Multicenter noninferiority phase 3 trial of annual versus less frequent mammography surveillance in breast cancer patients aged 50 year or older

The frequency of mammographic surveillance for women after diagnosis of breast cancer varies globally. The noninferiority phase 3 Mammo-50 trial, at 114 centers in the UK, compared less than annual mammography with annual mammography among women aged 50 years or older and 3 years after curative surgery. Women were randomized to annual mammography (n=2618) or less frequent mammography (n=2617; every two years after breast conserving therapy; every three years after mastectomy). With a median duration of follow-up of 5.7 years (IQR 5.0-6.0; 8.7 years post curative surgery), 343 women died, including 116 who died of breast cancer: 61 in the annual mammography group and 55 in the less frequent mammography group. Less frequent mammography was noninferior to annual mammography for breast cancer-specific survival, recurrence-free survival, and overall survival. The authors conclude that among patients aged 50 years or older and at 3 year post diagnosis, less frequent mammography should be considered.