Women 80 and older benefit from mammography, but few are screened

April 22, 2008

In the first study to assess mammography in women 80 and older, researchers found that having regular mammograms significantly decreases the risk of being diagnosed with late-stage breast cancer, but only about one-fifth of women in this age group receive them regularly.

The study, which is being published online April 21 in the Journal of Clinical Oncology (JCO), also showed that each mammogram that was performed in these older women was associated with a further reduction in the risk of being diagnosed with late-stage disease. It is estimated that approximately 17 percent of breast cancer cases in the U.S. are found in women 80 and older.

“This study suggests that mammography benefits may have no age limit and that women should consider being screened on a regular basis, even into their 80s and possibly 90s, depending on their current health status,” explained Brian D. Badgwell, MD, a surgical oncology fellow at The University of Texas M. D. Anderson Cancer Center and the study’s lead author.

“Mammography has been shown to be an excellent means of detecting breast cancer early, when it is most likely to be cured. We found that when breast cancer was diagnosed, it was more likely to be found at an early stage when a woman had at least three mammograms in the five-year period before diagnosis.” He recommended that healthcare providers and their older female patients—particularly women in reasonably good health—discuss the benefits of mammography.

The American Cancer Society recommends annual mammography beginning at age 40, with no upper age limit for women in good health. However, many older women aren’t following those guidelines. Real-world experience has shown that women are less likely to get regular mammograms as they age, especially if they have medical conditions that are likely to limit their life expectancy.

Using Surveillance, Epidemiology, and End Results (SEER) Medicare data for the years 1996 to 2002, Dr. Badgwell and colleagues examined mammography use in the five-year period before breast cancer diagnosis among 12,358 women age 80 and older. Those who had no mammograms during that period were considered nonusers; irregular users had one to two mammograms and regular users had three or more mammograms.

They found that only 22 percent of women were regular users of mammography, 29 percent were irregular users and 49 percent had no mammograms in the five years before their diagnosis. Regular users were more likely to be diagnosed with stage I disease, while stage II-IV breast cancers were more commonly found among the nonusers and irregular users. For example, 68 percent of regular users were found to have stage I disease, compared with 56 percent of irregular users and 33 percent of nonusers. Similarly, only 32 percent of regular users had stage II-IV cancers, compared with 44 percent of irregular users and 67 percent of nonusers.

Five-year survival from breast cancer was greatest among regular users (94 percent) and lower among irregular users (88 percent) and nonusers (82 percent). However, the researchers cautioned against linking mammography use to better survival, because survival from diseases other than breast cancer was also better among women who had regular mammography (80 percent) compared with irregular users (69 percent) and nonusers (59 percent)—suggesting that regular users may be in a better state of health compared with women who don’t undergo regular mammography.

Source: American Society of Clinical Oncology