Close margin alone does not warrant postoperative adjuvant radiotherapy in oral squamous cell carcinoma

BACKGROUND There are major variations between institutions regarding postoperative adjuvant therapy for adverse features in patients with oral squamous cell carcinoma (SCC). The authors' practice has been to not recommend any adjuvant therapy on the basis of close (<5 mm but uninvolved) margins unless there are additional adverse features. The primary objective of this study was to assess whether the local control achieved in this patient cohort was acceptable. METHODS In this single-institution, retrospective analysis, local control was the primary endpoint, and disease-specific survival (DSS) was the secondary endpoint. Differences in survival were determined using the log-rank test, and survival curves were generated using the Kaplan-Meier method. RESULTS One hundred forty-four patients (79 men and 65 women; median age, 64.1 years; mean follow-up, 3.3 years) underwent surgery alone for oral SCC with curative intent and were recorded as having close tumor margins on histology. The local control rate for all patients who underwent surgery alone was 91% (95% confidence interval, 81.9%-95.2%), and the DSS rate was 84% (95% confidence interval, 74.0%-89.9%) at 5 years. There was no pattern of worse local control or DSS rates with the ordered stratification of close margins. The 5-year local control rates for having 0, 1, 2, and 3 additional adverse features were 100%, 96%, 83%, and 71%, respectively (P =.004; trend test). CONCLUSIONS Surgery alone without postoperative adjuvant therapy offered acceptable local control in patients who had close margin status as their only adverse feature and may be reasonable in the presence of 1 other adverse clinicopathologic feature.