Use of surgical gamma probe for the detection of lymph node metastases in differentiated thyroid cancer

Background: patients with differentiated thyroid cancer (DTC) after total or near-total thyroidectomy require I-131 therapy. After surgery the persistence of lymph node metastases in our series of patients was frequent (30%). Such patients are preferentially treated with radioiodine and shifted to surgical reintervention when the nodal lesions persist after two I-131 treatments. Aim: Use of an intraoperative radioactive probe (C-TraK) to allow a more radical surgical approach in thyroid cancer patients submitted to surgery for lymph node metastases, Methods and results: After adequate withdrawal of L-thyroxine suppressive therapy six patients were given high I-131 doses followed by post-therapy WBS which demonstrated cervical activity in 5 patients and peri-jugular activity in 1. Surgery with the help of a gamma probe allowed to detect and remove all metastatic nodes. After excision all surgical specimens showed higher radioactive counts with respect to the background. The post-surgical scan showed the disappearance of all areas of I-131 uptake. Histology confirmed the presence of metastatic lesions from papillary thyroid cancer. Conclusions: We conclude that the use of a gamma probe can be successful in patients with metastatic neck lesions resistant to I-131 treatment, particularly in patients with nonpalpable lesions.