IS MAMMOGRAPHY INEFFECTIVE AND POTENTIALLY HARMFUL?
Presently, we rely on procedures such as the mammogram for early detection of breast cancer. Although widely used, the technique is fraught with difficulties ranging from mere inaccuracy to possibly causing bodily harm. The October 2001 issue of the British Medical Journal, The Lancet, analyzed the seven major studies that have been the foundation upon which the cancer establishment rests its proclamation that mammograms saves lives. This Danish study concluded that the case for screening mammography remains unproven at best. “At present there is no reliable evidence from large randomized trials to support screening mammography programs” (1). The test is largely ineffective as a screening tool for detecting cancer in sufficient time to influence survival rates.
Because mammography is such a large revenue earner, any studies challenging its safety or effectiveness are themselves challenged. Is one witnessing honest disagreement within the medical community regarding deceptive analyses of the data, or unscrupulous sales tactics masquerading as scientific inquiry?
University of Toronto’s Dr. Cornelia Baines, Deputy Director of the Canadian National Breast Screening Study, has pointed to an almost willful silence concerning both the dangers and ineffectiveness of screening mammography. Regarding the dangers, she states that: “For up to 11 years after the initiation of breast cancer screening in women aged 40-49 years, screened women faced a higher death rate from breast cancer than unscreened control women, although that is contrary to what one would expect … three years after screening starts, their chance of death from breast cancer is more than double”. (2)
Although these findings are counterintuitive, Baines further points out that in clinical trials conducted on two continents spanning 30 years, excess deaths in screened women 40-49 have been observed for up to 10 years after mammography is begun. Even those who disagree with Baines’ disturbing conclusions regarding the increased mortality rates in this age group generally agree the benefits of mammography are smaller in women younger than 50 years of age compared to those over 50. Many researchers now admit that any reduction in mortality in the 40-49 age group that may result from screening mammography is modest at best, and when these modest benefits have been reported in the research literature, they have been statistically insignificant when compared to those not receiving mammography.
If the increase in the incidence of breast cancer in mammogram-screened pre-menopausal women ages 40-49 continues to be demonstrated in future studies, as Dr. Baines maintains it will be, it may ultimately be explained by a combination of factors, including:
• Early detection of a tumor leads to surgical intervention. Removal of a primary tumor can induce the growth and proliferation of dormant micro-metastases which already exist at distant sites;
• In response to surgery, the body produces growth factors to accelerate healing. This in turn accelerates tumor growth;
• The trauma of surgery is known to suppress the immune system;
• The exposure of breast tissue to ionizing radiation produces damaging free radicals.
Mammography is one of the pillars of America’s War on Cancer. Many doctors, government related institutions, and industry lobbying groups recommend an annual screening mammogram for all women beginning at 40 years of age. Yet, the scientific literature shows screening mammography provides little if any survival benefits in pre-menopausal women, and it may increase the risk of dying compared to women who do not receive mammograms. In April 2008, an influential physician’s group publically declared their opposition to the general practice of giving annual screening mammograms to women 40-49, stating that women within this age group are not at a uniform risk of cancer and that mammograms themselves could expose them to harm from needles treatment because of false positive evaluations. In women 50 and older, the benefit of increased survival becomes more pronounced.
Diagnostic mammograms, as opposed to screening mammograms, are administered when cancer is suspected and when any possible tumors would be presumed to be larger and more easy to detect. From 1996 through 2003, a three State study (3) led by Group Health Cooperative of Seattle, Washington, demonstrated that even the most skilled radiologists fail to detect 20% of breast cancer cases evaluated by diagnostic mammograms. The researchers examined 35,895 mammograms which had been evaluated by 123 radiologists. Accuracy of the evaluation varied greatly, with the worst radiologists missing nearly 40% of existing tumors and misidentifying 8.3% of the patients as having non-existent tumors (false positives). The top evaluators tended to be physicians at academic medical centers and/or practitioners specializing in breast imaging with at least 20% of their time dedicated to breast evaluation. Even these radiologists failed to detect 20% of the existing tumors while having a 2.6% false positive rate.
One additional fact women should know is that in 2000, researchers published the results of a review of the medical records of 2,227 women between the ages 40-69. They concluded that after an average of nine mammograms, the risk of a false positive test was more than 43%. (4). A false positive mammogram may lead to unnecessary procedures such as lymph node removal or mastectomy, just to be safe.
1. Olsen.O and Gotzsche P. “Cochrane review on screening breast cancer and mammography”. Lancet, Vol. 358 October 20, 2001, pp 1340-42. Horton R. “Screening mammography – an overview revisited”. Lancet Vol. 358, pp 1284-85 October 20, 2001
2. Baines C. “Mammography screening: Are women really giving informed concent?” Journal of the National Cancer Institute, 95(20); 1508-1511 October 15, 2003.
3. Miglioretti D.L. et al. ‘Radiologists characteristics with interpretive performance of diagnostic mammography” Journal of the National Cancer Institute, 99:1854-63, 2007.
4. “Predicting the cumulative risk of false-positive mammograms”. Journal of the National Cancer Institute, 92(20) 1657-66, 2000.