Development of a web-based prognostic model to quantify the survival benefit of cumulative cisplatin dose during concurrent chemoradiotherapy in childhood nasopharyngeal carcinoma.

Abstract

To quantify and predict the survival benefits of cumulative cisplatin dose during concurrent chemoradiotherapy (CC-CCD) in children and adolescents with locoregionally advanced nasopharyngeal carcinoma (CA-LANPC). Patients with CA-LANPC who received first-line neoadjuvant chemotherapy (NAC) followed by concurrent chemoradiotherapy (CCRT) between September 2007 and April 2018 were evaluated. Recursive partitioning analyses (RPAs) helped identify the ideal thresholds of CC-CCD on disease-free survival (DFS). We then developed a web-based predictive model to quantify the survival benefit of CC-CCD for CA-LANPC. In total, 139 patients were eligible for the analysis. The median CC-CCD was 162 mg/m² (IQR, 138-192 mg/m²). The optimum cut-off point of CC-CCD was 160 mg/m² for DFS. Hence, we selected 160 mg/m² as the cut-off to classify CA-LANPC into either high or low CC-CCD groups for survival analysis. The 5-year DFS rates were 91.6% in the high (≥160 mg/m²) CC-CCD group and 77.8% in the low (<160 mg/m²) CC-CCD group (P = 0.011). Multivariate analysis indicated CC-CCD (HR, 0.34; 95%CI, 0.13-0.87; P = 0.024), T stage (HR, 3.72; 95%CI, 1.35-10.22; P = 0.011), and EBV DNA (HR, 3.00; 95%CI, 1.00-8.97; P = 0.049) were independent prognostic factors and were incorporated into the prognostic model. N stage was also included due to its clinical importance. The predictive model was demonstrably accurate (C-index, 0.741) when predicting 5-year DFS rates. We built a predictive model to quantify the survival benefit of CC-CCD for CA-LANPC treated with NAC plus CCRT. This tool may improve individual treatment consultations and facilitate evidence-based decision-making.