A COMPARISON OF SEGMENTAL AND MARGINAL BONY RESECTION FOR ORAL SQUAMOUS-CELL CARCINOMA INVOLVING THE MANDIBLE

Purpose: This study reviews the accuracy of preoperative diagnosis of mandibular invasion by oral squamous cell carcinoma and assesses the r ole of marginal resection of the mandible in its treatment. Patients a nd Methods: A retrospective study of a 5-year cohort of 46 patients wh o underwent mandibular resection for previously untreated oral squamou s cell carcinoma was done. Data evaluated included age; sex; site and stage of cancer; preoperative clinical, panoramic, and computed tomogr aphy (CT) evaluations; and histologic findings on the resection specim en. The type of mandibular resection (segmental vs marginal) and treat ment outcome also were compared. Results: Clinical examination, panora mic radiographs, and CT scans were 78.5% to 82.6% accurate in diagnosi ng mandibular invasion by squamous carcinoma. Clinical examination and panoramic radiographs are more sensitive than CT scans (86.6% vs 53%) , but CT scans were more specific (92.5% vs 80%). The mandible was inv olved in 65% of patients with segmental resection and 7.6% of patients who had a marginal resection. Nineteen percent of the patients in the marginal resection group died of their oral cancer, two of five patie nts with local recurrence. Ten percent of patients in the segmental re section group died of oral cancer; no local recurrences were seen. Con clusion: There is no completely accurate method of diagnosing bony inv asion of the mandible by oral squamous cell carcinoma. A combination o f clinical examination, plain radiographs, and computed tomography (CT ) scans may improve the diagnosis. Marginal resection is best reserved for cancers close to the bone with no invasion, minimal cortical inva sion, or with early ''arrosive'' invasion. It is best in the symphysis region. Careful case selection will allow a favorable oncologic outco me with preservation of the mandibular contour.