Impact of different surgical margin conditions on local recurrence of oral squamous cell carcinoma.

The purpose of this study was to analyze the impact of different surgical margin conditions on local recurrence of oral squamous cell carcinoma (SCC) in 148 consecutive patients who underwent planned radical resection of oral SCC. The patients were classified into four categories according to the status of the surgical margin: clear (no SCC within 5mm, n=103), close (SCC within 5mm, n=21), dysplasia (dysplastic epithelium at margin, n=13), and involved (SCC at margin, n=11). Cox's proportional hazard model showed that the status of the surgical margin had a significant impact on local recurrence (p<0.003); hazard ratio was 3.79 (95%CI: 1.17-12.28) with a close and 7.89 (2.38-26.17) with an involved margin. The presence of mucosal dysplasia at the surgical margin was also a significant predictor of local recurrence (hazard ratio: 5.29, 95%CI: 1.31-21.29). Local recurrence was observed only with severe dysplasia, while no recurrence with mild and moderate dysplasia. In the patients with a clear and closed surgical margin, local recurrence was related with T4 tumor and an advanced mode of tumor invasion. The results of this study suggested that the presence of tumor cells at or close to the surgical margin increased the risk of local recurrence. The presence of dysplastic epithelium (especially severe dysplasia) at the mucosal surgical margin has a significant impact on local control. It was also suggested that not simply the width of the free margin but also clinical and histological risk factors should be included in deciding the necessity for adjuvant radiotherapy.