Addition of Definitive Radiotherapy to Chemotherapy in Patients With Newly Diagnosed Metastatic Nasopharyngeal Cancer.

Management of metastatic (M1) nasopharyngeal cancer (NPC) is controversial; data suggest high overall survival (OS) rates with definitive chemoradiotherapy (CRT). Herein, we evaluated OS in patients with M1 NPC undergoing chemotherapy alone versus CRT. The National Cancer Data Base was queried for M1 NPC cases. Patients undergoing no/unknown chemotherapy and/or with unknown/nondefinitive radiotherapy (RT) doses (<60 Gy) were excluded. Logistic regression analysis ascertained clinical factors associated with RT administration. Kaplan-Meier analysis evaluated OS between both cohorts; Cox proportional hazards modeling assessed factors associated with OS. Survival was then evaluated between matched populations using inverse-probability-weighted regression adjustment. OS between groups was also measured in patients surviving ≥1 and ≥3 years to address bias from poor-prognostic subsets (eg, widely disseminated disease), and those receiving CRT ≤30 and ≤60 days of each other (surrogates for concurrent CRT) versus >30 and >60 days (sequential) of each other. Of 555 patients, 296 (53%) received chemotherapy alone and 259 (47%) underwent CRT. Patients undergoing CRT more often had private insurance (=.001) and lived in areas with higher education levels (=.028). Median OS in the chemotherapy-only and CRT cohorts were 13.7 and 25.8 months, respectively (<.001); differences persisted between matched populations (<.001). On multivariate analysis, receipt of additional RT independently predicted for improved OS (<.001). OS differences between cohorts remained apparent when evaluating patients surviving for ≥1 (<.001) and ≥3 (=.002) years. Patients who received concurrent or sequential CRT displayed improved OS over those receiving chemotherapy alone, for both the 30-day (<.001) and 60-day cutoffs (<.001). Patients with M1 NPC undergoing definitive RT and chemotherapy experienced higher survival than those receiving chemotherapy alone. Risk stratification and patient selection for such combined modality interventions is critical.