Two studies suggest that annual mammography screening beginning at age 40 is not only safe but highly effective in reducing breast cancer deaths. Stephen A. Feig, M.D., professor of radiology at Jefferson Medical College of Thomas Jefferson University, Philadelphia, and director of the Breast Imaging Center, Thomas Jefferson University Hospital, has found that the benefits of annual mammography far outweigh the risk of developing breast cancer from accompanying radiation exposure. Feig presented his findings this week at the 83rd Scientific Assembly and Annual Meeting of the Radiological Society of North America in Chicago.
The study compared the increases in life expectancies that women gained through screenings against those potentially lost to radiation-induced cancers. Dr. Feig analyzed a variety of studies on radiation risks and mammography benefits.
Dr. Feig notes that screening risks are negligible or nonexistent compared with the benefits. "No woman has ever been shown to have developed breast cancer from mammography," he notes. The possibility of reducing risk from mammography has been raised because of increased breast cancer incidence observed among Japanese victims of the Hiroshima and Nagasaki bombs, and by women who were treated with radiation therapy for benign breast conditions or who were given chest fluoroscopies during tuberculosis treatment in the 1920s. Such women received up to 2,500 times more radiation than a woman gets during a mammogram. Yet, he says, "there’s still this unfounded concern about getting cancer from mammography radiation."
Dr. Feig estimated that based on results from multiple screening trials conducted around the world, annual mammography screening would reduce death due to breast cancer by at least 35 percent in women aged 40 to 49 compared to at least 24 percent when mammograms are given every other year. The death rate is lowered by 45 percent in women ages 50 to 59 when mammograms are given annually compared to 39 percent when done every other year.
The more often a woman is screened, the more likely breast cancer will be caught early and treated more effectively. "The real risk is not in getting mammography," says Dr. Feig, "but in not getting mammography. The risk is conjecture; the benefit is real."
Dr. Feig reiterated this point in an editorial he wrote in the December issue of the journal Cancer , in which Swedish scientists reported the results of a study performed in Gothenburg, Sweden. The study showed that performing mammography screening in women between ages 39 to 49 every year and a half would result in a 45 percent reduction in cancer deaths. Dr. Feig calculated that if all women in the trial actually had been screened annually instead, there might have been as much as a 75 percent reduction in breast cancer deaths.
"Considering the reasonable cost and the fact that the benefits outweigh the risks, there is no reason I can think of as to why women shouldn’t get this lifesaving screening," Dr. Feig concludes.
Earlier this year, the American Cancer Society and the National Cancer Institute both recommended that women 40 and older have regular mammograms.