Radiation risk of breast screening in England with digital mammography

Objective: To estimate the risks and benefits of breast screening in terms of number of deaths due to radiation-induced cancers and the number of lives saved owing to modern screening in the National Health Service Breast Screening Programme (NHSBSP) in England. Methods: Radiation risk model, patient dose data and data from national screening statistics were used to estimate the number of deaths due to radiation-induced breast cancers in the NHSBSP in England. Dose and dose effectiveness factors (DDREFs) equal to one and two were assumed. The breast cancer mortality reduction in the invited population due to screening and the percentage of females diagnosed with symptomatic breast cancer, who die from breast cancer, were collated from the literature. The number of lives saved owing to screening was calculated. Results: Assuming, a total of 1,770,436 females between the ages of 50-70 years were screened each year, and a breast cancer mortality reduction of 20% due to screening in the invited population, the number of screen-detected cancers were 14,872 annually, resulting in 1071 lives saved. Conversely, for the same mortality reduction, the number of radiation-induced cancers was 36 and 18 for DDREFs of 1 and 2, respectively. This resulted in seven and three deaths due to radiation-induced cancers annually for DDREFs of 1 and 2, respectively. The ratios of lives saved owing to screening to radiation-induced cancerswere 30: 1 and 60: 1 for DDREFs of 1 and 2. The ratios of lives saved owing to screening to deaths due to radiation-induced cancers were 156: 1 and 312 : 1 for DDREFs of 1 and 2. For the 1.8% of the screening population with very thick breasts, the latter ratios decrease to 94: 1 and 187 : 1 for DDREFs of 1 and 2. Conclusion: The breast cancer mortality reduction due to screening greatly outweighs the risk of death due to radiation-induced cancers. Advances in knowledge: Estimation of the radiation risk for modern breast screening in England using digital mammography.