Amid ongoing controversy about the ability of mammography exams to lower women's risk of death from breast cancer, US health officials February 21 released new clinical guidelines recommending even more widespread use of mammograms to detect the disease.
The new guidelines, issued by the US Preventive Services Task Force, call on all women over 40 to receive screening mammograms every 1 to 2 years, though the specific interval is left up to women and their doctors.
Previous recommendations issued by the task force in 1989 and 1996 reserved screening for women over 50 years of age.
Officials said they did not have strong enough scientific evidence to recommend the age at which women should receive their first mammogram, or at exactly what interval they should go for repeat screenings.
Officials gave widespread mammography strong backing even as scientists continue to grapple with the ramifications of a Danish study released in October 2001 that questioned the value of mammogram screening in reducing breast cancer mortality.
The authors of that study, published in the British medical journal The Lancet, concluded that previous research showing a benefit was flawed and that widespread mammogram screening is unjustified.
Specifically, the Danish researchers argued that earlier studies in Europe and North America were improperly randomized and that they used a faulty definition of breast cancer survival.
Reviewers had been working on the guidelines since first convening in 1998 and that last October's Danish review did not cause them to speed up their release. Still, the National Cancer Institute offered its endorsement to the new recommendations before its scientific review committee issued a report on the overall quality of mammography data.
Officials stressed that mammography screening is not foolproof.
The technology carries a first-time false positive rate of up to 6%. False positives can lead to expensive repeat screenings and can sometimes result in unnecessary invasive procedures including biopsies and surgeries.
Reuters Washington
Should You Get a Mammogram?Danish researchers say a re-analysis of their controversial study of a year ago confirms their original conclusions -- that there is no evidence that breast-cancer screening with mammography saves women's lives.
When the original report was published last year in The Lancet, it garnered widespread criticism from breast cancer experts who questioned the researchers' reasoning and conclusions. So researchers re-analyzed their data according to the protocol of an international organization that has established rigorous standards for conducting and publishing research reviews.
But their conclusion about mammography remains the same.
According to the researchers flawed methods have troubled studies that have indicated mammography saves women's lives by catching breast cancer early. Out of eight studies they reviewed, they deem only two to be of good quality.
Further documentation of the questionable benefits of mammography and the possible potential for the less invasive procedure of breast examination to reduce breast cancer risks.And those two trials suggested that mammograms have made no dent in breast cancer deaths.
In their original study, the researchers cited problems with the way many mammography trials have been convey charge skewed the study results in favor of mammography.
Based on the current report, Lancet editor, Richard Horton, concludes ducted -- including imbalances in terms of the women's ages and other factors that "at present, there is no reliable evidence from large randomized trials to support screening mammography programs."
The Lancet
More on the Dangers of Mammography
Recent confirmation by researchers of longstanding evidence on the ineffectiveness of screening mammography has been greeted by extensive nationwide headlines. Entirely missing from this coverage, however, has been any reference to the well-documented dangers of mammography.
Screening mammography poses significant and cumulative risks of breast cancer for premenopausal women. The routine practice of taking four films of each breast annually results in approximately 1 rad (radiation absorbed dose) exposure, about 1,000 times greater than that from a chest x-ray.
The premenopausal breast is highly sensitive to radiation, each 1 rad exposure increasing breast cancer risk by about 1 percent, with a cumulative 10 percent increased risk for each breast over a decade's screening. These risks are even greater for younger women subject to "baseline screening."
Radiation risks are some four-fold greater for the 1 to 2 percent of women who are silent carriers of the A-T (ataxia-telangiectasia) gene; by some estimates this accounts for up to 20 percent of all breast cancers diagnosed annually.
Since 1928, physicians have been warned to handle "cancerous breasts with care -- for fear of accidentally disseminating cells" and spreading the cancer. Nevertheless, mammography entails tight and often painful breast compression, particularly in premenopausal women, which could lead to distant and lethal spread of malignant cells by rupturing small blood vessels in or around small undetected breast cancers.
Missed cancers are common in premenopausal women owing to their dense breasts, and also in postmenopausal women on estrogen replacement therapy.
Mistakenly diagnosed cancers are common. For women with multiple risk factors including a strong family history and early menarche -- just those strongly urged to have annual mammograms -- the cumulative risks of false positives can reach as high as 100 percent over a decade's screening.
The widespread acceptance of screening has lead to overdiagnosis of pre-invasive cancer (ductal carcinoma in situ), sometimes treated radically by mastectomy and radiation, and even chemotherapy.
As increasing numbers of premenopausal women are responding to aggressively promoted screening, imaging centers are becoming flooded. Resultingly, patients referred for diagnostic mammography are now experiencing potentially dangerous delays, up to several months, before they can be examined.
The dangers and unreliability of screening are compounded by its growing and inflationary costs. Screening all premenopausal women would cost $2.5 billion annually, about 14 percent of estimated Medicare spending on prescription drugs.
These costs would be increased some fourfold if the highly profitable industry, enthusiastically supported by radiologists, succeeds in replacing film machines, costing about $100,000 each, with the latest high-tech digital machines recently approved by the FDA, costing about $400,000 each, for which there is no evidence of improved effectiveness.
The ineffectiveness and dangers of mammography pose an agonizing dilemma for the millions of women anxious for reassurance of early detection of breast cancer. However, the dilemma is more apparent than real.
As proven by a September 2000 publication, based on a unique large-scale screening study by University of Toronto epidemiologists, monthly breast self-examination (BSE) following brief training, coupled with annual clinical breast examination (CBE) by a trained health care professional, is at least as effective as mammography in detecting early tumors, and also safe.
National networks of BSE and CBE clinics staffed by trained nurses should be established to replace screening mammography. Apart from their minimal costs, such clinics would empower women and free them from increasing dependence on industrialized medicine and its complicit medical institutions.
Samuel S. Epstein, M.D.
Professor Emeritus Environmental and Occupational Medicine Chairman, Cancer Prevention Coalition
University of Illinois at Chicago School of Public Health
312-996-2297
Web site: http://www.preventcancer.com
For further details and supporting documentation, see "Dangers and Unreliability of Mammography: Breast Examination is a Safe, Effective and Practical Alternative," by Samuel S. Epstein, Barbara Seaman and Rosalie Bertell, International Journal of Health Services, volume 31(3):605-615, 2001.
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