A comparison of segmental and marginal bony resection for oral squamous cell carcinoma involving the mandible.

PURPOSE: This study reviews the accuracy of preopertive diagnosis of mandibular invasion by oral squamous cell carcinoma and assesses the role of marginal resection of the mandible in its treatment. PATIENTS AND METHODS: A retrospective study of a 5-year cohort of 46 patients who underwent mandibular resection for previously untreated oral squamous cell carcinoma was done. Data evaluated included age; sex; site and stage of cancer; preoperative clinical, panoramic, and computed tomography (CT) evaluations; and histologic findings on the resection specimen. The type of mandibular resection (segmental vs marginal) and treatment outcome also were compared.
RESULTS: Clinical examination, panoramic radiographs, and CT scans were 78.5% to 82.6% accurate in diagnosing 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 involved 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 patients with local recurrence. Ten percent of patients in the segmental resection group died of oral cancer; no local recurrences were seen.
CONCLUSION: There is no completely accurate method of diagnosing bony invasion of the mandible by oral squamous cell carcinoma. A combination of 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 invasion, or with early "arrosive" invasion. It is best in the symphysis region. Careful case selection will allow a favorable oncologic outcome with preservation of the mandibular contour.