K. Amarell1, C. Billena2, S. A. Koyfman3, J. A. Miller4, J. L. Geiger5, T. Sussman6, E. Yilmaz7, J. Ku8, N. Silver8, J. Scharpf8, B. Prendes8, D. Bottalico8, E. Lamarre8, N. M. Woody3, and S. R. Campbell4; 1Cleveland Clinic Foundation, Cleveland, OH, 2Memorial Sloan Kettering Cancer Center, Manhatten, NY, 3Department of Radiation Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, 4Cleveland Clinic, Cleveland, OH, 5Department of Hematology and Medical Oncology, Taussig Cancer Center, Cleveland Clinic, Cleveland, OH, 6Department of Hematology/Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, 7Department of Medical Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, 8Department of Otolaryngology, Head and Neck Institute, Cleveland Clinic, Cleveland, OH
Purpose/Objective(s): The optimal treatment of stage 1 single node HPV+ oropharyngeal squamous cell carcinoma (OPC) is unclear. For non-operative treatment, the benefit of concurrent chemotherapy with standard radiation (70 Gy) has not been clearly established, as evidence supporting chemotherapy is based on pre-HPV data and best for AJCC7 N2a. We sought to describe practice patterns and outcomes of stage 1 single node HPV+ OPC and compare outcomes with multi-node N1 disease. Materials/
Methods: An IRB approved database was queried for patients with AJCC 8 cT1-2N1 HPV+ OPC treated definitively from 2012-2022 with at least 2-yrs follow up. Categorial variables were evaluated with Fisher’s Exact Test. Locoregional failure (LRF) and distant metastasis (DM) rates were estimated using Cumulative Incidence and predictors were assessed with Gray’s test and competing risk regression. Disease free survival (DFS) was performed using Kaplan-Meier, and predictors were assessed with Cox proportional hazards regression. Results: Of 304 cT1-2N1 patients, 73 had single node disease (AJCC 7 N1 50.7% and N2a 49.3%). Median follow up was 4.6 years and age 60 years (42-88). Most were male (75.3%), white (90.4%) and never smokers (54.8%). All received radiation, 46 (60.0%) with concurrent chemotherapy (91.3% cisplatin), and 15 (20.5%) included oncologic surgical management. Concurrent chemotherapy was given in 51.4% and 75.0% of AJCC7 N1 and N2a patients, respectively. Median LN size in longest dimension was 2.97 cm (IQR 2.44 – 3.64). The craniocaudal (CC) dimension was most commonly largest (87.7%) and alone upstaged to AJCC 7 N2a in 34.2%. Smoking, T-stage, and cell differentiation were not associated with use of chemotherapy (p>0.05); AJCC7 N2a was associated with use of chemotherapy (p=0.023) when excluding excisional biopsy patients. LRF for single node patients was 4.1% at 2- and 5-yr, and the receipt of chemotherapy was associated with decreased LRF (0% vs 12%, p=0.02). Node volume was associated with LRF, but on multivariate analysis, use of chemotherapy only persisted (p<0.001). When comparing single versus multi node cT1-2N1 patients 5-yr LRF was 4.1% vs 2.7% (p=0.64), DM 2.7% vs 6.8% (p=0.18), and DFS 93.2% vs 90% (p=0.35). Conclusion: In this series, patients with stage 1 HPV+ OPC with single lymph node metastasis have a LRF benefit of concurrent chemotherapy, regardless of AJCC7 N1 vs N2a and smoking status. Outcomes are similar between single and multi-node patients, consistent with new grouped N1 AJCC 8 staging.
