Thyroid nodules: Avoiding overdiagnosis while detecting clinically significant cancer

Abstract

Most thyroid nodules are benign, and many thyroid cancers are indolent. The goal is therefore not to diagnose every nodule but to identify the most likely to represent clinically significant thyroid cancer while minimizing unnecessary biopsy, surgery and lifelong treatment. For initial clinical assessment, we should look for childhood or therapeutic neck radiation, history of thyroid cancer, rapidly enlarging neck mass, hoarseness of voice or vocal-cord dysfunction, dysphagia or compressive symptoms, previous thyroid cancer, suspicious cervical lymphadenopathy. We will have to assess the nodule characteristics, fixation to the underlying structure, cervical lymph nodes and signs of local invasion. Serum TSH is the initial biochemical test, and ultrasound is the central risk-stratification tool. The ultrasound will tell us about the composition, echogenicity, shape and margin of the nodule; it also tells us about microcalcifications, peripheral or rim calcification, punctate echogenic foci and the adjacent cervical lymph nodes. American College of Radiology Thyroid Imaging Reporting and Data System (ACR-TIRADS) and EU-TIRADS are standardized point-based systems used by radiologists to evaluate thyroid nodules on ultrasound. These systems guide decisions on whether a nodule requires a fine-needle aspiration biopsy, routine ultrasound follow-up or no further evaluation. Bethesda categories define a nodule as non-diagnostic, benign, Atypia of undetermined significance, follicular neoplasm, suspicious for malignancy and malignant nodule. A cytology category represents an estimated probability of malignancy that must be interpreted together with ultrasound risk, clinical risk, patient preference and molecular testing where appropriate. Overdiagnosis of a cancer is a matter that would never have caused symptoms or death during the patient’s lifetime. Aggressive investigation may lead to unnecessary FNA, repeated imaging, diagnostic surgery, thyroidectomy-related complications, lifelong thyroid hormone therapy and the psychological burden of a cancer diagnosis.

[J Assoc Clin Endocrinol Diabetol Bangladesh, 2026;5(Suppl 1): S5]