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Despite the long-standing claims, the evidence that routine mammography screening allows early detection and treatment of breast cancer, thereby reducing mortality, is at best highly questionable. In fact, “the overwhelming majority of breast cancers are unaffected by early detection, either because they are aggressive or slow growing" (21). There is supportive evidence that the major variable predicting survival is "biological determinism— a combination of the virulence of the individual tumor plus the host's immune response," rather than just early detection (22).
Claims for the benefit of screening mammography in reducing breast cancer mortality are based on eight international controlled trials involving about 500,000 women (23). However, recent meta-analysis of these trials revealed that only two, based on 66,000 postmenopausal women, were adequately randomized to allow statistically valid conclusions (23). Based on these two trials, the authors concluded that "there is no reliable evidence that screening decreases breast cancer mortality— not even a tendency towards an effect." Accordingly, the authors concluded that there is no longer any justification for screening mammography; further evidence for this conclusion will be detailed at the May 6, 2001, annual meeting of the National Breast Cancer Coalition in Washington, D. C., and pub-lished in the July report of the Nordic Cochrane Centre.
Even assuming that high quality screening of a population of women between the ages of 50 and 69 would reduce breast cancer mortality by up to 25 percent, yielding a reduced relative risk of 0.75, the chances of any individual woman benefiting are remote (18). For women in this age group, about 4 per-cent are likely to develop breast cancer annually, about one in four of whom, or 1 percent overall, will die from this disease. Thus, the 0.75 relative risk applies to this 1 percent, so 99.75 percent of the women screened are unlikely to benefit.
THE UNITED STATES VERSUS OTHER NATIONS
No nation other than the United States routinely screens premenopausal women by mammography. In this context, it may be noted that the January 1997 National Institutes of Health Consensus Conference recommended against premenopausal screening (24), a decision that the NCI, but not the ACS, accepted (4). However, under pressure from Congress and the ACS, the NCI reversed its decision some three months later in favor of premenopausal screening.
The U. S. overkill extends to the standard practice of taking two or more mammograms per breast annually in postmenopausal women. This contrasts with the more restrained European practice of a single view every two to three years (4).
COSTS OF SCREENING
The dangers and unreliability of mammography screening are compounded by its growing and inflationary costs; Medicare and insurance average costs are $70 and $125, respectively. Inadequate Medicare reimbursement rates are now prompting fewer hospitals and clinics to offer mammograms, and deterring young doctors from becoming radiologists. Accordingly, Senators Charles Schumer (D-NY) and Tom Harkin (D-IA) are introducing legislation to raise Medicare reimbursement to $100 (42).
If all U. S. premenopausal women, about 20 million according to the Census Bureau, submitted to annual mammograms, minimal annual costs would be $2.5 billion (4). These costs would be increased to $10 billion, about 5 percent of the $200 billion 2001 Medicare budget, if all postmenopausal women were also screened annually, or about 14 percent of the estimated Medicare spending on prescription drugs. Such costs will further increase some fourfold if the industry, enthusiastically supported by radiologists, succeeds in its efforts to replace film machines, costing about $100,000, with the latest high-tech digital machines, approved by the FDA in November 2000, costing about $400,000. Screening mammography thus poses major threats to the financially strained Medicare system. Inflationary costs apart, there is no evidence of the greater effectiveness of digital than film mammography (43), as confirmed by a study reported at the November 2000 annual meeting of the Radiological Society of North America (44). In fact, digital mammography is likely to result in the increased diagnosis of ductal carcinoma-in-sutu (DCIS).
The comparative cost of CBE and mammography in the 1992 Canadian Breast Cancer Screening Study was reported to be 1 to 3 (45). However, this ratio ignores the high costs of capital items including buildings, equipment, and mobile vans, let alone the much greater hidden costs of unnecessary biopsies, specialized staff training, and programs for quality control and professional accreditation (46). This ratio could be even more favorable for CBE and BSE instruction if both were conducted by trained nurses. The excessive costs of mammography screening should be diverted away from industry to breast cancer prevention and other
women's health programs.
“Mammography’s Mixed Blessings”
Canadian Research Study finds Failure of Mammography
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9. Martinez, B. Mammography centers shut down as reimbursement feud rages on. Wall Street Journal, October 30, 2000, p. A-1.
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19. Miller, A. B., et al. Canadian National Breast Screening Study-2: 13-year results of a randomized trial in women aged 50– 59 years. J. Natl. Cancer Inst. 92(18): 1490– 1499, 2000.
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21. Napoli, M. What do women want to know. J. Natl. Cancer Inst. Monogr. 22: 11– 13, 1997.
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23. Gotzsche, P. C., and Olsen, O. Is screening for breast cancer with mammography justifiable? Lancet 355: 129– 134, 2000.
24. National Institutes of Health Consensus Development Conference Statement. Breast cancer screening for women ages 40– 49, January 21– 23, 1997. J. Natl. Cancer Inst. Monogr. 22: 7– 18, 1997.
Excerpted from “Dangers and Unreliability of Mammography: Breast Examination is a Safe, Effective and Practical Alternative”, by Samuel S. Epstein, Rosalie Bertell, and Barbara Seaman, International Journal of Health Services, Volume 31, Number 3, 2001
Samuel S. Epstein, M.D.
Chairman, Cancer Prevention Coalition
c/o University of Illinois at Chicago
School of Public Health, M/C 922
2121 W. Taylor Street
Chicago, IL 60612