Concurrent Chemoradiotherapy versus Intensity-modulated Radiotherapy Alone for Elderly Nasopharyngeal Carcinoma Patients with Pre-treatment Epstein-Barr Virus DNA: A Cohort Study in an Endemic Area with Long-term Follow-up.

Purpose: To date, no guidelines exist for elderly nasopharyngeal carcinoma (NPC) patients (60 years of age or older) due to a lack of prospective clinical trials. This study evaluated the efficacy of concurrent chemotherapy (CCRT) for NPC in elderly patients treated with intensity-modulated radiotherapy (IMRT). Methods: Patients were identified from a prospectively maintained database. A total of 198 consecutive cases of elderly patients with NPC receiving IMRT, including 103 patients treated with IMRT plus CCRT and 95 patients treated with IMRT alone, were analysed from January 2002 to December 2013. Multivariate analysis (MVA) using the Cox proportional hazards model and propensity score analysis (PSA) were performed for overall survival (OS) and disease-free survival (DFS). Finally, sensitivity analysis was performed. Results: The median follow-up time was 55.3 months (range, 3-135.6 months). In the entire cohort, both MVA and PSA models showed that compared with IMRT alone, IMRT plus CCRT significantly improved survival (hazard ratio [HR] 2.143, 95% confidence interval [95% CI] 1.180-3.890; HR 1.961, 95% CI, 1.117-3.443, for OS and DFS, respectively). Similar results were found in the subgroups with high levels of Epstein-Barr virus (EBV) DNA, except in the low-EBV-DNA cohort. The total rates of severe acute toxicity, including leukopenia, neutropenia, stomatitis, and emesis, were significantly higher in the IMRT+CCRT group than in the IMRT-alone group (P < 0.001) but were similar to the rates of severe late toxicity (P = 0.818). Sensitivity analysis confirmed the robustness of our analysis. Conclusions: In the era of IMRT, CCRT retained survival benefits at high EBV DNA levels but not at low EBV DNA levels for elderly NPC patients. Randomized clinical trials are needed to confirm our findings.