Breast cancer screening in the US is common among women 80 years of age or older, but it is of little benefit to the majority of them, according to a new study.

A recent review concluded that breast cancer screening is not worthwhile when life expectancy is less than 10 years, the researchers note, and most women 80 or older have a life expectancy of less than 10 years.

In a population-based study, Dr. Mara A. Schonberg and colleagues from Beth Israel Deaconess Medical Center, Boston, examined national rates of breast cancer screening in women at least 80 years of age.

The study looked at information provided by a representative sample of 882 such women who responded to the 2000 National Health Interview Survey.

More than half of the women (51 percent) had undergone a screening mammogram within the previous 2 years, the investigators report in the Journal of the American Geriatrics Society.

Forty-two percent of the women were 85 years of age or older, 20 percent had at least two significant diseases, and 12 percent were dependent in at least one activity of daily living.

Overall, 44 percent of women with at least two significant diseases had undergone screening, statistically similar to the 54 percent of women without significant disease.

Screening rates were 37 percent among women with at least one functional dependency, compared with 56 percent of those without impairment.

“More than half of women for whom mammography was considered unlikely to be beneficial and 39.4 percent of women for whom mammography was considered very unlikely to be beneficial were screened, representing 774,000 and 512,000 women aged 80 and older nation-wide, respectively,” Schonberg’s group estimates.

“Further research is needed to explore patient preferences and beliefs about screening in this age group to make sure women are choosing to be screened in accordance with their values and preferences based on accurate information,” the team adds.

SOURCE: Journal of the American Geriatrics Society, October 2004.