TSH Level and Risk of Malignancy in Patients with Bethesda Category IV Thyroid Nodules

Abstract

Fine needle aspiration biopsy does not permit to distinguish between benign and malignant follicular thyroid lesions (category IV in the Bethesda Cytopathology System). Some reports have suggested an association between increased serum TSH levels and thyroid cancer, so the aim of this study was to investigate the association between TSH levels and malignancy in patients with follicular thyroid nodules. Therefore, we conducted a retrospective study of all subjects who underwent surgical treatment for Bethesda IV thyroid nodules in a single center (years 2012-2017). A total of 127 patients were analyzed, and malignancy was present in 38.6% of the patients. Using ROC analysis, the best TSH cut-off point to differentiate benign from malignant disease was 2.1 mU/l and the age cut-off with better sensitivity and specificity was 47 years. The proportion of subjects with TSH ≥ 2.1 mU/l was greater among subjects with cancer than in those with benign diseases (65.3 vs 44.9%, P = 0.029). The concurrence of both cut-off points (TSH ≥ 2.1 mU/l and age ≥ 47 years) showed a higher diagnostic accuracy than either of the two variables separately. Therefore, the present study supports an association between serum concentrations of TSH and risk of malignancy among subjects with Bethesda IV thyroid nodules. TSH levels could modify the diagnostic and therapeutic approach of patients with Bethesda IV nodules.

Monitoring Thyrotropin in Veterans With Thyroid Nodules

“…One study suggested that a thyrotropin cutoff point of ≥ 2.1 mU/I and an age cutoff point of ≥ 47 years were significantly associated with a diagnosis of malignancy. 7 Although the current study did not study malignancy, the results showed that the mean age at nodule diagnosis was higher in patients who had abnormal vs normal most recent thyrotropin levels: 69 vs 62 years, respectively. Future studies could determine whether a certain initial thyrotropin value or age could be used as a cutoff for requiring further thyrotropin monitoring to check for development of hyperthyroidism or hypothyroidism.…”

The current assessment and management of thyroid nodules

“…Measurement of serum TSH is the initial laboratory test for all patients with thyroid nodules. Normal or elevated levels of TSH express a nonfunctioning nodule, and in large studies are associated with a higher risk of thyroid cancer [16,17]. Low or suppressed levels are associated with hyperthyroidism and a radioisotope scan with iodine-123 or technetium-99m pertechnetate must be performed.…”

Thyroid Nodules and Obesity

“…It triggers the secretion of IGF-1, and insulin regulates the expression of thyroid genes to control the proliferation and differentiation of thyroid cells. Furthermore, expression of TSH receptors in extrathyroidal tissues (specifically in adipose tissue) means that TSH can promote the differentiation of pre-adipocytes to mature adipocytes, and in the presence of insulin, TSH exerts mitogenic properties [ 12 ]. In this review, we summarize the latest evidence regarding the molecular links between obesity and thyroid cancer development and discuss emerging diagnostic and therapeutic implications.…”