Do BIG1-98 and ZOFAST demand a change in guidelines for endocrine therapy?

Excerpt

The BIG1-98 trial, involving over 8,000 postmenopausal women with hormone receptor-positive early breast cancer, was a four-arm trial of adjuvant endocrine therapy for early breast cancer comparing 5 years of tamoxifen treatment versus 5 years of letrozole treatment versus 2 years of tamoxifen then switch to letrozole treatment versus 2 years of letrozole then switch to tamoxifen treatment. The initial results of the trial, which compared only the upfront tamoxifen and letrozole arms, showed a small but highly statistically significant disease-free survival (DFS) advantage in favour of letrozole with a hazard ratio of 0.81 and an absolute 4-year improvement in DFS of 2.7% [1]. …