Detection of sentinel lymph nodes in patients with papillary thyroid cancer

OBJECTIVES: To determine the feasibility of sentinel lymph node biopsy as a means of evaluating the cervical lymph nodes of patients with papillary thyroid cancer. METHODS: Isosulfan blue dye was injected around the tumour of 68 patients with papillary thyroid cancer; sentinel lymph node biopsy was performed in addition to subtotal thyroidectomy and central and modified lateral neck lymph node dissections. Surgical specimens were examined by routine processing to determine whether metastasis was present. RESULTS: Sentinel lymph nodes were identified in 63 (92.6%) of the 68 patients. There was concordance between the sentinel lymph node status and the final regional lymph node status in 58 (92.1%) of the 63 patients. There were five false-negative cases. Sentinel lymph node biopsy had a sensitivity of 87.5% (35/40), specificity of 100% (23/23), positive predictive value of 100% (30/35), negative predictive value of 82.1% (23/28), and accuracy of 92.1% (58/63). CONCLUSIONS: Sentinel lymph node biopsy may allow discrimination between patients with true lymph-node-negative papillary thyroid carcinoma and those with non-palpable metastatic lymph nodes. It may also be helpful in diagnosing metastases and avoiding unnecessary lymph node dissection in thyroid cancer.