Association of patient and tumor characteristics with outcomes in young patients with head and neck squamous cell carcinoma (HNSCC)

e18054 Background: HNSCC is increasingly being diagnosed in a younger population, with a variable prognosis. While studies have evaluated outcomes in young compared to older patients, evaluation of prognostic factors specifically in younger patients, that may help guide treatment decisions, is needed. Therefore, we conducted a retrospective study to investigate the association of patient and tumor characteristics with disease specific survival (DSS) in HNSCC patients ≤45 years old (yo). Methods: Patients treated at the University of Pittsburgh Medical Center from January 1, 2007 to June 30, 2020, that were ≤45 yo at time of diagnosis with HNSCC without distant metastatic disease, were included. Those who received treatments at other institutions and who had no follow-up after index treatments were excluded. Patient demographics, social history, tumor pathology and treatment course were collected. The primary endpoint of DSS was defined as the interval between the time of pathologic diagnosis and the time of cancer-related death. Proportional hazards regression was applied separately for surgically and non-surgically treated patients. A multivariate analysis was conducted for surgically treated patients only. Results: 230 patients were included. Median age was 42, 73% male, 45% oral cavity primary, 35% oropharynx (89% Human papillomavirus positive), 14% larynx, 69% were smokers, and 73% received combined modality therapy. 35% of patients had a recurrence with the majority locoregional only (61%). Median DSS was not reached. The 5 year DSS was 73% (95% CI 67% to 80%). There was no difference in DSS between surgically treated (n = 169) and non-surgically treated (n = 61, p = 0.94) patients. For surgically treated patients, univariate analysis showed significantly worse DSS in those with higher pathologic T and N stages, positive margins, perineural invasion (PNI), extranodal extension (ENE), and negative HPV status. For non-surgically treated patients, only negative HPV status was associated with significantly worse DSS (p = 0.034). In the multivariate analysis for surgical treated patients, which included all significant characteristics from univariate analysis, pathologic T and N stage, positive margins, (HR 4.92, 95% CI 1.98-12.25, p = 0.006) and PNI (HR 2.66, 95% CI 1.17-6.08, p = 0.02) were significantly associated with worse DSS. Conclusions: Pathologic T and N stage, positive margins, and PNI are independently associated with significantly worse DSS in surgically treated HNSCC patients aged ≤45. Compared with classic prognostic factors seen in the overall population with HNSCC, PNI may be a uniquely strong prognostic factor in younger-aged HNSCC patients.