The Mammogram Debate: On the Ship of False Hope

From the May 2004 edition of Dr. Fuhrman's Healthy Times:

On the ship of false hope Mammograms in all age groups are a very poor screening tool. About 5 percent of mammograms are abnormal or suspicious, and of these 80 to 93 percent are false positives that cause unnecessary anxiety and further procedures, including surgery. If that were not enough to question the reliability of mammograms as a diagnostic tool, consider the unfounded reassurance that results from the false negatives that occur in 10 to 15 percent of women who already have breast cancer that will manifest clinically within one year.

In the October 2001 issue of The Lancet, the Nordic Cochrane Centre of Denmark published a follow-up report on its groundbreaking 2000 analysis of the efficacy of screening mammograms in reducing breast cancer death.1 The new report confirmed the earlier findings. After reviewing the seven largest mammography-screening trials, no benefit attributable to mammograms was found for any age group. The new research focused on the ability of mammograms to reduce total mortality because, as stated by the report’s authors, this is the only “reliable” measure of benefit.2

The Danish researchers found numerous flaws in the mammography-screening trials. They found that the studies under review did not tally fatal cases that were misclassified or that were triggered by cancer treatment such as radiotherapy. For example, none of the leukemia deaths and cardiac deaths occurring as a result of chemotherapy for breast cancer and none of the increased cases of fatal lung cancer caused by radiation to the breast during diagnosis and treatment were ever considered in prior studies. Lung cancer is a known late-stage side effect to breast cancer radiation,3 and congestive heart failure is a known late side effect of the cardiac toxicity of chemotherapy.4 The Cochrane researchers found that the studies’ claims that mammograms reduce breast cancer deaths by 25 to 30 percent were invalid, since those investigators did not consider all other deaths related to breast cancer treatments.

The researchers also found that the studies that claimed to show some benefit from mammograms for women in their fifties and sixties were 1) biased in favor of screening and 2) incorrect because they only looked at breast cancer mortality, not all-cause mortality. Based on this highly respected review, The Lancet editors concluded, “There is no reliable evidence from large randomized trials to support screening mammography at any age.”

The recent reassessment of the 2000 Cochrane analysis also confirmed that breast cancer screening with mammograms creates an overuse of aggressive treatments. The authors reasoned that the mammograms detect lots of slow-growing tumors that will never progress to cancer within the patient’s lifetime and classify these as cancer. These account for the mammograms’ so-called “successes.” There are cellular changes that may be histologically cancerous but biologically benign. Carcinoma-in-situ may be treated by bilateral mastectomy even though they do not progress to invasive disease—ever. The flawed studies count these as mammogram successes, when they are not. At the same time, the cancers that are truly invasive are not really caught early enough to make a difference. The patient only appears to live longer because the disease is diagnosed earlier. As stated previously, the same percentage of women are dying at the same ages they were before the widespread use of mammograms. The inescapable conclusion drawn from these carefully performed investigations is that mammograms do not provide a survival benefit in any age group. Those who benefit are balanced out almost equally by those who are hurt.

For more on The Mammogram Debate check out these posts:

1. Gotzsche PC, Olsen O. Is screening for breast cancer with mammography justifiable? Lancet 2000; 355:129-34.

2. Olsen O, Gotzsche PC. Cochrane review on screening for breast cancer with mammography. Lancet 2001 Oct 20;358(9290):1340-2.

3. Rubino C, de Vathaire F, Diallo I, et al. Radiation dose, chemotherapy and risk of lung cancer after breast cancer treatment. Breast Cancer Res Treat 2002 Sep;75(1):15-24.

4. Rock E, De Michele A. Nutritional approaches to late toxicities of adjuvant chemotherapy in breast cancer survivors. J Nutr 2003 Nov;133(11 Suppl 1):3785S-3793S.
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Comments (1) Read through and enter the discussion with the form at the end
Kirsten - January 3, 2007 10:42 AM

Very interesting. Thanks for digging up this extra information--it provides me with some sound reasons to avoid yet another "standard" medical procedure.

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