SA1 - Is Timing of Adjuvant Therapy Associated With Disease Recurrence in Oral Cavity Squamous Cell Carcinoma?

Abstract: Survival rates with oral squamous cell carcinoma (OSCC) have been stagnant for decades. Some OSCC patients receive delayed adjuvant therapy (AT) outside of the recommended 6-week postoperative window. Therefore, timing of AT is a potentially modifiable risk factor that may improve disease control and survival. The study's purpose was to determine if adjuvant therapy delivered within 6 weeks of surgery was associated with a reduced risk of OSCC recurrence. This retrospective cohort study included patients with OSCC treated with curative-intent surgery and radiation, with or without chemotherapy, at the Department of Oral and Maxillofacial Surgery, University of Washington, from January 2009 to January 2025. The primary predictor was the timing of AT initiation, categorized as =6 weeks or 6-12 weeks following surgery. The primary outcome was disease recurrence, and the secondary outcome was early recurrence within one year of completing adjuvant therapy. Covariates included demographic factors, social habits, surgical treatment variables, and disease characteristics. Data were abstracted uniformly from the electronic medical record by a single research investigator. Bivariate analyses compared clinical, demographic, and pathological variables between adjuvant therapy timing groups and assessed associations between study predictors and outcomes, including disease recurrence and early recurrence. Chi-square tests were used for categorical variables and independent t-tests for continuous variables. Variables significantly associated with outcomes were included in multivariable logistic regression models. Statistical significance was defined as P < .05. The sample was composed of 78 subjects with an average age of 60.1 years (SD = 10.7). Only 19 (24.4%) of subjects received AT within 6 weeks of surgery. Disease recurrence occurred in 40 (51.3%) subjects during the study period. There was no significant association between AT with a 6-week cut off and disease recurrence (P = .69). Those who had a recurrence did not have a significantly longer time to AT (8.4 vs 7.4 weeks, P = .06). The subset of subjects who experienced early recurrence (n = 27, 34.6%) likewise did not have higher rates of AT delays >6 weeks (P = .81). Early recurrence was also not associated with longer time to AT (8.3 vs 7.7 weeks, P = .24). Overall recurrence occurred in 51.3% of patients and was significantly associated with adverse pathologic features (greater nodal burden, increased depth of invasion, lymphovascular and perineural invasion) and intensified treatment (free flap reconstruction, longer hospital stays, concurrent chemotherapy). In conclusion, there was no association between AT timing and either overall or early disease recurrence. Punctual coordination of AT is important; however, other disease-specific factors may have a stronger influence on disease control.



References:

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2. Mrosk F, Absah M, Richter M, Sprunken E, Doll C, Kreutzer K, et al. The impact of time between surgery and adjuvant chemoradiotherapy in advanced oral cavity squamous cell carcinoma. Front Oncol. 2024;14:1393910. doi:10.3389/fonc.2024.1393910.