Sentinel node mapping in thyroid cancer: an overview

In this paper we describe the current status of sentinel node mapping (SNM) in thyroid tumors and its potential perspectives. SNM in thyroid cancer has been tested since the end of the twentieth century, mainly in papillary thyroid cancer (PTC) and in medullary thyroid cancer (MTC). In PTC, it has been employed to find occult lymph node metastases in the central compartment of the neck as an alternative or indication for prophylactic dissection, by several methods. All of them have proven effective in spotting sentinel nodes, but the results have been somewhat diminished by uncertainty about the clinical significance of occult metastases in differentiated thyroid cancer. SNM in MTC has also been used to find occult lymph node metastases in the lateral compartments of the neck, also with excellent results hindered by a similar doubt about the real clinical significance of MTC micrometastases. Well designed, adequately sized randomized controlled trials are lacking, so SNM in thyroid tumors remains an interesting yet experimental methodology. New technology is emerging that could facilitate such studies, which could add solid information about the clinical significance of occult neck metastases in thyroid cancer.

Automated summary

This paper describes the current status and potential perspectives of sentinel node mapping (SNM) in thyroid tumors. SNM has been tested in papillary thyroid cancer (PTC) and medullary thyroid cancer (MTC) since the end of the twentieth century. While effective in spotting sentinel nodes, uncertainty about the clinical significance of occult metastases in differentiated thyroid cancer and MTC micrometastases has hindered the results. The lack of well-designed randomized controlled trials makes SNM in thyroid tumors an interesting yet experimental methodology. New technology could facilitate such studies and provide solid information about the clinical significance of occult neck metastases in thyroid cancer.