FIG A1.

Kaplan-Meier estimates of cumulative breast cancer incidence by histologic type (atypical ductal hyperplasia [ADH], lobular carcinoma in situ [LCIS], ductal carcinoma in situ [DCIS]) regardless of treatment with tamoxifen. Numbers in parentheses represent the number of events that occurred within each time interval by treatment arm. The log-rank test was used to draw inferences. The hazard ratios (HRs) for LCIS versus ADH and DCIS versus ADH were estimated from a Cox proportional hazards regression model adjusted for treatment arm; the HR of the treatment effect (data not shown), adjusted for the histologic type, was 0.48 (95% CI, 0.25 to 0.91). In the overall intention-to-treat population, there were 42 breast cancer events (three in the ADH group, 31 in the DCIS group, and eight in the LCIS group). The 5-year cumulative incidence rate of breast cancer was 3.2% (95% CI, 1.0% to 9.5%) in the ADH group, 9.0% (95% CI, 6.1% to 13.0%) in the DCIS group, and 18.0% (95% CI, 9.2% to 33.4%) in the LCIS group. The HRs compared with ADH are adjusted for treatment arm.