Effect of adjuvant radiotherapy (RT) on overall survival (OS) for node positive head and neck squamous cell carcinoma (HNSCC)

Abstract

6087 Background: Although adjuvant RT is often recommended for locally advanced HNSCC, its effect on OS or cancer-specific survival (CSS) has not been clearly demonstrated. Methods: Within the Surveillance, Epidemiology, and End Results (SEER) Database, we selected patients with locally invasive but node negative (SEER stage 2) or node positive HNSCC (SEER stage 3–4) treated either with surgery alone (S) or surgery and radiation (S+RT). This analysis included 13,145 patients from the SEER 17 database diagnosed between 1988 and 2001. Exclusion criteria included distant metastases, no RT records or death within 3 months of surgery. The median follow-up was 4.7 years. Results: Adjuvant RT was utilized in 55% of patients with stage 2 and 84% of stage 3–4 HNSCC. For Stage 2 HNSCC, adjuvant RT was associated with lower 5 year OS on univariate analysis (46.32% for S+RT vs. 49.76% for S, p=0.016) but not on multivariate analysis (HR 1.00, p=0.93). For Stage 3 HNSCC, RT improved 5 year OS associated with RT on univariate analysis (52% for S + RT vs. 41% for S, p<0.001) and multivariate analysis (HR 0.80, p=0.002). For Stage 4 HNSCC, RT significantly improved 5 year OS on univariate analysis (35% for S + RT vs. 25% for S, p<0.001) and multivariate analysis (HR 0.75, p<0.001). The addition of RT improved 5 year CSS for both stage 3 (59.7% vs. 51.4%) and stage 4 HNSCC (42.1% vs. 32.8%). Conclusions: In the largest reported analysis of adjuvant RT in locally advanced HNSCC, adjuvant RT results in an approximately 10% absolute increase in 5-year CSS and OS for node-positive HNSCC compared to S alone. The absolute benefit of RT is underestimated on univariate analysis because patients with poor prognostic factors are more frequently selected for adjuvant RT. Outcomes in this high-risk population remain suboptimal, emphasizing the need for continued investigation of innovative treatment approaches. No significant financial relationships to disclose.