Tumor above the spinal accessory nerve in papillary thyroid cancer that involves lateral neck nodes: a common occurrence.

OBJECTIVE To describe the nature and extent of lateral neck node metastases from papillary thyroid cancer in relation to presenting physical examination and staging radiologic studies. DESIGN Retrospective study. SETTING Tertiary referral cancer center. PATIENTS Consecutive patients who underwent comprehensive neck dissection with or without concurrent thyroidectomy for well-differentiated thyroid cancer between 1991 and 2001. Excluded were patients with well-differentiated thyroid cancer diagnosed incidentally at the time of treatment of other primary head and neck cancer, those with previous neck dissection for nonthyroid malignancies, and those undergoing surgery for medullary thyroid cancer. INTERVENTIONS All pathology and operative and preoperative radiology reports for patients undergoing comprehensive neck dissection for well-differentiated thyroid malignancy were reviewed. Data were collected on previous procedures, preoperative evaluation, operative details, and pathologic findings. MAIN OUTCOME MEASURE Identification of metastatic thyroid cancer in one or more nodes in anatomically defined drainage basins of the central and lateral neck. RESULTS A total of 51 neck dissections were performed. All patients had preoperative evidence of metastatic disease. In addition to the usual comprehensive node dissection encompassing all lymphatic tissue in levels II through V, level I nodes and level II nodes above the spinal accessory nerve were labeled as distinct regions in 16 (31%) and 34 (67%) specimens, respectively. Disease was confined to a single nodal level in 20 (39%) of 51 specimens and was present in 4 or more levels in 7 (14%) of 50 neck dissections. There was cancer at 2 or 3 levels in 16 (31%) and 15 (29%) cases, respectively. Seven (21%) of the 34 patients undergoing separate analysis of nodes from above the spinal accessory nerve had cancer there. In 3 of the 34 it was the sole disease in level II. CONCLUSIONS Tumor involvement at multiple nodal levels occurs in most cases when patients have lateral cervical node metastases. "Skip" metastases and cancer above the spinal accessory nerve are common. Neck dissections should include all node stations likely to be involved because selective node excision is likely to leave metastatic disease in situ.