Figure 2.

Recurrence-free interval (RFI) and overall survival (OS) by receipt of radiotherapy (RT). Recurrence-free interval (A) and overall survival (B) were determined using a Cox model adjusted for patient age, tumor grade (low, moderate, high, or unknown), ER/PR status (ER+ and PR+ or other), HER2 (negative or unknown), type of initial hormonal treatment (tamoxifen, aromatase inhibitors, or other), tumor size, trial, and Oncotype DX recurrence score. Evaluated at mean age, tumor size, Oncotype DX recurrence score, and tamoxifen hormonal treatment, low grade, ER+/PR+ status, and in studies where radiotherapy was randomized. P values for rate differences are based on a two-tailed Z test.