RESUMEN
PURPOSE: Cisplatin, an effective medication for metastatic breast cancer (MBC), is recommended to be applied at the dose of 75 mg/m2 on day 1 every 3 weeks. However, the 75 mg/m2 schedule is often associated with a variety of side effects (such as vomiting and kidney toxicity), and time-consuming hydration treatment is usually needed. Divided dose (25 mg/m2 on day 1-3) without hydration is an alternative. This study aimed to compare the efficacy and toxicity profiles between these two dosage regimens. METHODS: Patients with MBC treated with cisplatin-based regimens in Fudan University Shanghai Cancer Center between December 2008 and June 2019 were retrospectively analyzed. Objective response rate (ORR), progression-free survival (PFS), and toxicity profiles were analyzed. RESULTS: 227 patients receiving a 1-day schedule and 256 patients receiving a 3-day schedule were included. Median PFS was 6.68 (5.66-7.70) months for patients in the 1-day schedule group and 6.70 (5.89-7.52) months for patients in the 3-day schedule group. There was no statistically significant difference in PFS between the two treatment groups (hazard ratio, 0.942; 95% CI 0.759 to 1.170; P = 0.589). The ORRs were comparable between the two groups. ORRs were 44.9% in 1-day schedule group and 44.5% in 3-day schedule group, respectively (P = 0.929). Compared with patients in the 3-day schedule group, patients in the 1-day schedule group experienced higher rates of chemotherapy-induced nausea and vomiting (CINV) (139 [61.2%] vs. 132 [51.6%], P = 0.033). The risk of hypomagnesaemia was also significantly higher (43.2% vs. 28.3%, P = 0.016) among patients receiving 1-day schedule (without magnesium supplementation). No other differences in adverse events were observed between the two groups. CONCLUSIONS: Cisplatin given at three divided doses with no hydration in MBC is a less toxic (less CINV and hypomagnesaemia) schedule with comparable efficacy. Thus, it may be a good alternative for one full-dose (75 mg/m2) schedule.