Risk factors of cancer occurrence after surgery of oral intraepithelial neoplasia: A long-term retrospective study.

OBJECTIVE: Oral intraepithelial neoplasia (OIN) is a premalignant lesion of oral mucosa graded I through III according to the importance of atypic cells and the thickness of the dysplastic layers. The aim of this study was to evaluate the long-term clinical course of OIN lesions and identify predictive factors of outcomes. METHODS: The clinical, surgical, and follow-up data of the patients consecutively treated for OIN by primary surgical removal in a referral anti-cancer center from November 1998 to March 2009 were retrospectively analyzed. The main outcome parameters were the 10-year disease-free survival (DFS), cancer-free survival (CFS), overall survival (OS), and disease-specific survival (DSS) rates (Kaplan-Meier). RESULTS: Thirty-one patients were included. Patients with positive or close margins (n = 15) had a significantly lower 10-year CFS rate (46.7% vs. 92.38%; P = .004) than patients with negative margins. This predictive factor remained significant in multivariate analysis (hazard ratio, 9.157; 95% confidence interval, 1.4-60.6). There was no significant difference in the 10-year DFS (33.3% vs. 48.7%; P = .2), DSS (92.8% vs. 100%; P = .1), and OS (92.8% vs. 69.6%; P = .2) rates between these two groups. Neither the initial OIN grade nor other clinical or surgical parameters were found to be significant predictors of outcomes. CONCLUSION: In this long-term follow-up study on histologically proven OIN treated by primary surgery, positive or close margins status was the only independent predictive factor of progression to cancer. Therefore, we warmly recommand performing re-resection rather than surveillance in cases with positive margins. Oral intraepithelial neoplasia grading or lesion size were not significant predictors of outcomes. LEVEL OF EVIDENCE: 4. Laryngoscope, 2546-2551, 2018.