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A new thyroid nodule electronic tool to guide management decisions

CTFP October 2021

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Thyroid nodules are very common in the general population and increase with age. More than 90% of thyroid nodules are benign (non-cancerous) and do not result in any symptoms, while many of the nodules that prove to be cancer are low risk with an excellent prognosis requiring only thyroid surgery or no treatment. It is important to distinguish low-risk from high-risk thyroid nodules to appropriately diagnose and treat thyroid cancer and avoid excessive evaluation and unnecessary surgery for low risk nodules. Medical societies have provided recommendations to determine the cancer risk and improve the evaluation and treatment of thyroid nodules using a combination of variables, including the clinical presentation, blood thyroid tests, ultrasound features, biopsy results and molecular tests. Given the multiple variables involved, the evaluation of thyroid nodules is becoming increasingly complex and difficult to complete.

A task force of the American Association of Clinical Endocrinology (AACE) and Associazione Medici Endocrinologi (AME), including members from the United States and Europe met over a 3-year period to update the clinical practice guidelines for thyroid nodule care. The task force created a Web-based tool to provide guidance on the initial evaluation and treatment of patients with thyroid nodules. The article describes the development and details of this novel electronic tool.

Garber JR et al 2021 American Association of Clinical Endocrinology and Associazione Medici Endocrinologi thyroid nodule algorithmic tool. Endocr Pract 27:649–660. PMID: 34090820.

The tool, termed TNAPP (Thyroid Nodule App, pronounced “tee nap”) is available online at https://aacethyroid. It provides recommendations for the initial treatment of a typical patient presenting with a thyroid nodule with an average risk for cancer. It was not designed to be used for patients at risk of having aggressive or advanced types of thyroid cancer. The tool uses 26 clinical factors, 36 ultrasound features, and 48 biopsy features associated with a greater or lesser risk of cancer.

A thyroid biopsy is the procedure of choice to identify suspicious thyroid nodules that require surgery. Clinical factors can be used to weigh for or against performing a biopsy. The ultrasound characteristics of thyroid nodules are the main variables used to determine the cancer risk and decide whether a biopsy is indicated. Each ultrasound feature has been assigned points based on the associated risk of cancer. Based on this numeric scoring system, thyroid nodules are categorized as having low, intermediate and high risk of cancer. A library of ultrasound images and cartoons was created to help with the ultrasound classification. The tool provides a recommendation to perform a biopsy or when to repeat ultrasound monitoring if necessary.

Cytologic features can also be entered in the algorithm if a biopsy was performed, to further determine the cancer risk. The six cytology categories (I-VI) of the Bethesda System for Reporting Thyroid Cytopathology are used with certain subcategories.

The AACE/AME TNAPP is a new, easy-to-use, electronic tool available online to provide recommendations for thyroid nodule management. The tool can be modified in the future as new information becomes available and guidelines change. The development of TNAPP represents an innovative way to disseminate evidence-based guidelines for thyroid nodule care. Future studies are needed to validate the accuracy of the TNAPP results.

— Alina Gavrila, MD, MMSc

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Thyroid nodule: an abnormal growth of thyroid cells that forms a lump within the thyroid. While most thyroid nodules are non-cancerous (Benign), ~5-10% are cancerous (Malignant).

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 cytology: the cells obtained from the FNA are prepared for optimal preservation and examined with a microscope to assess whether they are normal or show features of disease.