The authors point out that the risk of developing and dying from breast cancer increases as women get older and that "older women [age 65 and up] account for 48% of newly diagnosed breast cancers and 58% of breast cancer deaths." Also, they observe that the mortality from breast cancer is increasing in older women, "possibly because they are less likely to undergo regular mammography."

Although it is true that early detection with mammography decreases a woman?s chances of dying from breast cancer, the authors note that it is unknown whether this applies to older women. Only one of the original trials that demonstrated the benefits of mammography screening studied women as old as 74. But that trial had only a small number of older women so results were inconclusive.

McCarthy and her colleagues tried to answer the question of whether screening mammography benefits older women by looking at women age 67 and older in a special national cancer database called the Linked Medicare-Tumor Registry Database. This database combines information from Medicare, which identifies those who received mammograms, with information from national cancer registries, which reveals who had breast cancer. The registry information also discloses at what stage the breast cancer was discovered and if it was fatal.

McCarthy and her team then compared women who had regular mammograms with women who did not. Both groups had been diagnosed with breast cancer. They found 2,029 "nonusers," meaning the women had not had a mammogram for two years before they were diagnosed with breast cancer, and 2383 "regular users," referring to women with at least two mammograms 10 or more months apart in the two years before their diagnosis of breast cancer.

The researchers wanted to know if the nonusers were more likely to have their cancer discovered at a later stage and whether nonusers were more likely to die of breast cancer.

In both instances, nonusers fared worse than regular users. The women who did not have regular mammograms before their diagnosis were three times more likely to be diagnosed with late-stage breast cancer. These women were also two to three times more likely to die from their breast cancer. The women?s ages did not seem to matter. The higher stage at diagnosis and higher death rate held true for nonusers at any stage. These findings led the authors to conclude that "the data support the use of regular mammography in older women and suggest that mammography can reduce breast cancer mortality for older women, even for women age 85 and older."

Robert Smith, PhD, director of cancer screening for the American Cancer Society, says there is little reason to believe that screening would not be helpful in finding small tumors in older women. "The ACS position has always been that as long as a woman is in good health, she should get mammograms. Good health might be defined in terms of whether or not she is a candidate for treatment if a cancer is detected."