Less frequent mammograms non-inferior to annual mammograms in breast cancer patients over 50 years: Study

A new study published in the journal of The Lancet showed that occasionally performed mammograms were not inferior to yearly mammograms for breast cancer-specific survival, recurrence-free interval, and overall survival for patients 50 years of age or older.

Globally, there are differences in the frequency of mammography monitoring for women following a breast cancer diagnosis. This study sought to determine if less frequent mammograms were not associated with a lower breast cancer-specific survival rate in women who were 50 years of age or older at diagnosis, 3 years after treatment for operable breast cancer, and disease-free.

Mammo-50 was a multicenter, randomized, phase 3 trial for women 50 years or older with an initial diagnosis of invasive or non-invasive breast cancer who were free of recurrences 3 years after curative surgery. It compared annual mammograms to less frequent mammograms. The trial took place at 114 National Health Service institutions across the United Kingdom.

3 years after curative surgery, patients were randomly assigned (1:1) to yearly or less frequent mammograms and were followed for 6 years. Co-primary outcomes were cost-effectiveness and breast cancer-specific survival. The cost-effectiveness study will be published elsewhere. The intention-to-treat population's survival was evaluated specifically for breast cancer.

Overall survival, recurrence-free interval, and hospital system referrals were secondary outcomes. With 2·5% one-sided significance, 5000 women had 90% power to identify a 3% absolute non-inferiority margin for breast cancer-specific survival. 

A total of 5,235 women were randomized to either less frequent (n=2617) or yearly (n=2618) mammograms between April 22, 2014, and September 28, 2018. Nearly, 4,202 (80·3%) women had conservation surgery, 4,576 (87·4%) had invasive disease, 1,159 (22·1%) had node-positive disease, 4,330 (82·7%) had oestrogen receptor-positive tumors, and 3,858 (73·6%) were 60 years of age or older.

Close to 343 women passed away over a median follow-up of 5·7 years, 116 of whom had breast cancer. At the predetermined 3% margin, the 5-year breast cancer-specific survival was 98·1% for the annual mammography group and 98·3% (97·8–98·8) for the less frequent mammography group, indicating that less frequent mammography is not inferior.

In the yearly mammography group, the 5-year recurrence-free interval was 94·1%, while in the less frequent mammography group, it was 94·5%. Overall, this study found that women who have received yearly mammographic monitoring for 3 years and show no symptoms of recurrence can safely have fewer frequent mammograms. 

Reference:

Dunn, J. A., Donnelly, P., Elbeltagi, N., Marshall, A., Hopkins, A., Thompson, A. M., Audisio, R., Pinder, S. E., Cameron, D. A., Hartup, S., Turner, L., Young, A., Higgins, H., Watson, E. K., Gasson, S., Barrett-Lee, P. J., Hulme, C., Shinkins, B., Hall, P. S., & Evans, A. (2025). Annual versus less frequent mammographic surveillance in people with breast cancer aged 50 years and older in the UK (Mammo-50): a multicentre, randomised, phase 3, non-inferiority trial. Lancet, 405(10476), 396–407. https://doi.org/10.1016/S0140-6736(24)02715-6