Long-term outcomes of chemoradiotherapy versus radiotherapy alone in patients with intermediate-risk nasopharyngeal carcinoma: a population-based analysis.

purposeTo investigate the efficacy of chemotherapy among intermediate-risk (stage II/T3N0) nasopharyngeal carcinoma (NPC) patients receiving radiotherapy (RT).

methodsWe identified stage II/T3N0 NPC patients who received radiotherapy with or without chemotherapy from the Surveillance, Epidemiology and End Results database (2004-2019). Overall survival (OS) and cancer-specific survival (CSS) were assessed using the Kaplan-Meier method with log-rank test and Cox proportional hazards models to evaluate the efficacy of chemotherapy. Subgroup analysis was also conducted based on the baseline characteristics. Propensity score matching (PSM) was performed to balance the intergroup covariates.

resultsA total of 1623 patients were enrolled in the study, 1444 received chemoradiotherapy (CRT) and 179 received RT alone. CRT, compared to RT alone, was independently associated with a better OS (HR 0.57, 95% CI 0.45-0.71) and CSS (HR 0.55, 95% CI 0.39-0.79). After PSM, similar results were obtained, and CRT was superior to RT alone in terms of OS (HR 0.60, 95% CI 0.39-0.92) and CSS (HR 0.60, 95% CI 0.40-0.91). Subgroup analysis revealed that OS benefits from CRT were mainly observed in T0-2N1(HR 0.51, 95% CI 0.38-0.70) and T3N0 (HR 0.64, 95% CI 0.42-0.98) rather than T2N0 (HR 1.00, 95% CI 0.51-1.94). Interestingly, after PSM, OS benefits were still seen in T0-2N1 (HR 0.44, 95% CI 0.24-0.82), while not seen in T2N0 (HR 1.83, 95% CI 0.56-5.97) and T3N0 (HR 0.56, 95% CI 0.28-1.12).

conclusionFor T0-2N1 NPC patients, CRT was superior to RT alone with better survival, whereas, for T2-3N0 patients, CRT was comparable to RT alone. Prospective large studies should be encouraged to verify the results.