Canadian National Breast Screening Study: 1. Breast cancer detection and death rates among women aged 40 to 49 years.

Abstract

The study was internally valid, and there was no evidence of randomization bias. Screening with yearly mammography and physical examination of the breasts detected considerably more node-negative, small tumours than usual care, but it had no impact on the rate of death from breast cancer up to 7 years' follow-up from entry.