Abstract A28: Predictive factors for mortality after surgery alone for human papilloma virus-associated oropharynx squamous cell carcinoma: Analysis of the National Cancer Database

Abstract

Abstract Objective: Assess survival outcomes after surgery alone for p16-positive/human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (HPV+OPSCC) using the National Cancer Database (NCDB). Background: Survival outcomes for surgery alone for HPV+OPSCC without adjuvant radiation and chemotherapy are unclear. Adjuvant treatment may be unnecessary for some cases of HPV+OPSCC, given the reliance of current guidelines on extrapolations from studies of non-HPV associated OPSCC treatment. Methods: Overall survival (OS) was analyzed for 736 HPV+OPSCC patients who underwent surgery alone from 2010-2014. We studied available risk factors for death in the NCDB. Kaplan-Meir curves and crude and adjusted hazard ratios (HR) with Cox and Firth regression modeling were used. Staging was readjusted from the American Joint Committee on Cancer 7th edition to the 8th. Results: Most patients had T1/T2 (84.7%) and N0/N1 (74.7%) disease. OS after surgery alone for pathologic stage 1 disease at 3 and 5 years was 94% and 92%, respectively (p < 0.001). Stage 1 patients without adverse features (nodal involvement, lymphovascular invasion [LVI], positive margins) had equivalent survival to those with adverse features (p=0.7). Multivariate analysis controlling for pathologic T stage found the following independent risk factors for death after surgery alone: N2 versus N0 disease (HR 6.3, p=0.00002), microscopic ENE (HR 2.5, p=0.06) and macroscopic ENE (HR 4.8, p<0.02) versus LNs without ENE. Positive margins conferred increased risk of death independent of pathologic T stage (HR 2.3, p=0.003) but was nonsignificant after adjusting for pathologic N stage (HR 1.7, p=0.07). Charlson-Deyo score, T stage, N1 disease, and LVI were not significant predictors of mortality. Kaplan-Meir OS curves were significantly worse for stage 3 versus 2 versus 1 (p<0.0001), for N2 versus N1 (p<0.0001), but not for N1 versus N0 (p=0.9), for LNs without ENE versus microscopic ENE (p<0.005) versus macroscopic ENE (p<0.001), and for positive versus negative margins (p=0.002). Conclusions: In this study, limited by the lack of data on smoking history, perineural invasion (PNI), recurrence, and disease-specific survival, HPV+OPSCC after surgery alone has a high overall survival, especially when stage 1 with pathologic N0 or N1 disease without ENE. Further studies of HPV+OPSCC patients who have refused adjuvant treatment with smoking, PNI, recurrence and disease-specific survival information are needed to evaluate the utility of surgery alone, especially for stage 1 cases with N1 disease. Citation Format: Mary Han, Gaelen B. Stanford-Moore, David W. Schoppy, William R. Ryan. Predictive factors for mortality after surgery alone for human papilloma virus-associated oropharynx squamous cell carcinoma: Analysis of the National Cancer Database [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Optimizing Survival and Quality of Life through Basic, Clinical, and Translational Research; 2019 Apr 29-30; Austin, TX. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(12_Suppl_2):Abstract nr A28.