Role of sentinel node in differentiated thyroid cancer: a prospective study comparing patent blue injection technique, lymphoscintigraphy and the combined technique

Purpose The purpose of the present study was to evaluate the feasibility and reproducibility of the sentinel lymphnode (SLNs) biopsy in differentiated thyroid cancer using patent blue injection, lymphoscintigraphy and the combined techniques.
Methods Between January 2011 and January 2013, 82 consecutive patients were enrolled in our prospective multicentre study. Inclusion criteria were 18 years of age, preoperative diagnosis of differentiated thyroid carcinoma, no evidence of lymph node enlargement and multifocal neoplasm. To investigate the benefits of each procedure, all patients underwent total thyroidectomy plus central compartment lymphadenectomy, and in all cases, the SLN was identified via one of three techniques using the same protocol. Results Lymphoscintigraphy was used in five patients, patent blue injection was used in 40 patients, and a combined technique was used in 40 patients to identify sentinel lymphnodes (SLN). SLNs were identified in 61 cases. In the patent blue injection technique, the sensitivity, specificity and false negative rates were 88.9, 94.4 and 3.8%, respectively. In the lymphoscintigraphy technique, the percentages of sensitivity and specificity were 100%, and the percentage false negative was 0%. For the combined techniques, the corresponding values were, respectively, 69.2, 90, and 17.4%. Metastases were detected in nine cases of lateral-cervical nodes, ipsilateral tumour metastases were observed in eight cases, and
contralateral tumour metastasis was observed in one case. Conclusion Additional well-designed randomized studies are needed to validate and further optimize the SLN biopsy in patients with differentiated thyroid cancer.