Is it necessary to receive radiation for pT3-4N0 oral cancer without other adverse risk features?

OBJECTIVE: The purpose of this study was to explore the necessity of adjuvant radiotherapy for well-differentiated pT3-4aN0M0 OSCC without other negative features histologically. PATIENTS AND METHODS: This is a double-center, ambispective cohort study enrolling 250 patients with well-differentiated pT3-4aN0M0 OSCC. RESULTS: 250 patients were enrolled in the double-center study, 155(62.0%) men and 95 (38.0%) women, and the mean age was 60.1 +/- 11.1 years. T staging was classified as follows: T3 (n=99, 39.6%), and T4a (n=151, 60.4%). Kaplan-Meier analysis showed that there was no significant difference in the DSS between patients who received adjuvant radiotherapy (72.2%) and those who did not (77.4%) (p=0.615). Specifically, no significant difference was found in the DSS of pT3N0M0 or pT4aN0M0 patients who received adjuvant radiotherapy compared with those who did not (pT3N0M0: 71.9% vs. 75.8%, p=0.993; pT4aN0M0: 72.4% vs. 78.5%, p=0.491). The Cox proportional hazards regression models showed that no factor was independent prognostic factor for pT3-4aN0M0 patients, or pT3N0M0 subgroup or pT4aN0M0 subgroup in DSS. And no independent prognostic factor was found for the surgery alone subgroup and adjuvant radiotherapy subgroup. CONCLUSIONS: The results showed that adjuvant radiotherapy did not obviously improve the prognosis of pT3-4aN0M0 well-differentiated OSCC without other negative features.