Predictors of mandibular involvement in cancers of the oromandibular region.

PURPOSE: Invasion of the mandible by oral squamous carcinoma is not only a relative contraindication to mandible conservation but also an indicator of poor prognosis. This study looks at clinical, radiologic, and operative variables that may help in predicting mandibular bone involvement. PATIENTS AND METHODS: A prospective study was carried out to evaluate the mandibular involvement and its predictors in 51 cases of oral squamous carcinoma located in the mandibular region. All patients underwent segmental- or hemimandibulectomy. A detailed clinical examination was followed by radiologic assessment and operative assessment. Statistic analysis was carried out by chi(2) test (odds ratio [OR] with a significance level of 5%). Multivariate analysis was carried out by logistic regression analysis. RESULTS: Univariate analysis identified location of tumor on lower alveolus (OR = 8.5), sensory disturbances of inferior alveolar nerve (OR = 16.2), location of tumor within 1 cm of mandible (OR = 1.4), presence of findings on periosteal striping (OR = 2.0) like subperiosteal reaction (OR = 3.5), cortical expansion (OR = 8.8) and presence of pathologic fracture (OR = 2.3) as predictor of bone invasion. Grade of tumor (P = .05) and radiologic bone involvement (P = .02) were found to be significant independent predictors of pathologic bone involvement on multivariate analysis. CONCLUSIONS: It is possible to identify mandibular invasion in almost all cases of oral squamous carcinoma by combining clinical examination, radiologic findings, and findings on periosteal stripping. This helps surgeons to make an informed preoperative and intraoperative decision about mandibular conservation. However, one should be careful when evaluating bone involvement on periosteal stripping as this cannot be recommended as a method of choice due to fear of tumor dissemination and violation of oncologic principles.

Patterns of mandibular invasion in oral squamous cell carcinoma of the mandibular region.

BACKGROUND: Mandibular resections are routinely carried out for achieving a R0 resection for oral cancers. However, the need of mandibular resection to achieve this has always been questioned. The present study was carried out to define the pattern of mandibular involvement in carcinoma of the mandibular region. PATIENTS AND METHODS: A total of 25 consecutive patients who had undergone mandibular resection and were found to have mandibular invasion were studied in a prospective open fashion. After decalcification the specimens were serially sectioned at 1 cm interval to identify invasion of mandibular bone. Type of invasion, route of spread and host cell reactions were also recorded. RESULTS: The mandibular involvement was infiltrative in 14(56%) and erosive in 11(44%). It was cortical in 5(20%), marrow involvement was seen in 15(60%) while 5(20%) had spread through the inferior alveolar canal. Of the 25, 24(96%) lesions were located with in 1 cm of the mandible. CONCLUSION: The possibility of mandibular involvement is higher in patients where tumours are located with in 1 cm of the mandible. Involvement of mandible through the canal of inferior alveolar nerve in the present study was relatively high (20%). Therefore it is recommended that before a decision is taken to preserve the mandible it should be thoroughly screened for possible involvement.