RESUMO
BACKGROUND: To evaluate margins for oral carcinoma according to types of invasion front. METHODS: Retrospective cohort of 772 patients with worst pattern of invasion (WPOI) graded 1-5. Local recurrence was the outcome of interest. RESULTS: Local recurrences occurred in 164 patients (21.2%) and was affected by WPOI type 4/5, margin distance, perineural invasion, and adjuvant radiotherapy. In patients with WPOI types 1/2/3, a cutoff of 1.7 mm was considered ideal margin extent and in patients with WPOI types 4/5, the cutoff was 7.8 mm. Patients below these thresholds had a significantly higher incidence of local recurrence. CONCLUSIONS: Different WPOI determine the ideal extent of surgical margins as 1.7 mm for patients with types 1-3, and 7.8 mm in patients with types 4/5.