Adherence to initial adjuvant anastrozole therapy among women with early-stage breast cancer.

Purpose: Previous research evaluating adherence to tamoxifen therapy among women with early-stage breast cancer has revealed adherence estimates ranging from 25% to 96%. No previous studies have focused on adherence to adjuvant aromatase inhibitors.

Methods: We used longitudinal claims data from three large commercial health programs to estimate adherence with anastrozole therapy among women with early-stage breast cancer.