Effectiveness of Resective Surgery in Complex Ameloblastoma of the Jaws: A Retrospective Multicenter Observational Study

SIMPLE SUMMARY: Ameloblastomas are rare, benign, progressively growing epithelial odontogenic tumors with a high tendency to relapse. Although numerous studies concerning the treatment of these tumors have been published, there is still no unanimity. This study seeks to confirm whether radical surgery is more effective in avoiding relapses. We included 55 patients affected by complex ameloblastoma, characterized by recurrence, soft-tissue involvement, erosion of internal/external cortical walls with involvement of the inferior margin of the mandible, and/or invasion of the maxillary sinus or nasal cavity. All patients underwent wide surgical resection and were then followed for an average of 108 months, with a recurrence rate of 10.9%. Maxillary ameloblastoma has an increased risk of recurrence, especially in patients who underwent previous surgical treatments. Our results suggest that complete resection could prevent the onset of relapse. However, this treatment seemed less effective in preventing recurrences in the soft tissues or maxillary sinus. ABSTRACT: Ameloblastoma is a rare, benign, odontogenic tumor of epithelial origin, characterized by locally aggressive, expansive growth. Treatment is controversial due to the risk of relapse. The aim of this multicenter retrospective study was to evaluate the effectiveness of complete resection in cases of complex ameloblastoma, which is considered at a higher risk of recurrence. Patients who met at least one of these criteria were included: recurrence, soft-tissue involvement, complete erosion of internal/external cortical walls with involvement of the inferior margin of the mandible, and invasion of the maxillary sinus or nasal cavity. Demographic data, tumor site, type of surgery, histological features, and follow-up information were collected for each patient. The cohort included 55 patients with a mean follow-up of 108 ± 66 months. A multivariate logistic model was used to evaluate variables independently associated with relapse. There were six soft-tissue or maxillary sinus relapses, with a recurrence rate of 10.9%. Most of them arose in patients previously treated. The statistical analysis identified the maxillary location as a fundamental relapse risk factor. En bloc resection with large surgical safety margins seemed to be effective in preventing the relapses. However, complete resection was less effective in preventing recurrences in the soft tissues or maxillary sinus.