Optimal cumulative cisplatin dose during concurrent chemoradiotherapy among children and adolescents with locoregionally advanced nasopharyngeal carcinoma: A real-world data study.

ABSTRACT

PURPOSE: To identify an optimal cumulative cisplatin dose along with concurrent chemoradiotherapy (CC-CCD) for children and adolescents with locoregionally advanced nasopharyngeal carcinoma (CALANPC) using real-world data. MATERIALS AND METHODS: Using an NPC-specific database at our center, 157 patients younger than 19 years old with non-disseminated CALANPC and receiving neoadjuvant chemotherapy (NAC) plus cisplatin-based concurrent chemoradiotherapy (CCRT) were enrolled. Confounding factors were controlled by conducting propensity score matching analysis. Primary endpoints include disease-free survival (DFS) and distant metastasis-free survival (DMFS). RESULTS: The optimal threshold for CC-CCD with respect to DFS was 160 mg/m2 based on recursive partitioning analyses (RPA). Therefore, a uniform threshold of 160 mg/m2 (≥160 vs. <160 mg/m2) was selected to classify patients between high and low CC-CCD groups for survival analysis. Patients receiving low CC-CCD showed a significant decrease in 5-year DFS (76.6% vs 91.3%; P = 0.006) and DMFS (81.3% vs 93.5%; P = 0.009) compared to those receiving high CC-CCD. Multivariate analyses indicated that high CC-CCD as an favorable prognostic influence for DFS (P = 0.007) and DMFS (P = 0.008). Further matched analysis identified 65 pairs in both high and low CC-CCD groups. In the matched cohort, high CC-CCD was still identified as a favorable factor for prognosis in DFS (HR, 0.23; 95% CI, 0.08-0.70; P = 0.010) and DMFS (HR, 0.23; 95% CI, 0.06-0.82; P = 0.023). CONCLUSION: CC-CCD exerts significant treatment effects and 160 mg/m2 CC-CCD may be adequate to provide antitumor effects for CALANPC receiving NAC plus CCRT.