The mammography debateJune 3, 2002
Most of us, either directly or indirectly, have been affected by breast cancer. It is the most common cancer, other than skin cancer, and the second-leading cause of cancer deaths in
women. The American Cancer Society predicts that 203,500 new cases will be diagnosed and that 40,000 women will die of the disease in 2002.
Mammography, a low-dose X-ray of the breast, has been used as
a screening tool to detect breast cancer by millions of women during the last two decades. The rationale for this screening was based on seven major studies conducted since 1960 that seemed to indicate that mammography -- and the resultant early detection and treatment of malignancies -- reduced the death rate from breast cancer.
But do mammograms save lives? That question has been hotly debated within the medical and scientific communities since October 2001, when Danish researchers questioned the validity of the original seven studies. Their findings, published in the British medical journal Lancet and endorsed by its editor, concluded that five of these studies had design flaws that rendered the results suspect, and the remaining two did not demonstrate that mammography saved lives.
The controversy generated by the Lancet article had experts lining up on both sides of the mammography debate, with some saying that it saves lives by detecting cancer early, and others concluding that the statistical evidence is lacking. In the wake of the controversy, women were left bewildered and in need of guidance.
In February, the U.S. Preventative Services Task Force, a 15-member committee of independent experts that advises the federal government on preventative health matters, announced the results of its review of mammography studies published since 1996. The task force concluded that mammography significantly reduces breast cancer deaths. As a result of these findings, the U.S. Department of Health and Human Services (HHS) issued new guidelines that urge screening mammograms every one to two years for women age 40 and over.
Mammography is not a perfect screening tool. According to the task force's report, most abnormalities -- 80 percent to 90 percent -- detected by screening mammograms are not cancer. These false-positives often create anxiety in women who may need additional screening, and in some cases surgical biopsy, to evaluate the suspicious finding. Mammograms also fail to detect existing cancers 5 percent to 20 percent of the time.
Despite these flaws, mammography remains a valuable tool for the early detection of breast cancer, according to Tommy G. Thompson, HHS secretary, who announced the federal screening recommendations in February. The death rate from breast cancer has declined in the last decade, and Thompson and other
experts credit early detection through mammography for part of that decline.
As with any medical question, consult your personal physician. For more information about breast cancer, visit the American Cancer Society's Web site.
Beal is a lecturer in Baylor's Louise Herrington School of Nursing, where she teaches "The Experience of Illness." She received her BS from Columbia University and her MN from Emory. She is a freelance health and medical writer.