Extending Adjuvant Aromatase-Inhibitor Therapy to 10 Years

To the Editor: In the MA.17R trial by Goss et al. (July 21 issue), 1 the rate of overall survival was not higher among women who received letrozole once a day for 5 years (accounting for more than 1800 pills) than among those who received placebo. The rates of contralateral breast cancer and of local, regional, or distant recurrence were lower among the women who received letrozole than among those who received placebo. However, at a median of 6.3 years of follow-up, the rate of distant life-threatening metastases in the letrozole group was only 1.1 percentage points lower than the rate . . .