Publication Abstract

Authors: Tabár L, Chen HH, Fagerberg G, Duffy SW, Smith TC

Title: Recent results from the Swedish Two-County Trial: the effects of age, histologic type, and mode of detection on the efficacy of breast cancer screening.

Journal: J Natl Cancer Inst Monogr (22):43-7

Date: 1997

Abstract: The effect of mammographic screening in reducing mortality from breast cancer is known to be smaller and more delayed in women aged 40-49 than in women over 50. In this study, we investigated how these phenomena relate to histology-specific breast cancer incidence and mortality. The data are from 2,468 women with breast cancer who participated in the Swedish Two-County Trial. The overall relative breast cancer mortality of invited to noninvited women aged 40-49 was 0.87, and the relative mortality from poorly differentiated (grade 3) ductal carcinoma was 0.95. These results were not statistically significant. The corresponding relative risks for invited women aged 50-74 were a statistically significant 0.65 and 0.61. We conclude that in this trial, with a two-year interscreening interval, the smaller and later effect of invitation to screening on breast cancer mortality in women 40-49 years old is due to the failure of screening to reduce mortality from grade 3 ductal carcinoma in this age group.