Efficacy and Safety of Locoregional Radiotherapy With Chemotherapy vs Chemotherapy Alone in De Novo Metastatic Nasopharyngeal Carcinoma

Importance: The role of locoregional radiotherapy in patients with de novo metastatic nasopharyngeal carcinoma (mNPC) is unclear. Objective: To investigate the efficacy and safety of locoregional radiotherapy in de novo mNPC. Design, Setting, and Participants: Patients with biopsy-proven mNPC, who demonstrated complete or partial response (RECIST v1.1) following 3 cycles of cisplatin and fluorouracil chemotherapy, were enrolled. Eligible patients were randomly assigned (1:1) to receive either chemotherapy plus radiotherapy or chemotherapy alone. Overall, 126 of 173 patients screened were eligible to the study, and randomized to chemotherapy plus radiotherapy (n = 63) or chemotherapy alone (n = 63). Median (IQR) follow-up duration was 26.7 (17.2-33.5) months. Interventions: The chemotherapy regimens were fluorouracil continuous intravenous infusion at 5 g/m2 over 120 hours and 100 mg/m2 intravenous cisplatin on day 1, administered every 3 weeks for 6 cycles. Patients assigned to the chemotherapy plus radiotherapy group received intensity-modulated radiotherapy (IMRT) after chemotherapy. Main Outcomes and Measures: The primary end point of the study was overall survival (OS). The secondary end point was progression-free survival (PFS) and safety. Results: Overall, 126 patients were enrolled (105 men [83.3%] and 21 women [16.7%]; median [IQR] age, 46 [39-52] years). The 24-month OS was 76.4% (95% CI, 64.4%-88.4%) in the chemotherapy plus radiotherapy group, compared with 54.5% (95% CI, 41.0%-68.0%) in the chemotherapy-alone group. The study met its primary end point of improved OS (stratified hazard ratio [HR], 0.42; 95% CI, 0.23-0.77; P = .004) in favor of chemotherapy plus radiotherapy. Progression-free survival was also improved in the chemotherapy plus radiotherapy group compared with the chemotherapy-alone group (stratified HR, 0.36; 95% CI, 0.23-0.57). No significant differences in acute hematological or gastrointestinal toxic effects were observed between the treatment arms. The frequency of acute grade 3 or higher dermatitis, mucositis, and xerostomia was 8.1%, 33.9%, and 6.5%, respectively, in the chemotherapy plus radiotherapy group. The frequency of late severe grade 3 or higher hearing loss and trismus was 5.2% and 3.4%, respectively, in the chemotherapy plus radiotherapy group. Conclusions and Relevance: In this randomized clinical trial, radiotherapy added to chemotherapy significantly improved OS in chemotherapy-sensitive patients with mNPC. Trial Registration: ClinicalTrials.gov Identifier: NCT02111460.