Current Perspective of Chemotherapy in Metastatic Breast Cancer: New Evidence From Select Bc Trial

Abstract

While living with metastatic breast cancer presents challenges, there are many options available for chemotherapy. The goal for many patients is to stay on treatment as long as it successfully relieves symptoms and slows tumor growth. Taxanes have been a mainstay of chemotherapy for patients with metastatic breast cancer at the cost of side effects, which sometimes are not trivial. TS-1 is an orally available 5-fluorouracil derivative, and multiple clinical trials have demonstrated its clinical efficacy and tolerability. Recently, a phase III open-label randomized controlled trial was conducted in Japan to test the non-inferiority of TS-1 in terms of overall survival (OS) to taxanes at first line in patients with metastatic breast cancer. Previously untreated metastatic breast cancer patients were assigned to either taxanes or TS-1 in the study. The primary endpoint of the study was OS, and secondary endpoints include time to treatment failure (TTF) and health-related QOL. Non-inferiority of TS-1 to taxanes was demonstrated in OS and TTF with statistical significance, and toxicity profile of TS-1 was mild to maintain the QOL of the patients in the study. Chemotherapy for breast cancer should focus on maintaining a patient's QOL while minimizing side effects, and roles of oral fluoropyrimidine and conventional agents such as taxanes and anthracyclines in breast cancer chemotherapy will be discussed at the conference.