The effect of treatment package time on locally advanced oral cavity cancer outcomes

Objective(s): To assess the influence of treatment package time (TPT) on overall survival (OS) and event free survival (EFS) in oral cavity cancer (OCC) patients treated with surgery and adjuvant radiation therapy (RT) with or without concurrent chemotherapy (CHT). Materials/Methods: 354 adult OCC patients treated at a single, high-volume center between 2012-2022 with various pathologic risk features were included. TPT was defined as days from surgery to RT completion. KaplanMeier estimates, log-rank p-values, univariable (UVA) and multivariable (MVA) Cox regression analyses were performed to determine the impact of TPT on OS and EFS, and the optimal TPT cutoff. Results: The optimal TPT cutoff was 105 days. TPT < 105 days was significantly associated with improved OS and EFS (p = 0.002 and p = 0.027, respectively) compared to TPT >= 105 days. On UVA, factors significantly associated with OS were TPT < 105 days, former/current smoker status, pathologic stage IV, positive perineural invasion (PNI), and extranodal extension (ENE) (all p < 0.05). On MVA for OS, TPT < 105 days, former/current smoker status, pathologic stage IV, and positive PNI (all p < 0.05) remained significant. Factors significantly associated with EFS on UVA were TPT < 105 days, former/current smoker status, pathologic stage IV, positive PNI or ENE, and concurrent CHT (all p < 0.05). On MVA, TPT < 105 days, pathologic stage IV, and positive PNI (all p < 0.05) remained significant. Conclusions: In a large, homogenous cohort of OCCs, optimal TPT was <105 days, with TPT >= 105 days significantly associated with worse OS and EFS. Multidisciplinary coordination should analyze factors potentially contributing to treatment delay.