General Risks of Breast Screening

8 Jan

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.