Risk of malignancy in fine-needle aspiration biopsy in patients with thyroid nodules.

INTRODUCTION Fine-needle aspiration biopsy (FNAB) is the cornerstone of thyroid nodule evaluation. In most cases, FNAB can discriminate between benign and malignant disease. In other cases, it is only indicative of malignancy and the results are considered "suspicious". In Denmark, thyroid FNAB results are categorised into six groups: "inadequate", "cystic", "inconclusive", "benign", "suspicious" and "malignant". The risk of malignancy in the Danish "suspicious" group is of interest for patients as well as doctors participating in the diagnosis and treatment. The Danish Thyroid Surgery Database (THYKIR) registers preoperative thyroid FNAB and final histology. The aim of this study was to assess the malignancy risk among patients with a suspicious thyroid FNAB according to the Danish criteria and to identify possible predictors of malignant histology. METHODS A prospective cohort counting 483 patients with a "suspicious" thyroid FNAB who had been treated surgically in The Region of Southern Denmark in the 2001-2013 period was retrieved from the THYKIR database. RESULTS The risk of malignancy in the Danish thyroid FNAB "suspicious" group is 22%. Serum thyroid-stimulating hormone outside the normal range and vocal cord palsy may be patient-related predictors of malignancy. CONCLUSION Awaiting the introduction of reliable tools for preoperative evaluation, the current practice with histo-logical clarification of the "suspicious" thyroid FNAB seems justified. FUNDING none. TRIAL REGISTRATION not relevant.