Rim versus sagittal mandibulectomy for the treatment of squamous cell carcinoma: two types of mandibular preservation

BACKGROUND: The role of conservative mandibulectomy for patients with bone invasion from squamous cell carcinoma remains poorly defined. However, marginal mandibular resection is biomechanically secure in its design while maintaining the mandibular continuity. This procedure has proven to be a successful method of treating squamous cell carcinoma with limited mandibular involvement. PURPOSE: The purpose of this study was to analyze our results after the use of a marginal technique for the treatment of oral and oropharyngeal cancer and to compare two types of mandibular conservative procedures: rim resection versus sagittal inner mandibulectomy. METHODS: A retrospective review of a cohort of 50 patients (global group) who underwent mandibular conservative resection for previously untreated squamous cell carcinoma was performed. Two subgroups were considered: rim group (n = 37) and sagittal group (n = 13). Clinical evaluation and preoperative radiologic studies were the means used to evaluate bony invasion and to decide on the extent of mandibulectomy. The treatment outcome after these two types of mandibular resection was calculated and compared using analysis by the Pearson chi(2) test, logistic regression model for multivariate analysis, and the Kaplan-Meier method to determine survival. RESULTS.: In the sagittal group, specimens from 2 patients (11.7%) demonstrated tumor invasion on decalcified histologic examination, whereas the rim group showed 11 cases (29.7%) with bone invasion. Local recurrence was observed in the follow-up of 10 patients. No statistical relationship was found between the presence of histologic bone invasion and the risk of local recurrence. The size of bone resection >4 cm (p =.002) and tumor invasion of surgical margins (p =.039) were found to be associated with increased local recurrence rates. In multivariate analysis, lymph node affectation significantly correlated with histologic mandibular involvement (p =.02). In the global group, the 5-year observed survival rate was 56.97%. Overall survival and rate of recurrence were comparable in both groups. In the global group, tumor infiltration beyond the surgical margin was statistically related with poor survival (p =.01). CONCLUSIONS: Analysis of this series disclosed that marginal mandibulectomy is effective in the control of squamous cell carcinomas that are close to or involving the mandible. In carefully selected patients, sagittal bone resection seems to be as appropriate as rim resection in the local control of these tumors.