Significance of chemotherapy for older patients with nasopharyngeal carcinoma in the intensity-modulated radiotherapy era: A propensity score matching analysis

Introduction: This study aimed to evaluate the survival and prognosis of older patients with nasopharyngeal carcinoma (NPC) who received intensity-modulated radiotherapy (IMRT) alone versus IMRT plus chemotherapy using propensity score matching (PSM).Materials and Methods: We enrolled 841 older patients with NPC aged 60 years and above without metastasis receiving IMRT alone or chemoradiotherapy from 2012 to 2019. The comorbidity was assessed by adult co-morbidity evaluation (ACE-27). PSM (1:3 ratio) was conducted between the two treatment groups based on four clinical factors including age, T-stage, N-stage, and ACE-27. Differences in overall survival (OS) and cancer-specific survival (CSS) were analyzed by the Kaplan-Meier method and Cox proportional hazard model.Results: A total of 841 patients with NPC were included in the study, there were 94 patients in the IMRT alone group and 747 patients in the chemoradiotherapy (CRT) group. After a 1:3 ratio PSM, 89 patients underwent IMRT alone and 223 patients underwent CRT. The baseline analysis showed an insignificant difference after PSM (P > 0.05). In multivariate analysis, we found that ACE-27 (>2) was associated with worse five-year OS and CSS (HR = 1.994, 95%CI: 1.276-3.116, P = 0.002; HR = 1.849, 95%CI: 1164-2.935, P = 0.009, respectively). Chemotherapy was an independent prognosticator of better five-year OS and CSS (HR = 0.333, 95%CI: 0.213-0.552, P < 0.001; HR = 0.327, 95%CI: 0.204-0.524, P < 0.001, respectively). In terms of subgroup analysis, chemotherapy was a statistically beneficial predictor for stage III-IV patients (P < 0.05), but no sig-nificant difference in stage II patients (P > 0.05). About the adverse events, the incidence of hepatotoxicity (P = 0.002), neutropenia (P < 0.001), anemia (P < 0.001), and thrombocytopenia (P < 0.001) were significantly higher in the CRT group.Discussion: Combined modality therapy was associated with improved five-year OS and CSS in older adults with stage III-IV NPC, but was not associated with improved survival over IMRT alone in patients with stage II disease. Risk factors including T3-4 disease, positive lymph nodes, ACE-27 score > 2, and IMRT alone were were associated with worse OS and CSS. There was a significantly higher incidence of hepatotoxicity and blood toxicity in the CRT group.