Screening women from age 40 would reduce breast cancer mortality
Breast cancer screening is currently offered to UK women aged 50-70, but uncertainty exists over whether to start screening at a younger age. In a paper published in Lancet Oncology on 12 August 2020, researchers from Queen Mary’s Wolfson Institute, with an international group of collaborators, present the 23-year follow-up results of the UK Breast Screening Age Trial. Their results show that, despite recognised problems inherent in screening younger women, annual mammography from age 40 would reduce breast cancer mortality, with no appreciable increase in overdiagnosis. There was a substantial and significant reduction of around 25% in breast cancer mortality in the first ten years, and although this reduction attenuated thereafter, the absolute benefit remained roughly constant at one death prevented per 1,000 women screened.
Between 1990 and 1997, the UK Breast Screening Age Trial randomised over 150,000 UK women aged 39-41 to receive either annual mammography, or usual NHS screening commencing at age 50. Uniquely, this trial specifically recruited subjects at ages 39-41, so all trial screening took place before age 50. The primary outcome was mortality from breast cancers diagnosed prior to first NHSBSP screen, based on an intention to treat analysis. The total years of life saved from breast cancer in the intervention group was estimated as 620, corresponding to 11·5 years saved per 1,000 women invited.
The authors recommend further research to clarify whether progress in early detection technology and treatment of breast cancer might modify the screening-related reduction in mortality in the 40-49 age group.
The study was supported by funding from the National Institute for Health Research Health Technology Assessment programme, and the American Cancer Society.
Effect of mammographic screening from the age of 40 years on breast cancer mortality (UK Age Trial): final results of a randomised, controlled trial. Stephen W Duffy, Daniel Vulkan, Howard Cuckle, Dharmishta Parmar, Shama Sheikh, Robert A Smith, Andrew Evans, Oleg Blyuss, Louise Johns, Ian O Ellis, Jonathan Myles, Peter D Sasieni, Sue M Moss. Lancet Oncol, 12 August 2020.