The impact of cumulative dose of cisplatin on outcome of patients with head and neck squamous cell carcinoma.

Despite the wide use of cisplatin-based concomitant chemoradiotherapy (CCRT) for head and neck squamous cell carcinoma (HNSCC), data on the optimal regimen and cumulative dose are scarce and frequently conflicting. We aimed to evaluate the compliance and the impact of the cumulative dose of cisplatin on overall survival (OS), disease-free survival (DFS), loco-regional control (LRC), and distant-metastasis-free survival (DMFS) in a retrospective study. Between 2008 and 2015, 279 patients with HNSCC scheduled for CCRT (three courses of 3-week 100 mg/m2 cisplatin) were identified. Of the whole group, 14% did not receive any cisplatin and 26% received daily cisplatin. In patients planned for three courses (n = 167), 56% received 3, 20% received 2, and 24% received one course. After median follow-up of 31.6 months, the actuarial OS, DFS, LRC, and DMFS rates at 3 years for patients received cumulative dose of ≥200 mg/m2 were significantly better compared to those received <200 mg/m2; 74 vs. 51% for OS, 73 vs. 49% for DFS, 80 vs. 58% for LRC (p < 0.001), and 85 vs. 76% for DMFS (p = 0.034). At multivariate analysis, the cumulative cisplatin dose (≥200 vs. <200 mg/m2) was significantly predictive for OS (HR 2.05; 95% CI 1.35-3.13, p = <0.001). Borderline GFR (60-70 mL/min) at baseline predicts compliance for ≥two courses (p = 0.003). In conclusion, considerable proportion of patients did not receive all pre-planned courses of cisplatin. Patients receiving cumulative cisplatin dose ≥200 mg/m2 had significantly better outcome than those receiving <200 mg/m2 and cumulative dose <200 mg/m2 might even be detrimental. These findings increased the bulk of slowly growing evidence on the optimal cumulative dose of cisplatin. Baseline GFR might predict compliance.