SENTINEL LYMPHADENECTOMY IN THYROID MALIGNANT NEOPLASMS

Background: Lymphnode metastases for well-differentiated thyroid cance r are associated with high recurrence rates. Surgical options consist of blind nodal sampling, ''berry-picking'' procedures, and modified ra dical neck dissections. Sentinel lymph node dissection (SLND) has been described by our institution for melanoma and breast cancer. We have investigated the feasibility of SLND for thyroid cancer. Design: From August 1994 to October 1996 we investigated the technique of intraoper ative lymphatic mapping and SLND in 17 patients undergoing surgical ma nagement of a suspicious thyroid nodule not accompanied by palpable ce rvical adenopathy. Setting: Patients were referred from endocrinologis ts in community and academic practices. Procedures were performed in a community hospital. Patients: There were 14 women and 3 men, ranging in age from 22 to 69 years (median, 48 years). Interventions: At surge ry, we exposed the thyroid lobe and used a tuberculin syringe to injec t 0.1 to 0.8 mt of 1.0% isosulfan blue dye (mean, 0.5 mt) directly int o the thyroid mass. Within seconds the blue dye passed along the lymph atics to the sentinel lymph node, which was then excised. Nodes were e xamined by routine processing and keratin immunohistochemical analysis to detect micrometastasis. Main Outcome Measures: The feasibility of lymphatic mapping in determining primary drainage of suspicious thyroi d nodules. Results: Lymphatic mapping and SLND was followed by total t hyroidectomy, except in 1 patient who underwent lobectomy for benign d isease. Of the 17 nodules, 12 were ultimately diagnosed as thyroid car cinoma, 3 were follicular adenomas, and 2 were colloid nodules. Tumor sizes ranged from 0.8 to 4.0 cm. Lymphatic mapping was unsuccessful in 2 patients, whose lymphatics mapped to the retrosternum. All of the s entinel lymph nodes were paratracheal except in 2 women who also had j ugular nodes that stained blue. Five (42%) of the 12 tumor nodules wer e associated with positive sentinel lymph nodes. Central neck dissecti ons were performed in 5 patients; in 2 instances (17%), the sentinel n ode was the only tumor-bearing lymph node. Conclusions: This is the fi rst report of SLND for thyroid carcinoma. Our preliminary findings ind icate that SLND can detect nonpalpable nodal metastasis with the same ease as in melanoma and breast cancer. The clinical significance of th is technique in thyroid cancer remains to be determined.