Acomparison of letrozole and anastrozole followed by letrozole in breast cancer patients

Abstract

Background: We previously studied the noninferiority of anastrozole (ANZ) versus ANZ followed by letrozole (A-LTZ) due to reimbursement policy. We found that patients with A-LTZ had better overall survival (OS) than did patients with ANZ alone. This study aimed to prove that patients with A-LTZ also had better OS than patients with letrozole (LTZ) alone. Methods: All medical records of the breast cancer patients taking LTZ with or without ANZ between 2004 and 2013 were reviewed. All patients were divided into two groups: the LTZ group included patients treated with LTZ alone, and the A-LTZ group included patients treated with ANZ who were automatically changed to LTZ due to change of the reimbursement policy. Results: From 359 cases, there were 179 cases in the LTZ group and 180 cases in the A-LTZ group. The mean age of patients in the LTZ group was 53.7 years and in the A-LTZ group was 54.2 years. The distribution of clinical stages among the LTZ group versus the A-LTZ group was 21 versus 4 (stage 1), 86 versus 116 (stage 2), 55 versus 46 (stage 3), and 17 versus 14 (stage 4), respectively. Among the LTZ patients, 63.7% took aromatase inhibitor monotherapy and 36.3% had a switching strategy, while in the A-LTZ group, 53.9% took AI monotherapy and 46.1% had a switching strategy. OS of the A-LTZ group was longer than that of the LTZ group. Conclusion: The patients in A-LTZ, taking ANZ followed by LTZ had better OS than those in LTZ, taking LTZ alone.