Mammography Overused in Older Breast Cancer Survivors, Study Suggests

By Monica J. Smith

BOSTON—Use of surveillance mammography is high in older women with a history of breast cancer, even when their life expectancy and risk for recurrence or a new primary cancer are low, according to new research.

“Current National Comprehensive Cancer Network guidelines recommend annual mammography for women after breast-conserving surgery. There are risks and benefits, however, associated with surveillance that vary depending on the patient’s histologic subtype of breast cancer, the patient’s life expectancy [LE] and the patient’s preference,” said Elizabeth Berger, MD, MS, an assistant professor of surgery at Yale School of Medicine, in New Haven, Conn.

To address uncertainties around the use of surveillance mammography in women treated at an older age for breast cancer, Dr. Berger and her colleagues used SEER (Surveillance, Epidemiology, and End Results) data to identify women aged 67 years and older with a diagnosis of a primary breast cancer between 2003 and 2007, following them from one year post-diagnosis until the occurrence of either a second primary breast cancer, death or the end of follow-up in 2017.

“Our primary outcome of interest was receipt of surveillance mammography, and we used a validated method to estimate life expectancy using age and comorbidities from administrative claims data,” Dr. Berger said.

Their final cohort consisted of 43,962 patients with a mean age of 76 years at diagnosis. Divided by LE, 26% were expected to live less than five years, 36% had an LE of six to 10 years, and 38% were expected to live another 10 or more years.

The majority, about 32,000 patients, had stage I/II breast cancer and 72% were hormone receptor–positive. More than half (55%) had at least one comorbidity, and 16% had three or more. Due to the cohort time, information about HER2 status was not available.

The incidence of surveillance mammography was high. Even those with the shortest LE had five mammograms per 10 person-years of follow-up. Those with a greater than 10-year LE had approximately six mammograms per 10 person-years of follow-up.

“This means that 21% of women with less than five years’ LE received a surveillance mammography after treatment, and 48% of women received one with 10 or more years of LE,” Dr. Berger said. Of note, 51% of those with an LE of less than one year had a mammogram within the last 12 months of life.

They then quantified the incidence of a second primary breast cancer by LE. “The cumulative incidence is low: 3.7% in those with an LE less than five years, 4.9% in those with a six- to 10-year LE and 7.6% in those with greater than 10 years’ LE, and this was at the 10-year follow-up,” Dr. Berger said.

This pattern varied by histologic subtype, with risk being lower, as one would expect, in women with hormone receptor–positive cancers than in those with hormone receptor–negative cancers. But even in the latter cohort, the risk for a second primary cancer was still relatively low: 3% in the five-year LE group, 6% in the six- to 10-year LE group and 8.5% in those expected to live 10 or more years.

Dr. Berger acknowledged that some may wonder why surveillance mammography for any of these women is an issue. “But there are such things as overdiagnosis and the potential harms of false positives. We also must consider competing mortality risks among older women after breast cancer when considering surveillance mammography,” she said.

Dr. Berger presented the research at the 2023 meeting of the American Society of Breast Surgeons.

Melissa Pilewskie, MD, an associate professor of surgery and the director of the Breast Care Center at the University of Michigan, in Ann Arbor, noted that Dr. Berger’s findings are consistent with several other studies reporting a high interest in continuous cancer surveillance among older patients, “potentially regardless of life expectancy and health status,” she said.

Dr. Pilewskie acknowledged that it can be time-consuming to address de-escalation and discontinuation of screening in practice. “But we as providers need to reevaluate the routine use of breast screening among elderly patients rather than continue reflex ordering, as mammography is not without potential harms, including the obvious risks of false positives and medical cost, but also the potential added stressors of travel, time away from home, testing anxiety, overdiagnosis and discomfort.

“While these conversations can be challenging in the clinical setting, these data highlight the need to identify improved communication strategies to enhance a shared decision-making process that supports individual beliefs in the context of cancer risk and potential testing harms.”