Association between Serum Thyrotropin Concentration and Thyroid Nodules Malignancy

Background and purpose: Thyroid nodules are quite common witch are found in clinical or ultrasound examinations. They are detected in 4-8% of clinical examinations and 7-15% are malignant. TSH is one of the growth factors for nodule growth. Controversial reports are published on the effect of TSH on thyroid nodule malignancy. This study aimed at investigating the effect of TSH in predicting malignancy in thyroid nodules. In this cross sectional research, 500 patients were studied. Serum TSH level was measured prior to fine needle aspiration (FNA). Data analysis was done applying inferential statistics. The patients were 457 (91.4%) females and 43 (8.6%) males and the mean age was 43.43±13.9 years. Among the patients 240 had single nodule and 260 had multiple thyroid nodules (P=0.08). The mean size of nodules in benign and malignant nodules were 26.1±12.2 and 27.3±9.8 mm, respectively (P=0.6). Malignant and benign nodules were observed in 31 (6.2%) and 469 (93.8%) patients. Mean TSH level was 3.3±6.9 and 2.4±2 in patients with benign and malignant nodules, respectively (P= 0.47). To investigate the association between TSH and FNA cytology, TSH levels were divided into <0.5, 4.9-0.5, and ≥5 using person correlation. This study showed no significant difference between the three groups (P= 0.3). TSH alone is not a suitable marker for predicting thyroid malignancy.