Annual breast cancer screening in women older than 75 years may not reduce mortality

Women may not need annual breast cancer screening past the age of 75 years, according to research published in the Annals of Internal Medicine that found continuing screening after that age did not lead to substantial reductions in breast cancer mortality.

Xabier García-Albéniz, MD, PhD, visiting scientist in the department of epidemiology at Harvard T.H. Chan School of Public Health, told Healio Primary Care that it is important to determine when to safely stop annual screening.

“Because every medical intervention entails risks, cancer screening can have false positives and can cause stress in women who may not be gaining any benefit from it,” he said.

García-Albéniz, also from Massachusetts General Hospital and RTI Health Solutions, and colleagues wrote that current guidelines for screening in women aged 75 years and older vary and the U.S. Preventive Services Task Force stated that evidence is insufficient to evaluate the benefits and harms of screening in these women.

The researchers estimated the impact of continuing or stopping annual mammogram screening at the age of 75 years in a population-based, observational study. Using Medicare data from 1999 through 2008, they emulated a target trial in which women aged 70 to 74 years or 75 to 84 years who had recently undergone a screening mammography were randomly assigned to either stop screening or continue mammography every 12 months. Participants included in the analyses were considered to have a high chance of survival for an additional 10 years.

During follow-up, researchers identified 1,533 breast cancer deaths among those who continued screening and 1,304 deaths in those who stopped screening.

Among women aged 70 to 74 years, researchers found the estimated 8-year risk for breast cancer mortality was 2.7 (95% CI, 1.8-3.7) deaths per 1,000 women in the group with continued screening and 3.7 (95% CI, 2.7 to 5) deaths per 1,000 women in the group that stopped screening (hazard ratio = 0.78; 95% CI, 0.63 to 0.95). This finding suggests that women in this age group should continue to undergo screening, the researchers noted.

For women aged 75 to 84 years, the estimated 8-year risk for breast cancer mortality was 3.8 (95% CI, 2.7-5.1) deaths per 1,000 women with the continued screening strategy and 3.7 (95% CI, 3-4.6) deaths per 1,000 women with the stop screening strategy (HR = 1; 95% CI, 0.83-1.19), suggesting that continued screening in these women does not appear to affect their risk for breast cancer mortality, according to the researchers.

In both age groups, researchers found that women diagnosed with breast cancer within the stop screening group were more likely to undergo chemotherapy than those in the continued screening group but were less likely to have other aggressive treatments, such as radiotherapy and lumpectomies.

“The findings provide new information for elderly women and their doctors considering to stop receiving breast cancer screening,” García-Albéniz said.

In an editorial accompanying the study, Otis W. Brawley, MD, a Bloomberg Distinguished Professor at Johns Hopkins University, noted the findings may not represent current practice as digital mammography — now used for most screenings — was newly introduced during the study period.

He also noted that a study is underway to determine if using 3Dmammography — which reportedly has an improved cancer detection ability and a lower-false positive rate than traditional mammography — leads to improved outcomes.

While modeling studies help estimate the risk for the average woman, “the physician making a clinical decision must do so for an individual patient,” Brawley wrote.

“In the future, breast cancer screening recommendations are more likely to be tailored to the individual or personalized using objective risk-simulation models,” he wrote. – by Erin Michael

Disclosures: Brawley reports receiving personal fees from Genentech outside the submitted work. García-Albéniz reports no relevant financial disclosures. Please see study for all other authors’ relevant financial disclosures.