[Evaluation of the sentinel lymph node in T1-T2 papillary thyroid cancer: a preliminary study]

Sentinel lymph node biopsy in differentiated thyroid cancer may benefit patients with no clinically affected lymph nodes and can avoid a prophylactic or staging lymphadenectomy.

A prospective study was conducted on 23 consecutive patients with papillary thyroid carcinoma with no clinical or radiological suspicion of lymph involvement. After injecting methylene blue around the tumour during the biopsy of the identified sentinel lymph node, a total thyroidectomy and a via-b ipsilateral lymphadenectomy was performed for the later study with cytokeratin. If the sentinel lymph node was positive, a modified ipsilateral radical lymphadenectomy was perfumed (groups ii to v).

The sentinel lymph node was clearly identified in 21 of the 23 patients (91.3%). Seven (33%) of the 21 lymph nodes identified were positive in the intra-operative study, of which 3 (42.8%) demonstrated involvement with the lateral compartment. All together, 9 patients (39.1%) showed lymph node involvement group vi, with two more patients being identified with micro-metastases in the later study. Biopsy of the sentinel lymph node had a sensitivity of 87.5%, a specificity of 100%, a positive predictive value of 100% and a negative predictive value of 93.7%, with 7.1% false negatives. Five patients (21.7%) had transient hypocalcaemia.

The identification of the sentinel lymph node in patients with T1-T2 tumours with no suspicion of lymph node involvement helps in the selection of patients who should be treated with selective lymphadenectomies.