Postoperative radiation therapy vs observation for pN1 oral cavity squamous cell carcinoma.

Abstract

American Society of Clinical Oncology guidelines recommend that the decision to give postoperative radiotherapy (PORT) for pN1 oral cavity squamous cell carcinoma (OCSCC) without other adverse features be based on the adequacy of the neck dissection (<18 or ≥18 nodes). We conducted a cohort study of the National Cancer Database examining how PORT affects survival. We stratified analyses by the adequacy of the neck dissection and lymph node (LN) size. Our cohort comprised 1909 patients (898 received PORT). PORT conferred a survival benefit in the overall cohort (adjusted hazard ratio 0.82, 95% CI 0.72-0.94). There was similar benefit in patients receiving inadequate and adequate neck dissections. Patients with >10 mm LN metastasis derived greater benefit compared with patients with smaller metastases. In pN1 OCSCC without other adverse features, the size of the LN metastases may predict benefit from PORT, whereas the adequacy of the neck dissection may not.