Is postoperative adjuvant therapy necessary for pT3N0 oral cavity squamous cell carcinoma?

BACKGROUND: The current NCCN guidelines advocate for the use of adjuvant radiotherapy (RT) or chemoradiotherapy (CRT) in pT3N0 oral cavity squamous cell carcinoma (OCSCC). Here, we sought to evaluate whether postoperative RT/CRT may confer a survival advantage in pT3N0 patients who lack adverse pathological features. METHODS: A dataset of 852 pT3N0 OCSCC patients treated between 2018 and 2021 was analyzed. Patients with adverse pathological features (i.e., positive margins, margins <5 mm, lymphovascular invasion, or perineural invasion) were excluded, leaving 235 eligible patients. The cohort was further refined by omitting 12 patients who received surgery plus chemotherapy and two cases who received RT doses <5000 cGy, resulting in two study groups: surgery alone (n = 131) and surgery plus RT/CRT (n = 90). RESULTS: Baseline characteristics were comparable between groups, except for a higher proportion of buccal subsite (p = 0.0063) and female patients (p = 0.0495) in the surgery alone group. Kaplan-Meier analyses revealed no significant differences in 4-year disease-specific survival (DSS) (84.2 % versus 85.9 %, p = 0.8834) or overall survival (OS) (75.6 % versus 84.8 %, p = 0.2376). These findings were confirmed by multivariable analyses and remained consistent after propensity score matching (n = 74 per group), with similar survival outcomes between groups (4-year DSS, 90.7 % versus 83.2 %, p = 0.4020; 4-year OS, 87.0 % versus 81.9 %, p = 0.6121) CONCLUSIONS: For patients with pT3N0 OCSCC lacking adverse pathological features, the addition of adjuvant RT/CRT does not appear to confer a survival benefit over surgery alone.