Early post-operative NI-RADS predicts recurrence and survival in high-risk oral cavity squamous cell carcinoma undergoing adjuvant radiotherapy

PurposeTo evaluate the prognostic value of the Neck Imaging Reporting and Data Systems (NI-RADS) in early post-operative imaging for predicting recurrence and survival outcomes in high-risk oral cavity squamous cell carcinoma (SCC) patients undergoing post-operative radiotherapy (PORT).MethodsThis retrospective study included 84 patients with high-risk oral cavity SCC who were scheduled for PORT after radical surgery between January 2013 and May 2024. Early imaging with contrast-enhanced CT or MRI was performed within 12 weeks post-surgery and scored using the NI-RADS system. Associations between NI-RADS scores, recurrence, and survival outcomes were analyzed using Kaplan-Meier and Cox proportional hazards models.ResultsAlthough NI-RADS was originally designed for post-treatment surveillance, we applied it to early post-operative imaging as an exploratory risk-stratification tool. NI-RADS scores significantly predicted regional disease-free survival (DFS) and overall survival (OS). Patients with higher NI-RADS T and N scores had poorer outcomes. Multivariable analysis confirmed early NI-RADS T as an independent predictor of OS (p = 0.01). Interobserver agreement for NI-RADS classifications was strong (Weighted Kappa: T = 0.837, N = 0.855). Although higher radiotherapy doses were administered to patients with NI-RADS 2-3 scores, these patients demonstrated worse outcomes, reflecting aggressive disease.ConclusionEarly application of NI-RADS in post-operative imaging provides valuable prognostic insights, enabling risk stratification and tailored management in high-risk oral cavity SCC patients. Streamlining imaging workflows and exploring alternative therapeutic strategies for high-risk groups may further optimize outcomes.