Prognostic value of mandibular involvement in oral cavity cancers.

OBJECTIVES

The aim of the study was to determine, in a homogeneous population, the prognostic impact of mandibular involvement in oral cancers.

STUDY DESIGN

Retrospective study of 117 patients with T4 squamous cell carcinoma of the oral cavity treated by surgery and radiotherapy in the ENT Department of Bichat-Claude Bernard Hospital. All patients had histologically confirmed mandibular involvement. Patients with partial involvement of the mandible underwent rim mandibulectomy (RM) and those with extensive invasion underwent segmental mandibulectomy (SM).

METHODS

The local failure rate and the overall survival curves were calculated with respect to type of mandibulectomy. The causes of death were analysed.

RESULTS

The surgery was conservative in 55 cases (47%) and segmental in 62 patients (53%). The degree of mandibular involvement did not influence the local failure rate (29% and 25% in the RM and SM groups, respectively). On the other hand, it strongly influenced vital outcome, as five-year survival was only 25.4% after segmental mandibulectomy, compared to 40% after rim mandibulectomy. The metastases and the second primary tumors were more frequent in the SM group.

CONCLUSION

The degree of mandibular invasion influenced the survival rate of patients with squamous cell carcinoma of the oral cavity but this difference is not due to local failure.