The risk of radiation-induced breast cancers due to biennial mammographic screening in women aged 50-69 years is minimal

Abstract

Background: The main aim of mammographic screening is to reduce the mortality from breast cancer. However, use of ionizing radiation is considered a potential harm due to the possible risk of inducing cancer in healthy women.

Purpose: To estimate the potential number of radiation-induced breast cancers, radiation-induced breast cancer deaths, and lives saved due to implementation of organized mammographic screening as performed in Norway.

Material and methods: We used a previously published excess absolute risk model which assumes a linear no-threshold dose-response. The estimates were calculated for 100,000 women aged 50-69 years, a screening interval of 2 years, and with an assumed follow-up until the age of 85 or 105 years. Radiation doses of 0.7, 2.5, and 5.7 mGy per screening examination, a latency time of 5 or 10 years, and a dose and dose-rate effectiveness factor (DDREF) of 1 or 2 were applied.

Results: The total lifetime risk of radiation-induced breast cancers per 100,000 women was 10 (95% CI: 4-25) if the women were followed from the ages of 50 to 85 years, for a dose of 2.5 mGy, a latency time of 10 years, and a DDREF of 1. For the same parameter values the number of radiation-induced breast cancer death was 1 (95% CI: 0-2). The assumed number of lives saved is approximately 350.

Conclusion: The risk of radiation-induced breast cancer and breast cancer death due to mammographic screening is minimal. Women should not be discouraged from attending screening due to fear of radiation-induced breast cancer death.

Keywords: Breast; adults; mammography; radiation effect; radiation safety; screening.