Concurrent Chemoradiotherapy vs Radiotherapy Alone in Stage II Nasopharyngeal Carcinoma: Phase III Randomized Trial

BACKGROUND: Concurrent chemoradiotherapy (CCRT) has been shown to improve outcomes for stage III-IV nasopharyngeal carcinoma (NPC) patients compared with radiotherapy (RT) alone, but the effectiveness of the combined therapy for stage II NPC patients is unknown. METHODS: Patients with Chinese 1992 stage II NPC were randomly assigned to receive either RT alone (n = 114) or CCRT (n = 116). The CCRT patients were given concurrent cisplatin (30 mg/m(2) on day 1) weekly during RT. The primary endpoint was overall survival (OS). Secondary endpoints were progression-free survival (PFS), distant metastasis-free survival, and locoregional relapse-free survival. All patients were analyzed by the intent-to-treat principle. The Cox proportional hazards model was used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) and in multivariable analyses to test the independent statistical significance of treatment intervention. Toxic effects and the response to treatment were analyzed using the χ(2) test. All statistical tests were two-sided. RESULTS: With a median follow-up of 60 months, adding chemotherapy statistically significantly improved the 5-year OS rate (94.5% vs 85.8%; HR of death = 0.30, 95% CI = 0.12 to 0.76; P = .007), PFS (87.9% vs 77.8%; HR of progression = 0.45, 95% CI = 0.23 to 0.88; P = .017), and distant metastasis-free survival (94.8% vs 83.9%; HR of distant relapse = 0.27, 95% CI = 0.10 to 0.74; P = .007); however, there was no statistically significant difference in the 5-year locoregional relapse-free survival rate (93.0% vs 91.1%; HR of locoregional relapse = 0.61, 95% CI = 0.25 to 1.51; P = .29). Multivariable analysis showed that the number of chemotherapy cycles was the only independent factor that was associated with OS, PFS, and distant control in stage II NPC. The CCRT arm experienced statistically significantly more acute toxic effects (P = .001), although the rate of late toxic effects did not increase statistically significantly. CONCLUSION: Concurrent chemotherapy and radiotherapy is associated with a considerable survival benefit for patients with stage II NPC.