Use of preoperative lymphoscintigraphy and intraoperative gamma-probe detection for identification of the sentinel lymph node in patients with papillary thyroid carcinoma

Aims Lymph node metastases for papillary thyroid carcinoma are associated with an increased incidence of locoregional recurrence. The use of preoperative lymphoscintigraphy and intraoperative gamma probe detection to localize the sentinel lymph node in papillary thyroid carcinoma was investigated. Methods From February 2004 to December 2005 the sentinel lymph node technique was studied in 64 consecutive patients with cytological evidence of papillary thyroid carcinoma. The day before surgery, patients were submitted to US-guided peri-tumoural injection of the radiotracer and a lymphoscintigraphy was performed. In the operating room a total thyroidectomy was done, and thanks to a hand-held gamma probe the sentinel lymph node and all lymph nodes, belonging to the sentinel node compartment, were removed. Results The gamma probe identified the sentinel lymph node in 62 patients (96.8%). We found 48 (77.5%) sentinel lymph node without metastases; 12 (19.3%) with metastases and 2 (3.2%) with micrometastases. In 7 cases (11.3%), with a negative sentinel lymph node, metastases in other nodes of the same region were recorded. In 22 cases (34.3%) the ultrasound give an erroneous indication (P = 0.004). Five patients (8.0%), 4 with multifocal cancer, had a positive postoperative lymphoscintigraphy. Conclusion This study shows that the sentinel lymph node technique for papillary thyroid carcinoma is feasible, repeatable, and more accurate than preoperative ultrasound. In cases of multifocal thyroid lesions more patients should be enrolled to establish the utility of the radio-guided technique.