Nine weeks versus six months of adjuvant trastuzumab in HER2-positive breast cancer: 3-year disease-free survival results.

Abstract

e12530 Background: A total of 12 months adjuvant trastuzumab is still the optimal choice for patients with HER2-positive early breast cancer. However, the shorter course of 9 weeks may be considered as a cost-effective and safe option in developing countries such as Syria. Purpose: We aimed at investigating whether short-course 9-week adjuvant Trastuzumab is non-inferior to 6-month treatment at Albairouni University Cancer Center. The primary endpoint was disease-free survival (DFS). The secondary objective was assessing toxicities, especially cardiotoxicity. Methods: Patients with HER2-positive stage I-IIIC breast cancer were assigned to receive either 9 weeks or 6 months of trastuzumab in combination with adjuvant chemotherapies (sequentially). The 9-week group; 90 patients received trastuzumab intravenously (loading dose 4 mg/kg; then 2mg/kg weekly), whereas in the 6-month group; 157 patients, trastuzumab was delivered every 3 weeks intravenously (loading dose 8 mg/kg then 6 mg/kg). The LVEF was measured pretreatment and every 3 months afterwards. Results: 3-year DFS was 71.87% in the 9-week group versus 76.43% in the 6-month group, (Non-significant). No obvious side effects have been noticed during the follow-up period in the 9-week group. Congestive heart failure was reported in 2.55% of patients in the 6-month group. Conclusions: Short-course 9-week adjuvant trastuzumab is less effective than 6 months of treatment, with less cardiotoxicity. The short course could be considered in patients with heart disease and low risk of recurrence.