Incomplete Thyroid Ultrasound Reports Lead to Unnecessary Biopsies

Leesburg, VA, December 19, 2018—There is widespread underreporting of established elements in thyroid ultrasound (US) reports, leading to confusion and discrepancy among clinical specialists regarding the risk of malignancy and the need for biopsy, according to an article in the December 2018 issue of the American Journal of Roentgenology (AJR).

Thyroid nodules are exceedingly common, with a reported prevalence of 30–60% in autopsy series and 10–68% in adults undergoing thyroid US. However, most thyroid nodules are benign, and even small malignant nodules exhibit indolent behavior. Although the incidence of thyroid cancer has increased dramatically worldwide, the mortality rate associated with thyroid cancer has remained stable and very low, with an overall 5-year survival of 98.2%. These factors have led investigators to argue that there is an epidemic of overdiagnosis, which is largely attributed to the widespread increased use of imaging.

A retrospective review was conducted of thyroid US examinations performed between January and June 2013 in Nova Scotia, Canada. Baseline examinations that identified a nodule were evaluated for 10 reporting elements. Reports that lacked a comment regarding malignancy risk or a recommendation for biopsy were considered unclassified and were graded by three clinical specialists in accordance with the 2015 American Thyroid Association management guidelines. A radiologist reviewed the images of unclassified nodules, and on the basis of radiologic grading, biopsy rates and pathologic findings were compared between nodules that did and did not warrant biopsy.

Of 971 first-time thyroid US studies, 478 detected a nodule. The number of reports lacking a comment on the 10 elements ranged from 154 to 433 (32–91%). A total of 222 nodules (46%) were unclassified, and agreement in assigned grading by the clinical specialists was very poor. According to radiologist grading, only 57 of 127 biopsies were performed on nodules that warranted biopsy, and 16 of 95 biopsies were performed unnecessarily. On the basis of the three clinical specialists' interpretation, 10, 31, and 33 reports were considered too incomplete to assign a grade; 40, 10, and four biopsies would have been unnecessarily ordered; and zero, three, and four cancers would have been missed.

The results show how incomplete reports lead to inaccuracies regarding true malignancy risk and confusion regarding management. These results reinforce the need for radiologists to incorporate evidence-based guidelines and, preferably, a standard when reporting thyroid US examinations, particularly when assigning the risk of malignancy and recommending the need for biopsy.

Founded in 1900, ARRS is the first and oldest radiology society in the United States, and is an international forum for progress in radiology. The Society's mission is to improve health through a community committed to advancing knowledge and skills in radiology. ARRS achieves its mission through an annual scientific and educational meeting, publication of the American Journal of Roentgenology (AJR) and InPractice magazine, topical symposia and webinars, and print and online educational materials. ARRS is located in Leesburg, VA.