Outcomes of patients with oral cavity squamous cell carcinomas with perineural invasion treated with adjuvant intensity modulated radiation therapy (IMRT)

AbstractBackground Oral cavity cancers are among the most common malignancies worldwide with increasing incidence and mortality. In patients with high-risk prognostic features, adjuvant radiation with concurrent chemotherapy improves survival. The local recurrence and survival benefit from adjuvant radiation therapy is poorly understood in patients with intermediate risk factors including perineural invasion (PNI). Methods We performed a single institution retrospective review of 494 patients with oral cavity squamous cell carcinoma (OCSCC) treated with adjuvant intensity modulated radiation therapy (IMRT). Eligible patients included those with OCSCC who underwent surgical resection between July 2002 and August 2021 treated with adjuvant IMRT with or without chemotherapy. Survival outcomes were measured by Kaplan-Meier methodology. Results The presence of PNI or extranodal extension (ENE) correlated with significantly worse 3-year locoregional recurrence-free survival (LRFS), distant metastasis-free survival (DMFS), relapse-free survival (RFS), and overall survival OS in patients with OCSCC treated with surgical resection and adjuvant IMRT. Lower T category or N category as well as treatment package time less than 6 weeks correlated with significantly improved LRFS, DMFS, RFS, and OS. Conclusions PNI is an intermediate risk factor found to be a significant negative independent prognostic indicator in our patient cohort, which can help guide clinical decision-making for patients with OCSSC.