RESUMO
OBJECTIVE: Thyroid cancer is the most common type of endocrine-related cancer worldwide. The aim of this article was to assess the relationship between thyroid diseases diagnosed by fine needle aspiration (FNA) and family history of thyroid disease. DESIGN: The study was conducted in a tertiary high-volume thyroid cancer centre. Fine needle aspiration (FNA) of a thyroid nodule detected on neck ultrasound for any reason was performed in all included patients. PATIENTS: A total of 10 709 patients were included in the study. MEASUREMENTS: Correlation of cytological findings classified according to the Bethesda system and family history was calculated using Fisher's exact test. RESULTS: There were 2580 (24.09%) patients with non-malignant thyroid diseases in the family and 198 (1.85%) patients who had a history of thyroid cancer in the family. A total of 2778 (25.94%) patients had positive family history of thyroid diseases, and 7931 (74.06%) patients had negative family history. In patients with papillary thyroid carcinoma in family history, the difference between those with benign (Bethesda 2) and malignant thyroid FNA diagnosis (Bethesda 6) was found to be statistically significant (P = .0432). CONCLUSIONS: Family history plays a significant role in the development of thyroid cancer, and having first-degree relatives with not only medullary, but also papillary thyroid cancer strongly predicts the risk of developing the malignant thyroid disease. In contrast, benign thyroid disorders in family history do not lead to the development of thyroid cancer.