Computed tomography and lymphoscintigraphy to identify lymph node metastases and lymphatic drainage pathways in oral and oropharyngeal squamous cell carcinomas

Abstract.

Clinical examination alone is not enough to establish the true extent of local involvement and regional metastases. It has been suggested that computed tomography (CT) may provide valuable information for pretreatment staging. The role of lymphoscintigraphic analysis has not been investigated extensively in oral and oropharyngeal carcinoma. Information about the age, gender, site, size of the tumor, lymph node status and the tomographic and lymphoscintigraphic data were analyzed in 48 patients diagnosed with oral and oropharyngeal squamous cell carcinoma. The sensitivity of the homolateral clinical examination and CT were 77% and 55%, respectively, and the contralateral results were 66% and 16%, respectively. The specificity of the homolateral exams was 71% and 76% for the clinical examination and CT, respectively, whereas that of the contralateral exams was 100% and 90%, respectively. Lymphoscintigraphy showed the drainage pathway of the ^99m Tc-Dextran 500 in 64.6% of the cases. Homolateral drainage was favored by the tumors staged T1 and T2 that were clinically negative for nodal metastases. Bilateral drainage was associated with tumors close to or involving the midline. Non-drainage was related to tumors larger than 3.5 cm, stages T3 and T4, and the clinical presence of cervical metastases. Clinical examination was more efficient than CT to identify lymph node metastases. Lymphatic drainage of the head and neck regions is complex, and lymphoscintigraphy can be useful in oral and oropharyngeal carcinomas in clinical stages I and II, but further studies are necessary to standardize the methodology.