Women 50 and older who stepped down to less frequent mammograms three years after treatment for early-stage breast cancer had similar outcomes to women who received annual mammograms, according to results from the Mammo-50 trial presented at the San Antonio Breast Cancer. Symposium, held 5-9 December 2023.
Both US and UK guidelines recommend annual breast cancer screening after surgery to remove early-stage breast cancer. In the US, annual mammography is recommended indefinitely, and in the UK, it is recommended for five years, followed by screening every three years for patients aged 50 and over.
However, the optimal screening schedule has yet to be evaluated in large clinical trials, and long-term annual screening may not be necessary.”
Janet Dunn, PhD, Professor of Clinical Trials at the University of Warwick, UK
“De-escalating mammogram follow-up reduces the burden on the health care system, reduces the inconvenience for women who have to undergo these mammograms, and reduces the associated stress of waiting for results,” Dunn said. She added that stress related to screening is known to be worse for breast cancer survivors compared to women without a history of breast cancer.
In the phase III Mammo-50 trial, Dunn and colleagues enrolled 5,235 women who had undergone curative surgery to remove their cancer, had no recurrence three years after surgery, and were 50 years or older at the time of diagnosis . Participants were randomized 1:1 to receive annual mammography or less frequent mammography, defined as every two years in patients undergoing breast-conserving surgery and every three years in patients undergoing mastectomy.
After five 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 five years, 5.9% of patients in the annual mammography arm and 5.5% of patients in the de-escalation arm had relapsed. These results indicate that de-escalation did not worsen outcomes.
Adherence to the prescribed mammography schedule was lower among patients who took part in the de-escalation arm (69%, compared with 83% among patients assigned to the annual arm), but a sensitivity analysis confirmed that this had no effect on conclusions. In addition, a parallel substudy conducted annual assessments of patients’ quality of life—including measures of mental well-being, distress, and other concerns—using four validated questionnaires. no differences were detected between trial arms.
“The trial showed that outcomes from having less frequent mammograms were no worse than annual mammograms for this group of women,” Dunn said. “It is important that these kinds of trials are carried out to streamline services where possible without putting patients at a disadvantage.”
Limitations of this study include applicability only to patients over 50 years of age at diagnosis who are three or more years post-surgery.
This study was funded by the UK National Institute for Health and Care Research through the Health Technology Assessment program and funded by University Hospitals Coventry and Warwickshire NHS Trust. Dunn declares no conflict of interest.
