Radiation therapy treatment facility and overall survival in the adjuvant setting for locally advanced head and neck squamous cell carcinoma.

ABSTRACT

BACKGROUND: Treatment at high-volume surgical facilities (HVSFs) provides a survival benefit for patients with head and neck squamous cell carcinomas (HNSCCs); however, it is unknown what role postoperative radiation therapy (PORT) plays in achieving the improved outcomes. METHODS: From the National Cancer Database, 6844 patients with locally advanced invasive HNSCCs of the oral cavity, oropharynx, larynx, and hypopharynx who underwent definitive surgery with PORT between 2004 and 2013 were identified. HVSFs were those in the top percentile for annual case volume during this period. RESULTS: The median follow-up was 54 months. Compared with a lower volume surgical facility (LVSF), an HVSF improved 5-year overall survival (OS; 57.7% at HVSFs vs 52.5% at LVSFs; P = .0003). Overall, 31.6% of the patients changed their radiation therapy (RT) facility after surgery, with this being more common at HVSFs (39.1% vs 28.9% at LVSFs; P < .001). Among those patients undergoing surgery at an HVSF, remaining at the same facility for RT improved 5-year OS (63.1% vs 49.3% with a facility change; P < .0001). A propensity score-matched cohort of patients treated at HVSFs confirmed the improved 5-year OS when patients remained at the treating HVSF for RT (59.2% vs 50.7% with a facility change; P = .005). In a multivariate analysis, treatment at an HVSF and remaining there for RT resulted in a reduced hazard of death (hazard ratio, 0.81; 95% confidence interval, 0.69-0.94; P = .006). CONCLUSIONS: The survival benefit associated with HVSFs persists only when patients remain at the facility for RT, and this suggests that facility specialization and/or high-volume PORT may assist in driving the OS improvement.