Clinical Thyroidology® for the Public
Summaries for the Public from recent articles in Clinical Thyroidology
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THYROID NODULES
Could my toxic nodule be cancer?
BACKGROUND
Thyroid nodules are common, occurring in up to 50% of individuals. The concern about any thyroid nodule is whether it is cancer. Overall, only ~5% of nodules are cancerous. An essential step in evaluating nodules is performing a thyroid ultrasound. The American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) classifies nodules on the basis of thyroid ultrasound. A thyroid biopsy is then recommended based on the ACR TI-RADS classification.
One exception to this is if the nodule(s) is/are active in producing thyroid hormone at high levels. This is known as a toxic nodule if there is a single nodule and a toxic multinodular goiter if there are multiple toxic nodules. A toxic nodule is usually diagnosed by a thyroid scan. The likelihood that a toxic nodule was also a cancer has been assumed to be extremely low. Indeed, current guidelines suggest that a biopsy to determine if a cancer is present is not needed if a nodule is overactive.
One concern about toxic nodules is that the ACR TI-RADS classification system to determine which nodules should be biopsied has not been extensively validated in toxic nodules. The present study aimed to evaluate the ACR TI-RADS classification system in toxic nodules and to determine how often cancer does occur in toxic nodules.
THE FULL ARTICLE TITLE
Koelliker E, et al. Sonographic and pathologic features of malignant hot thyroid nodules: a multi-institutional study. Surgery 2026;189:109710.
SUMMARY OF THE STUDY
This was a study conducted at five academic hospitals. Patients who underwent thyroid surgery between January 2017 and March 2024 with a diagnosis of hyperthyroidism due to toxic nodules were included. Toxic nodules were identified by thyroid scans. Nodules smaller than 1 cm and those without both an ultrasound and thyroid scan prior to surgery were excluded. Ultrasound features were recorded from radiology reports or by consensus review of images by two investigators and the nodules were characterized by ACR TI-RADS. Final diagnoses were based on surgical pathology.
A total of 257 patients with 323 toxic nodules were included. Overall, 11 nodules (3.4%) were cancer. Cancer was significantly more common in single toxic nodules than in toxic multinodular goiters (7.3% vs. 1.0%). Compared to benign hot nodules, cancerous hot nodules were more often solid (90.9% vs. 51.6%) and isoechoic or hyperechoic (81.8% vs. 48.4%) and had lobulated or irregular margins (27.3% vs. 2.9%). Although ACR TI-RADS classification did not differ significantly between groups, all cancerous toxic nodules met ACR TI-RADS criteria for biopsy. At least one high-risk pathology feature was present in all cancerous nodules.
WHAT ARE THE IMPLICATIONS OF THIS STUDY?
This study confirms that cancer occurring within a toxic nodule is rare and almost all of the cancers were in single toxic nodules. The cancers in toxic nodules were found to commonly exhibit aggressive, high-risk features. All of the toxic nodules containing cancer had ultrasound characteristics that were high risk by ACR TI-RADS criteria. These data suggest that toxic nodules with high risk ACR TI-RADS criteria should be biopsied prior to planned treatment.
— Alan P. Farwell, MD
ATA RESOURCES
Thyroid Nodules: https://www.thyroid.org/thyroid-nodules/
Hyperthyroidism (Overactive): https://www.thyroid.org/hyperthyroidism/
Thyroid Cancer (Papillary and Follicular): https://www.thyroid.org/thyroid-cancer/
ABBREVIATIONS & DEFINITIONS
Thyroid nodule: an abnormal growth of thyroid cells that forms a lump within the thyroid. While most thyroid nodules are non-cancerous (Benign), ~5% are cancerous.
Toxic nodule: characterized by one overactive nodule or lump in the thyroid that may gradually grow and increase their activity so that the total output of thyroid hormone in the blood is greater than normal.
Toxic multinodular goiter: characterized by two or more overactive nodules or lumps in the hormone in the blood is greater than normal.
Hyperthyroidism: a condition where the thyroid gland is overactive and produces too much thyroid hormone. Hyperthyroidism may be treated with antithyroid meds (Methimazole, Propylthiouracil), radioactive iodine or surgery.
Thyroid Ultrasound: a common imaging test used to evaluate the structure of the thyroid gland. Ultrasound uses soundwaves to create a picture of the structure of the thyroid gland and accurately identify and characterize nodules within the thyroid. Ultrasound is also frequently used to guide the needle into a nodule during a thyroid nodule biopsy.
Thyroid biopsy: a simple procedure that is done in the doctor’s office to determine if a thyroid nodule is benign (non-cancerous) or cancer. The doctor uses a very thin needle to withdraw cells from the thyroid nodule. Patients usually return home or to work after the biopsy without any ill effects.
Thyroid scan: this imaging test uses a small amount of a radioactive substance, usually radioactive iodine, to obtain a picture of the thyroid gland. A “cold” nodule means that the nodule is not functioning normally. A patient with a “cold” nodule should have a fine needle aspiration biopsy of the nodule. A “functioning”, or “hot”, nodule means that the nodule is taking up radioactive iodine to a degree that is either similar to or greater than the uptake of normal cells. The likelihood of cancer in these nodules is very low and a biopsy is often not needed.
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