A case‐control study of the efficacy of a non‐randomized breast cancer screening program in florence (Italy)

Abstract

In a rural area near Florence a population-based screening program for breast cancer was started in 1970, offering a mammography test every 2.5 years to all women between 40 and 70 years of age. In order to evaluate the efficacy of this program a case-control study has been carried out comparing the screening history of all women who died from breast cancer in this area in the years 1977–1984, and who had been diagnosed after the start of the program, with that of a matched group of living controls. The case-control study showed that the overall O.R. of dying from breast cancer in the study period for “screened” versus “never-screened” women was 0.53 (95% C.I. = 0.29–0.95). After evaluation of other variables as potential confounders the adjusted O.R. estimates were respectively 0.57 (95% C.I. = 0.35–0.92) and 0.32 (95% C.I. = 0.20–0.52) for women screened only once or at least twice. No significant protective effect was shown for women below the age of 50 years.