Patterns of nodal involvement for clinically N0 salivary gland carcinoma: refining the role of elective neck irradiation.

BACKGROUND The purpose of this study was to analyze the pattern of occult cervical lymph node metastasis among patients with clinically N0 salivary gland carcinoma. METHODS One hundred nineteen patients underwent primary surgery and ipsilateral neck dissection for clinically N0 carcinomas of the major and minor salivary glands. Eighty patients (67%) had parotid tumors. Distribution of T classification was: T1 (18%), T2 (28%), T3 (23%), and T4 (32%). RESULTS Twenty-five patients (21%) had pathological cervical disease. The incidence was highest among patients with adenocarcinoma (35%) and high-grade mucoepidermoid carcinoma (35%). The most common site of cervical lymph node metastasis was level II (71%), followed by level III (15%), and level IB (8%). On multivariate analysis, histological subtype was independently predictive of occult pathological lymph node metastasis (p < .001). CONCLUSION The likelihood of occult cervical lymph node metastasis for patients with salivary gland carcinoma is driven predominantly by histological subtype. Implications for elective neck irradiation are discussed.