Sentinel lymph node biopsy in thyroid cancer: it can work but there are pitfalls.

OBJECTIVE

The aim of this study is to retrospectively assess the specific perils associated with conducting sentinel lymph node biopsies to determine whether a central compartment neck dissection (CCND) is necessary in well-differentiated thyroid cancer. The goal was to assess the specific reasons for a false negative in 3 specific patients among a large population of thyroidectomy patients.

STUDY DESIGN

Case series with chart review.

SETTING

Three McGill University teaching hospitals that are part of the McGill University Thyroid Cancer Center in Montreal, Quebec, Canada.

SUBJECTS

Patients undergoing thyroidectomy and CCND for nodules suspicious for thyroid cancer (June 2009 to May 2010).

METHODS

Retrospective analysis of 157 patients who underwent thyroidectomy and analysis of CCND as a function of sentinel lymph node status on frozen section as determined by a pathologist at one of the participating centers.

RESULTS

Three patients were considered true failures or false negatives of the original protocol. These 3 patients were deemed to have benign lymph node status intraoperatively but were found postoperatively to harbor malignancy and therefore should have undergone CCND. The critical reasons for the imperfect false-negative rate are believed to be secondary to samples falsely deemed benign as well as multinodular disease.

CONCLUSION

The value of sentinel lymph node biopsy in thyroid cancer, although largely debated, appears to be strong. If caution is taken in using dedicated head and neck pathologists for sentinel lymph node cases, as well as properly addressing multinodular malignancy, clinical decision making can be rendered more objective.