Results of letrozole in postmenopausal women after tamoxifen treatment for advanced breast cancer.

AIM To analyze overall and progression-free survival after letrozole in postmenopausal women with advanced breast cancer who failed after tamoxifen therapy. MATERIALS AND METHODS This is a retrospective analysis of 95 patients with breast cancer who were postmenopausal and had failed after tamoxifen therapy. Dose of letrozole was 2.5 mg daily until disease progressed. Patients had estrogen receptor- and/or progesterone receptor-positive tumors or both receptors were unknown. One complete course of (6 cycles) chemotherapy for metastatic disease was allowed. The primary end point was time to progression (TTP). Secondary end points included overall objective response rate (ORR), its duration, time to treatment failure (TTF), overall survival and tolerability. RESULTS Median TTP was 10 months. ORR was 21% with complete response rate of 9%. Nine patients died of disease during treatment. Median overall survival was 36 months. Median time to response was three months and median duration of response was 13 months. Time to chemotherapy was 13.5 months and TTF was 9.3 months. Treatment failure was seen in 76% of patients. Disease progression was the main cause for treatment failure. Treatment was well-tolerated by all patients. CONCLUSION This retrospective analysis shows that letrozole is quite effective as second line therapy in postmenopausal patients with advanced breast cancer who had failed after tamoxifen therapy.