Demographic and Clinicopathological Factors Associated With Delayed Postoperative Radiotherapy in Patients With Resected Oral Cavity Cancer

Background Delayed postoperative radiation therapy (PORT) is associated with adverse outcomes in oral cavity cancer (OCC). We identified factors associated with PORT delay in a large integrated health system. Methods This retrospective study included patients aged 18–95 years who underwent OCC resection followed by PORT at Kaiser Permanente Southern California from 2015 to 2025. Univariate analyses and random forest regression evaluated predictors of PORT timing. Results Among 252 patients, 225 (89.3%) initiated PORT later than 6 weeks after surgery. Median time to PORT was 8.57 weeks (interquartile range, 2.86). Random forest modeling identified postoperative length of stay (LOS), margin status, concurrent systemic therapy, and readmission within 60 days as the variables contributing most to prediction of PORT timing. Univariate analysis identified postoperative LOS as the only significant predictor. Conclusion Earlier multidisciplinary coordination may improve PORT timeliness in integrated health systems.