Final updated results of the NRG Oncology/NSABP Protocol P-2: Study of Tamoxifen and Raloxifene (STAR) in preventing breast cancer.

1500 Background: NSABP P-2 (STAR) was a randomized, double-blinded trial of tamoxifen vs raloxifene for the reduction of breast cancer incidence. The initial report from 2006 found raloxifene to be as effective as tamoxifen in preventing invasive breast cancer, but with fewer associated toxicities. In 2010 updated results indicated that raloxifene retained 76% of the effectiveness of tamoxifen in preventing invasive breast cancer and remained less toxic. Methods: May 31, 2012, STAR was permanently closed to followup. This current and final update is based on data through the end of followup for invasive and noninvasive breast cancer, other cancers, vascular events, and deaths. The final analysis comprises the same 19,490 women (9736 in the tamoxifen group and 9754 in the raloxifene group) as the 2010 update report. The median time of followup as of May 31, 2012, was 9.7 yrs. Results: Similar to the previous update, raloxifene remains less effective in preventing invasive breast cancer than tamoxifen (RR =...