Comparison of induction chemotherapy combined with concurrent chemoradiotherapy versus concurrent chemoradiotherapy alone in Lymph-Node-Stage Nasopharyngeal Carcinoma based on propensity score-matching

PURPOSE:To explore the role of induction chemotherapy (IC) followed by concurrent chemoradiotherapy (CCRT) versus CCRT alone in patients diagnosed with N3 nasopharyngeal carcinoma (NPC). PATIENTS AND METHODS:A total of 787 patients with newly diagnosed N3 NPC treated with IC + CCRT or CCRT alone were included. Progression-free survival (PFS) was the primary endpoint. We balanced variables using propensity score matching (PSM). Kaplan-Meier curves with log-rank tests were applied to evaluate the survival condition of each group. Independent prognostic factors were identified using the Cox regression analysis. RESULTS:PSM assigned 228 patients to IC + CCRT and CCRT alone groups. Survival analysis for the matched data set showed that IC + CCRT achieved better survival outcomes compared with CCRT alone, and significant difference was observed in 5-year PFS [74.8% (95%CI 69.2 ∼ 80.9%) vs 65.4% (95%CI 59.4 ∼ 72.0%), P = 0.008], 5-year OS [(77.4%(95%CI 71.9 ∼ 83.3%) vs66.3%(95%CI 60.3 ∼ 72.9%), P = 0.005)] and 5-year distant metastasis-free survival (DMFS)[(81.8%(95%CI 76.7 ∼ 87.2%) vs72.4%(95%CI 66.7 ∼ 78.7%), P = 0.007)] between the two treatment groups. In multivariate analysis, IC + CCRT remained an independent protective factor for PFS (adjusted HR, 0.603; 95% CI, 0.433-0.841; P = 0.003), OS (adjusted HR, 0.568; 95% CI, 0.406-0.793; P < 0.001), and DMFS (adjusted HR, 0.541; 95% CI, 0.364-0.805; P = 0.002). CONCLUSION:More chemotherapy should be considered in patients with N3 NPC because of its ability to improve survival time. This could be from the use of IC or adjuvant metronomic chemotherapy.