Sentinel lymph node biopsy in staging of differentiated thyroid cancer: a critical review

Sentinel lymph node biopsy has recently been utilized to map tumor lymphatics in patients with differentiated thyroid carcinoma. Currently, controversy centers around the feasibility and future role of this technique in the management of differentiated thyroid cancer patients. A review of the current literature in which sentinel lymph node biopsy was performed on patients with a diagnosis of differentiated thyroid cancer was undertaken. Sentinel lymph node biopsy has been carried out on thyroid cancer patients utilizing a vital dye technique, a radiotracer technique, and a combination of both techniques. In the current literature the average rate of sentinel node identification is 91% (range 66-100%) and when identified, the sentinel node accurately predicts the disease status of the neck in most patients (range 80-100%). Limitations to carrying out the sentinel node biopsy on thyroid cancer patients include staining of parathyroid glands, identification of lymph nodes draining into the mediastinum, and the 'shine through' effect. Sentinel lymph node biopsy is technically feasible, but for a disease in which nodal metastases are of debatable prognostic value, the clinical utility of sentinel lymph node biopsy in the management of patients with differentiated thyroid cancer appears less than promising.