Women aged 50 or older who had less-frequent mammography 3 years after curative surgery for early-stage breast cancer had similar outcomes as women who had annual mammography, according to results from the Mammo-50 trial presented at the 2023 San Antonio Breast Cancer Symposium (Abstract GS03-02).
Both U.S. and UK guidelines recommend annual breast cancer screening after surgery to remove early-stage breast cancer; in the United States, annual mammography is recommended indefinitely, and in the United Kingdom, it is recommended for 5 years, followed by screening every 3 years for patients aged 50 and older.
However, the optimal screening schedule has yet to be evaluated in large clinical trials, and long-term annual screening may not be necessary, explained Janet Dunn, PhD, Professor of Clinical Trials at the University of Warwick. “De-escalation of mammographic surveillance reduces the burden on the health-care system, decreases the inconvenience for women having to undergo these mammograms, and reduces the associated stress of waiting for results,” Dr. Dunn said. She added that screening-related anxiety is known to be worse for breast cancer survivors than for women without a history of breast cancer.
Mammo-50 Details and Results
In the phase III Mammo-50 trial, Dr. Dunn and colleagues enrolled 5,235 women who had undergone curative surgery to remove their cancer, were free of recurrence 3 years after surgery, and were 50 years or older at the time of their diagnosis. Participants were randomly assigned 1:1 to receive annual mammography or less-frequent mammography, defined as every 2 years in patients who underwent breast-conservation surgery and every 3 years in patients who had a mastectomy.
After 5 years of follow-up, breast cancer–specific survival was 98.1%, and overall survival was 94.7% among patients in the annual mammography arm. For patients receiving less-frequent mammography, breast cancer–specific survival was 98.3%, and overall survival was 94.5%. Similarly, at 5 years, 5.9% of patients in the annual mammography arm and 5.5% of patients in the de-escalation arm had experienced a cancer recurrence.
Compliance with the assigned mammography schedule was lower among patients assigned to the de-escalation arm (69% vs 83% among patients assigned to the annual mammography arm). However, a sensitivity analysis confirmed this had no effect on the conclusions. Additionally, a concurrent substudy included annual evaluations of patients’ quality of life—including measures of mental well-being, distress, and other concerns—using four validated questionnaires; no differences were detected between the trial arms.
“The trial demonstrated that the outcomes from undergoing less-frequent mammograms were no worse than undergoing annual mammograms for this group of women,” Dr. Dunn said. “It is important to carry out these types of trials to streamline services where possible, while not disadvantaging patients.”
Limitations of this study include the applicability exclusively to patients older than age 50 at diagnosis who are 3 or more years postsurgery.
Disclosure: This study was funded by the UK National Institute for Health and Care Research through the Health Technology Assessment program and sponsored by University Hospitals Coventry and Warwickshire NHS Trust.
