Risk factors for local recurrence following marginal mandibulectomy in gingival cancer.

Surgery is the first line of treatment in gingival cancers of the mandible, and bone resection is necessary in the majority of cases. In the less extensive surgical option, marginal mandibulectomy (MM), the mandibular base is preserved. In contrast, in a segmental mandibulectomy (SM) the mandible is divided and the continuity is not preserved. If MM can be performed with comparable oncological results to SM, it is the preferred method. The aim of the present study was to identify preoperative predictors for local recurrence (LR), to support the selection of candidates for MM. Outcome measures were local recurrence free survival (LRFS) and disease specific survival (DSS). 67 patients treated with MM between 2008 and 2021 were included. Cox regression analyses of LR with hazard ratios and adjustments for postoperative radiotherapy, pathological T-stage (pT) and soft tissue margins were performed. 5-years LRFS was 63% (95% CI 46.9-75.5) and DSS 80.6% (95% CI 64.7-89.9). In conclusion we found that edentulous patients, more advanced pT-stage and positive soft tissue margins had increased risk for LR. Future studies of the correlation between cT and pT would be important to provide more robust preoperative support in the selection between MM and SM.