Sentinel lymph node dissection in papillary thyroid carcinoma

Background: Occult lymph node (LN) metastasis is common in papillary thyroid carcinoma. Sentinel lymph node (SLN) biopsy has been proven to be successful and accurate to predict the nodal status in melanoma and breast cancer. We investigate the use of SLN in papillary thyroid carcinoma. Methods: Patients of previously untreated papillary thyroid carcinoma, diagnosed preoperatively by fine-needle cytology without any palpable cervical LN are prospectively studied. Blue dye injection was utilized for the SLN biopsy followed by central compartment lymphadenectomy. The histopathological results of the SLN and lymphadenectomy specimens were compared. Results: Fifteen consecutive patients underwent surgery including SLN biopsy for papillary thyroid carcinoma. Occult nodal metastases were identified in 10 patients (67%). The other five cases had no nodal metastasis. SLN were found in 10 cases. One, two and three SLN were present in three, three and four patients, respectively. SLN were located in the central compartment in eight cases. The SLN were found in the lateral compartment in one case. In the remaining one case, the SLN were found in both the central and lateral compartments. Of the group with found SLN, false negative occurred in one case. The overall accuracy of the SLN in predicting the nodal status was 90%. The sensitivity, specificity, positive predictive value and negative predictive value were 88%, 100%, 100% and 67%, respectively. No complications were directly related to SLN biopsy. Conclusion: Occult nodal spread is frequently encountered in papillary thyroid carcinoma. SLN biopsy is safe and feasible in papillary thyroid cancer, however further studies are necessary to improve the diagnostic accuracy prior to routine clinical use.