Patterns of nodal metastases in palpable medullary thyroid carcinoma - Recommendations for extent of node dissection

Objective To establish the frequency, pattern and location of cervical lymp h node metastases from palpable medullary thyroid carcinoma (MTC). Recommen dations are made regarding the extent of surgery for this tumor. Summary Background Data Medullary thyroid carcinoma is a tumor of neuroendo crine origin that does not concentrate iodine. Surgical extirpation of the thyroid tumor and cervical node metastases is the only potentially curative therapeutic option. Patterns of node metastases in the neck and guidelines for the extent of dissection for palpable MTC are not well established. Methods Seventy-three patients underwent thyroidectomy for palpable MTC wit h immediate or delayed central and bilateral functional neck dissections. T he number and location of lymph node metastases in the central (levels VI a nd VII) and bilateral (levels II to V) nodal groups were noted and were cor related with the size and location of the primary thyroid tumor. Intraopera tive assessment of nodal status by palpation and inspection by the surgeon was correlated with results of histologic examination. Results Patients with unilateral intrathyroid tumors had lymph node metasta ses in 81% of central node dissections, 81% of ipsilateral functional (leve ls II to V) dissections, and 44% of contralateral functional (levels II to V) dissections. In patients with bilateral intrathyroid tumors, nodal metas tases were present in 78% of central node dissections, 71% of functional (l evels II to V) node dissections ipsilateral to the largest intrathyroid tum or, and 49% of functional (levels II to V) node dissections contralateral t o the largest thyroid tumor. The sensitivity of the surgeon's intraoperativ e assessment for nodal metastases was 64%, and the specificity was 71%. Conclusion In this series, >75% of patients with palpable MTC had associate d nodal metastases, which often were not apparent to the surgeon. Routine c entral and bilateral functional neck dissections should be considered in al l patients with palpable MTC.