Feasibility of sentinel lymph node detection in nodular thyroid disease

Sentinel lymph node biopsy has been proven to be successful and accurate in predicting the nodal status in melanoma and breast cancer. Occult lymph node metastases are common in well differentiated thyroid cancer (WDTC). Although the prognostic significance of these occult lymph node metastases remains controversial, identifying these patients may help direct therapy. The purpose of the study was to assess the technical feasibility and the safety of the sentinel lymph node biopsy in uni-nodular thyroid disease.

Patients of previously untreated benign solitary thyroid nodule, diagnosed preoperatively by fine-needle aspiration cytology without any palpable cervical lymph node were prospectively studied. The nodule was injected with isosulfan blue vital dye. Blue stained lymphatics were traced. Then, hemithyroidectomy was performed.

A total of 30 patients underwent sentinel lymph node biopsy; lymphatics were observed in 23 patients and sentinel lymph nodes were found in 18. In 5 patients, blue stained lymphatics were traced to the outside of the central compartment but no sentinel lymph node was identified. Sentinel lymph nodes were located in the central compartment in 14 cases, in the lateral compartment in 3 cases and in one patient 2 sentinel lymph nodes were found in both the central and the lateral compartments. Overall detection of sentinel lymph nodes was possible in 60% of cases. There were no intra or postoperative complications.

The role of sentinel lymph node biopsy has yet to be determined in the thyroid setting. Certainly the technique can be performed safely, but its accuracy needs further refinement and investigation on larger series of patients before it can be recommended in the routine management of thyroid neoplasia.