A randomized trial (MA.17R) of extending adjuvant letrozole for 5 years after completing an initial 5 years of aromatase inhibitor therapy alone or preceded by tamoxifen in postmenopausal women with early-stage breast cancer.

LBA1 Background: Five years of aromatase inhibitor (AI) therapy either as up-front treatment or after 2-5 years of tamoxifen has become the standard of care for postmenopausal women with hormone receptor positive early breast cancer. Extending treatment with an AI to 10 years may further reduce the risk of breast cancer recurrence. Methods: We conducted a double-blind, placebo-controlled trial (Canadian Cancer Trials Group …