Postoperative radiotherapy for early oral squamous cell carcinoma with a single ipsilateral lymph node metastasis — a retrospective cohort study

Background/aims Managing early oral squamous cell carcinoma (OSCC) with a solitary ipsilateral lymph node metastasis (pN1) and no additional adverse features remains controversial, with conflicting international guidelines. Our study examined the effect of postoperative radiotherapy (PORT) compared with surgery only (SO) on several survival outcomes in a clinical cohort. Methods Patients diagnosed with a primary pT1–2 OSCC and a single ipsilateral lymph node metastasis (pN1) without an extranodal extension were retrospectively identified. Factors associated with receiving PORT were assessed using logistic regression. Adjusted Cox regression models were used to examine the association between PORT and overall survival (OS) and regional recurrence-free survival (R-RFS) in the whole cohort and in different subgroups. Results In total, 85 patients were included in our study, of whom 43 received PORT. Three factors were predictors of receiving PORT in our cohort, namely: poor differentiation, high-risk margins, and bilateral neck dissection. Overall survival and probability of regional recurrence after 60 months were comparable between groups: 63% and 30% in the SO group and 65% and 25% in the PORT group, respectively. After adjusting for established confounders, PORT was not associated with improved OS HR (PORT vs SO = 0.94; 95% CI 0.46–1.92; p = 0.9) nor with improved regional recurrence-free survival (PORT vs SO = 0.81; 95% CI 0.30–2.17; p = 0.7. Subgroup analyses revealed potential benefit from PORT in patients with pT2 tumors, age under 70 years, and inadequate neck dissection (lymph node yield < 18 nodes). Conclusion While registry-based studies often lack granular data on comorbidities and specific recurrence types, our results suggest that the marginal gains of PORT may not justify its high morbidity, including significant long-term impacts on quality of life. Observation seems to be a safe alternative to routine irradiation in carefully selected pT1–2 pN1 OSCC cases, provided surgical neck management is adequate.