged.  The technician does not touch the woman’s breast (or any other body parts.) Some thermography providers ask their clients to place their hands in a bowl of icy cold water for a one minute so that differences in blood flow within breast tissue can be observed before and after this “cold challenge” test.  The cold water can be uncomfortable.

Since thermography measures heat being emitted from breast tissue, it is important to avoid activities that may influence the heat of the breasts prior to the thermogram.  Such activities include vigorous exercise within four hours of the thermogram, and no hot drinks within an hour of the thermogram.  Women are also advised not to shave their armpits on the day of the thermogram, nor wear tight fitting clothing such as a bra on the day of their appointment.

http://www.clinicalthermography.co.nz/Site/Your_Appointment/Pre-Appointment_Instructions.ashx

(Thermography providers give their clients a list of written instructions of activities to avoid prior to the thermogram.)

Younger women are advised to schedule their appointment for the first half of their menstrual cycle.  For post menopausal women, thermography can be performed at any time.

What does the test cost?

In NZ, thermography does not receive any sort of government funding, so clients pay the entire cost of the test. The cost of the test varies between providers but is generally around $200.

What are the potential benefits of the test?

Thermography is a test that measures heat emitted from the breasts.  In healthy breasts the pattern of infrared radiation emitted from each breast will be very similar.

http://nzbta.org.nz/index.php?page=about-breast-thermography

Variations in breast temperature detected by thermography can indicate potential problems with breast health.  Significantly elevated temperature readings may indicate the likely presence of a cancerous breast tumour.  Most breast cancers develop a dense network of blood vessels around them as they grow.  It is the heat signature created by the additional blood vessels surrounding most breast cancers that can be detected by thermography.

http://www.clinicalthermography.co.nz/Site/What_is_Thermography/Breast_Thermography.ashx

Women who have a significantly abnormal thermogram are advised to consult their doctor about appropriate follow up testing so that the possibility of breast cancer can be confirmed or excluded.

Thermography potentially offers the chance to detect breast cancers while they at a very early stage of development as cancerous breast tumours begin to develop an enhanced network of blood vessels while they are still so small that they cannot be detected by mammography.

Thermograms that are mildly abnormal may indicate a need to take steps to improve breast health.  Persistently abnormal thermograms are associated with an increased risk of breast cancer.

What are the risks associated with thermography?

1) The risks that apply to breast screening in general also apply to thermography [link to this page here]

2)  Thermography does not involve exposure to radiation so is risk-free in this respect.
(See: NZBTA Thermogaphy Synopsis 2010.pdf, which can be downloaded from  http://nzbta.org.nz/index.php?page=research)

3)  There have not yet been large scale studies that prove that modern thermography screening does actually reduce mortality from breast cancer and the studies that have shown benefits from thermography have been relatively small compared to the studies of mammography.  To the best of my knowledge there have not been any large scale studies to assess the benefits of making lifestyle changes after a thermogram has detected an abnormality.  (There are case histories that show improvement in serial thermograms after lifestyle interventions have been instituted but no organised research in this area.)

How accurate is the test?

When breast thermography is conducted by a trained operator in an appropriate setting (i.e. a room that is at a constant temperature and free from drafts etc) and the results are analysed by computer and reviewed by a doctor with appropriate training, it offers a high degree of accuracy in detecting the variations in breast temperature associated with most breast cancers.

The American Journal of Surgery (Vol 196, No. 4, October 2008) discusses a study in 1980 in which the researchers found that patients with a thermogram rate stage Th IV or V “had a 90% chance of having cancer at the time of the study and more interestingly 38% of the patients of the 1,245 patients with Thermogram Th III (suspicious but not conclusive) developed cancer within 1-4 years of follow up.”  The conclusion to their own study stated that “a modernized DITI system can be a useful adjunct test in detecting breast cancer with 97% sensitivity in this prospective trial of 92 patients.”  (Sensitivity refers to the ability of a test to correctly identify that a patient is suffering from a certain condition.)

According to the International Journal of Thermal Sciences 48 (2009) 849-859:

“International research about thermography shows that the new thermography cameras, combined with analytical software and personnel can offer useful information about breast health.”… “For the last 1.5 decades of complying with the strict standardized thermogram interpretation protocols by proper infrared trained personnel as documented in the literature, breast thermography has achieved an average sensitivity and specificity of 90%.  An abnormal thermogram is reported as the significant biological risk marker for the existence of or continued development of breast tumor.”  (Specificity refers to the ability of a test to correctly identify that healthy people do not have the condition for which they are being tested.)

This means that the false positive rate and false negative rates for modern thermography are similar to that of mammography. In fact, for younger women thermography may be more accurate since breast tissue density does not affect the accuracy of thermography.

Thermography does have limitations as a test.  It is less accurate for women who have very large breasts since the thermal signature of a tumour that is located deep in breast tissue may not be detected.  Diffuse cancers that cause oedema or skin thickening may not be detected by thermography. Some breast cancers do not produce an abnormal heat signature and can also be missed by thermography.  For this reason, thermography providers generally recommend that thermography is used in addition to mammography, rather than as a sole breast screening option.

http://www.clinicalthermography.co.nz/Site/FAQs.ashx

Sources of additional information on thermography

http://www.minnesotamedicine.com/CurrentIssue/CommentaryPlotnikoffDec2009/tabid/3272/Default.aspx

This medical journal article discusses both mammography and thermography.

http://www.nzbta.org.nz/

This is the website of the NZ Breast Thermography Association, an industry association established in 2010 to regulate the breast thermography in NZ.  A summary of the findings of recent medical literature pertaining to breast thermography may be downloaded from the site and a copy of the full research review is available on request.

http://www.clinicalthermography.co.nz/

This is the website of Clinical Thermography Ltd, a company that offers breast thermography at various locations around NZ.  The site includes a considerable amount of information about thermography.

http://safe2scan.com/

This is the website of Safe2Scan Diagnostic Thermography which offers breast thermography in Nelson.

Disclaimer:  Information on this site is provided for informational purposes and is not meant to substitute for the advice provided by your own physician or other health professional.  Readers are urged to think carefully about the risks and benefits of different breast screening options and to seek additional information if necessary.  Inclusion of  links to other websites on this site does not imply endorsement of that organisation by BreastScreeningOptions.org nor does it imply endorsement of BreastScreeningOptions.org by any other organisation or company.

Mammography

What does the test involve?

Mammography involves placing the breasts between two glass plates.  The breasts need to be compressed to reduce the thickness of the tissue through which the x-rays travel.  The breast compression can be uncomfortable or painful.

What does the test cost?

Screening mammography is offered free of charge to most NZ women between the ages of 45 and 69 through a national publicly funded service BreastScreen Aotearoa. The National Breast Screening Unit states that there is “very little benefit” for screening mammography for women aged 70 years and over.  BreastScreen Aotearoa does not offer free mammograms to women younger than 45 because of their denser breast tissue means that the test results are harder to read and more women in this age group may experience false positive results.

http://nsu.govt.nz/current-nsu-programmes/854.asp

Other women who want to have mammograms can obtain a referral from a doctor and pay for the service which costs around $160.

http://www.healthpoint.co.nz/default,32117.sm;jsessionid=16765384DA7B854052A29592ECCA780C

What are the potential benefits of the test?

According to the NZ National Screening Unit, “Studies clearly show that when women aged 50 years and over are invited to have mammograms every two years as part of a screening programme, their risk of death from breast cancer is reduced by about a third. For women aged 45 to 49 years, the risk of death from breast cancer is reduced by about a fifth.”

However, not all studies in the medicial literature show an unequivocal benefit to mammography.

An article in the Journal of the National Cancer Institute in 2000 concluded:

“In women aged 50–59 years, the addition of annual mammography screening to physical examination has no impact on breast cancer mortality.”

http://jnci.oxfordjournals.org/content/92/18/1490.abstract?ijkey=63ee2f9ffdd103e2f7211ae26e5bce47f75b2dc0&keytype2=tf_ipsecsha

A Canadian study in which 50,430 women participated found that mammography was no better than a “single breast physical examination and instruction on breast self examination”.  The objectives of the study were:

“To compare breast cancer mortality in 40- to 49-year-old women who received either 1) screening with annual mammography, breast physical examination, and instruction on breast self-examination on 4 or 5 occasions or 2) community care after a single breast physical examination and instruction on breast self-examination.”

The authors concluded:

“After 11 to 16 years of follow-up, four or five annual screenings with mammography, breast physical examination, and breast self-examination had not reduced breast cancer mortality compared with usual community care after a single breast physical examination and instruction on breast self-examination.”

http://www.annals.org/content/137/5_Part_1/305.abstract?ijkey=0bf2c26131970ac9a88b3d07e1434ff93d4a7e76&keytype2=tf_ipsecsha

What are the risks associated with mammography?

There are a number of risks associated with mammography.

1) First of all there are the risks that apply to breast screening in general (Please refer to the entry “General Risks of Breastscreening”.)

2)  Ionising radiation

Mammography also involves exposure to potentially carcinogenic ionising radiation.  BreastScreen Aotearoa states that the radiation risk from  mammograms is “extremely small”.

The website of Women’s Health Action acknowledges the cancer risk from ionising radiation:

According to the site:

“The radiation risk from modern mammography is extremely low. For a woman attending breast screening every two years from the age of 50 to 64, the possible risk of dying from a breast cancer caused by radiation is estimated to be one in 20,000. For a woman who starts annual mammography at the age of 40, then has it every two years from 50 to 64, there would be one radiation induced breast cancer death per 10,000 women.”

http://www.womens-health.org.nz/index.php?page=breastscreen-aotearoa

However, according to Dr Samuel Epstein, mammography (as practised in the USA) entails substantial cancer risks:

“Radiation from routine mammography poses significant cumulative risks of initiating and promoting breast cancer (1- 3). Contrary to conventional assurances that radiation exposure from mammography is trivial – and similar to that from a chest X-ray or spending one week in Denver, about 1/ 1,000 of a rad (radiation-absorbed dose)- the routine practice of taking four films for each breast results in some 1,000-fold greater exposure, 1 rad, focused on each breast rather than the entire chest (2). Thus, premenopausal women undergoing annual screening over a ten-year period are exposed to a total of about 10 rads for each breast. As emphasized some three decades ago, the premenopausal breast is highly sensitive to radiation, each rad of exposure increasing breast cancer risk by 1 percent, resulting in a cumulative 10 percent increased risk over ten years of premenopausal screening, usually from ages 40 to 50 (4); risks are even greater for “baseline” screening at younger ages, for which there is no evidence of any future relevance. Furthermore, breast cancer risks from mammography are up to fourfold higher for the 1 to 2 percent of women who are silent carriers of the A-T (ataxia-telangiectasia) gene and thus highly sensitive to the carcinogenic effects of radiation (5); by some estimates this accounts for up to 20 percent of all breast cancers annually in the United States (6).”

http://www.preventcancer.com/patients/mammography/ijhs_mammography.htm

Dr Epstein is the author of The Politics of Cancer and has spent the last few decades fighting to reduce the exposure of the American public to carcinogens that are fueling that country’s cancer epidemic.

UPDATE: According to information that I have obtained by making a request under the Official Information Act, for New Zealand women who have mammograms as part of BreastScreen Aotearoa “The average glandular dose [of radiation] must be less that 3mGy (0.3 rad) for a single view of a breast.”  (In the BreastScreen Aotearoa, two views are usually taken of each breast, compared to four views of each breast in the example of the American women cited by Dr Epstein. )  This means that the “average” New Zealand’s woman’s radiation exposure from mammography appears to be lower than that of American women – because BreastScreen Aotearoa offers mammograms on a two yearly (rather than an annual) basis and only two images of each breast are taken at most screening sessions.

3)  False positive results

Other potential risks from mammography include false positive results which can cause significant anxiety.  Biopsy can of suspicious areas of the breast is the only definitive way of determining whether or not a lesion identified on a mammogram does in fact represent cancer or a benign condition.

4) Possible rupture of breast implants

Women who have had breast reconstruction following breast cancer surgery (or for any other reason) should be aware that there is a small risk of the breast implants being ruptured during mammography due to the breast compression involved in this procedure.

“Mammograms require breast compression, which could contribute to implant rupture. According to the FDA adverse event database, there were 41 reported cases of breast implant rupture during mammograms, reported between 1992 and 2002. An additional 17 cases of breast implant rupture during mammograms were reported in the medical literature.

“In addition to special care taken by the radiological technologist to reduce the risk of breast implant rupture during this compression, other techniques are used to maximize what is seen of the breast tissue during mammograms. These techniques are called breast implant displacement views, Eklund displacement views, or Eklund views, named for the radiologist who developed the techniques. These special implant displacement views are done in addition to those views done during routine mammograms.

“Because of the extra views and time needed women with implants should always inform the receptionist or scheduler that they have breast implants when making an appointment for a mammogram. They should also tell the radiological technologist about the presence of implants before a mammogram is performed. Then, the radiological technologist will use these special displacement techniques and take extra care when compressing the breasts to avoid rupturing the breast implant.

“The displacement procedure involves pushing the implant back and pulling the breast tissue into view. Several factors which may affect the success of this special technique, in imaging the breast tissue in women with breast implants, include the location of the implant, the hardness of the capsular contracture and the amount of the breast tissue compared to the implant size.

“Also, when reading the mammogram, the radiologist may find it difficult to distinguish calcium deposits in the scar tissue around the implant from a breast tumor. Occasionally, it is necessary to remove and examine a small amount of tissue (biopsy) to see whether or not it is cancerous. Frequently, this can be done without removing the implant.”

http://www.imaginis.com/breast-health/breast-implant-imaging

How accurate is the test?

The accuracy of mammography depends partly on the age of the woman being screened.

According to Women’s Health Action website, up to 25% of cancers may be missed in younger women.  For older women the test is more accurate. To quote from the site:

“False negative results …This means actual cancers are missed. About 10% of invasive breast cancers are not detected by mammography in women 50-59 years. In women 40-49 up to 25% are missed. False negatives can give women false reassurance that cancer is not present and may delay them reporting symptoms to their doctor.”

Also from this site:

“False positive results … This means a woman is told something is not quite right about her mammogram. She then needs further investigations, usually more mammograms and ultrasound examination. In some cases, a sample of breast cells or tissue is taken. Only a small number of these women will actually have cancer. Up to one in ten women who have mammograms will be brought back for another mammogram or more tests.”

http://www.womens-health.org.nz/index.php?page=breastscreen-aotearoa

For women with breast implants, the interpretation of mammograms is more difficult as calcified scar tissue around the implant has a similar appearance to a breast tumour.

http://www.imaginis.com/breast-health/breast-implant-imaging

Further sources of information about mammography:

http://www.minnesotamedicine.com/CurrentIssue/CommentaryPlotnikoffDec2009/tabid/3272/Default.aspx

This medical journal article discusses both mammography and thermography

http://www.sensible-alternative.com.au/female-hormones/rethinking-mammograms

This site provides information about mammography as well as well as information about breast health and other women’s health issues.

http://www.womens-health.org.nz/index.php?page=breastscreen-aotearoa#7

This link at the website of Women’s Health Action provides an overview of the risks and benefits of mammography.

http://nsu.govt.nz/current-nsu-programmes/559.asp

This is the link to the site of the National Screening Unit, which runs BreastScreen Aotearoa

Disclaimer:  Information on this site is provided for informational purposes and is not meant to substitute for the advice provided by your own physician or other health professional.  Readers are urged to think carefully about the risks and benefits of different breast screening options and to seek additional information if necessary.  Inclusion of links to other websites on this site does not imply endorsement of that organisation by BreastScreeningOptions.org nor does it imply endorsement of BreastScreeningOptions.org by any other organisation or company.

Breast Awareness

The NZ National Screening Unit gives the following advice to women on the subject of breast awareness:

“Some cancers are found by the woman herself or her partner. You can help find breast cancer early by getting to know your breasts and being aware of any changes that are not normal for you.

“Looking at your breasts in the mirror and feeling them while washing or dressing are important as you get older, especially after age 40. This is recommended for all women, even if they are having mammograms.

“If you notice any breast symptoms (changes that are not normal for you) see your doctor as soon as possible. Do not wait for you next mammogram to have this problem checked. [original emphasis]

“Possible signs of breast cancer are:

a new lump or thickening

a change in breast shape or size

pain in the breast that is unusual

puckering or dimpling of the skin

any change in one nipple, such as:
a turned-in nipple

a discharge that occurs without squeezing

a rash or reddening of the skin that appears only on the breast.”

http://nsu.govt.nz/current-nsu-programmes/2247.asp

The advice to see a doctor if you notice any of the possible signs of breast cancer even if you have recently had  a mammogram – is good advice.  It applies equally to women who have recently had a thermogram or a breast examination by a doctor or nurse that did not reveal any problems.

Disclaimer:  Information on this site is provided for informational purposes and is not meant to substitute for the advice provided by your own physician or other health professional.  Readers are urged to think carefully about the risks and benefits of different breast screening options and to seek additional information if necessary.  Inclusion of  links to other websites on this site does not imply endorsement of that organisation by BreastScreeningOptions.org nor does it imply endorsement of BreastScreeningOptions.org by any other organisation or company.

Breast Screening Options Overview

Currently in NZ, there are a number of options available for women who want to check the health (or otherwise) of their breasts

They include:

*  Breast awareness in which a woman (and/or her husband/partner) becomes familiar with the normal size and shape of her breasts so that if she notices any changes, she can visit a health professional for advice.

*  Annual breast examination with a health professional.  A breast examination by a doctor or specially trained nurse offers a way by which breast cancers may be detected.

*  Mammography which is the use of x-ray radiation to take images of the breasts.  The resulting images are then examined by a radiologist for signs of cancer or other abnormalities.

*  Thermography which is the use of special cameras which record the heat (infrared radiation) which is emitted from the breasts.  The data gathered is then analysed by computer as well as reviewed by a specially trained doctor.

*  MRI:  MRI (Magnetic Resonance Imaging) is a diagnostic tool that uses radiowaves and a powerful magnetic field and can produce very detailed images of the breasts and other parts of the body.  It involves the use of a contrast medium based on salt of an element called gadolinium.   The test is very expensive and not normally used as a screening test for this reason.

Disclaimer:  Information on this site is provided for informational purposes and is not meant to substitute for the advice provided by your own physician or other health professional.  Readers are urged to think carefully about the risks and benefits of different breast screening options and to seek additional information if necessary.  Inclusion of  links to other websites on this site does not imply endorsement of that organisation by BreastScreeningOptions.org nor does it imply endorsement of BreastScreeningOptions.org by any other organisation or company.

What is the average risk of developing breast cancer?

Breast cancer risk rises with age; in NZ over 70% of new cases are among women 50 years and over.

In NZ, the current (as of late 2009)  lifetime risk (for women) for developing breast cancer was 1 in 9.

Http://www.nzbcf.org.nz/component/content/article/9-news/238-breast-cancer-in-new-zealand

In the USA, it is 1 in 8.

http://www.cancer.gov/cancertopics/factsheet/Detection/probability-breast-cancer

In NZ, according to the The New Zealand Breast Cancer Foundation “Breast Health Education Kit 2010:  Risk and Risk Reduction Factors for Breast Cancer February 2010” (downloadable from the NZ Breast Cancer Foundation website), for New Zealand women current average risks of developing breast cancer by decade of age are as follows:

“Age               Risk                      Risk Percent
30s                 1 in 204                (0.5%)
40s                 1 in 67                  (1.5%)
50s                 1 in 35                  (2.8%)
60s                 1 in 33                  (3.0%)
70s                 1 in 38                  (2.6%)”

It appears that the breast cancer risk for NZ women in their 30s, 40s and 50s is higher than for American women in the same age groups. (It is also possible that different techniques are used to determine cancer risk.)

The US National Cancer Institute’s (NCI) Surveillance, Epidemiology, and End Results (SEER) Program has published its SEER Cancer Statistics Review 1975–2007 includes estimates of  the probability of American women being diagnosed over several different decades of their adult lives.

The information below is excerpted from the following website:

http://www.cancer.gov/cancertopics/factsheet/Detection/probability-breast-cancer

“What is the average American woman’s risk of being diagnosed with breast cancer at different ages? The estimated probability of being diagnosed with breast cancer for specific age groups and for specific time periods is generally more informative than lifetime probabilities. Estimates by decade of life are less influenced by changes in life expectancy and incidence rates. The SEER report estimates the risk of developing breast cancer in 10-year age intervals (1). These calculations factor in the proportion of women who live to each age. In other words, they take into account that not all women live to older ages, when breast cancer risk becomes the greatest.

A woman’s chance of being diagnosed with breast cancer is:

“from age 30 through age 39 . . . . . . 0.43 percent (often expressed as “1 in 233”)
“from age 40 through age 49 . . . . . . 1.45 percent (often expressed as “1 in 69”)
“from age 50 through age 59 . . . . . . 2.38 percent (often expressed as “1 in 42”)
“from age 60 through age 69 . . . . . . 3.45 percent (often expressed as “1 in 29”)

“These probabilities are averages for the whole population. An individual woman’s breast cancer risk may be higher or lower, depending on a number of factors, including her family history, reproductive history, race/ethnicity, and other factors that are not yet fully understood.

“To calculate an individual’s estimated risk, see the Breast Cancer Risk Assessment Tool at http://www.cancer.gov/bcrisktool/ on the Internet. For more information on the subject of lifetime risk of breast cancer, see http://surveillance.cancer.gov/statistics/types/lifetime_risk.html on the Internet.

“Selected Reference

Altekruse SF, Kosary CL, Krapcho M, et al. SEER Cancer Statistics Review, 1975–2007. Bethesda, MD: National Cancer Institute, 2010.”

Commentary

The fact that there are no figures for women under 30 for either the NZ or US data does not mean that women in their 20s or teens never get breast cancer.  However it is a rare disease in very young women.   Women older than 80 can also develop breast cancer as well. However, data for these older age groups was not included on the websites from which I excerpted the statistics.

Both the NZ and US figures do give a good idea of how breast cancer incidence rises with age.  However, in each case the figures refer only to “average” risk.  Personal risk can be influenced by many factors, not all of which are included as variables in the Breast Cancer Risk Assessment Tool mentioned above, meaning that the accuracy of the Breast Cancer Risk Assessment Tool is open to question.  (For more information about factors that increase breast cancer risk please see the post: “Breast Cancer Risk Factors and Prevention Strategies”.

Disclaimer:  Information on this site is provided for informational purposes and is not meant to substitute for the advice provided by your own physician or other health professional.  Readers are urged to think carefully about the risks and benefits of different breast screening options and to seek additional information if necessary.  Inclusion of  links to other websites on this site does not imply endorsement of that organisation by BreastScreeningOptions.org nor does it imply endorsement of BreastScreeningOptions.org by any other organisation or company.

Breast cancer in New Zealand:

A brief overview

Breast cancer is a common form of cancer in New Zealand women and is becoming more common:

Information on the Women’s Health Action website (dated December 1998) states:

“Breast cancer is one of the most common cancers in New Zealand. Each year about 1600 women develop breast cancer and about 580 New Zealand women die from the disease.

“The chances of developing breast cancer are similar for Maori and non-Maori women.

“Nearly 10% of New Zealand women will develop breast cancer in their lives; put the other way, over 90% of New Zealand women do not get breast cancer.”

http://www.womens-health.org.nz/index.php?page=breastscreen-aotearoa

According to information on the NZ Breast Cancer Foundation website (dated October 2009):

Breast cancer is the most common cancer among New Zealand women, with more than 2500 new cases expected this year – also approximately 20 men will be diagnosed.

More than 600 women will die from the disease this year – making it the leading cause of cancer-related death in females.
1 in 9 women will be diagnosed with breast cancer during their lifetime.
90-95% of women who are diagnosed with breast cancer have no family history of the disease.”

Http://www.nzbcf.org.nz/component/content/article/9-news/238-breast-cancer-in-new-zealand

What does this information tell us?

Firstly, assuming that projections of  breast cancer incidence are accurate, the number of New Zealand women who are developing breast cancer has increased significantly since the late 1990s.  Thankfully, the breast cancer death rate is not increasing as fast as the incidence rate.

However breast cancer is both the most common form of cancer in NZ women and the most common cause of cancer-related death in NZ women.

Despite the increase in breast cancer incidence, 8 out of 9 New Zealand women live out their lives without developing this disease.  Only a small proportion (5-10%) of women who are diagnosed with breast cancer have a family history of the disease.  This suggests that for most women, genetic factors are less important than lifestyle and environmental factors as contributors to the increasing breast cancer rate.

Disclaimer:  Information on this site is provided for informational purposes and is not meant to substitute for the advice provided by your own physician or other health professional.  Readers are urged to think carefully about the risks and benefits of different breast screening options and to seek additional information if necessary.  Inclusion of  links to other websites on this site does not imply endorsement of that organisation by BreastScreeningOptions.org nor does it imply endorsement of BreastScreeningOptions.org by any other organisation or company.