The Prospective Implementation of the 2015 ATA Guidelines and Modified ATA Recurrence Risk Stratification System for Treatment of Differentiated Thyroid Cancer in a Canadian Tertiary Care Referral Setting.

Objective: To present clinical outcomes of the prospective implementation of the 2015 American Thyroid Association (ATA) guidelines for the management of thyroid nodules and differentiated thyroid cancer (DTC) using the modified ATA recurrence risk (RR) stratification system. Methods: We prospectively analyzed 612 patients with DTC treated between April 2017 and December 2021 in Calgary, Alberta. Each patient was prospectively assigned a modified ATA RR and American Joint Committee Cancer 8th edition stage. Initial risk stratification and consideration of the 2015 ATA guidelines guided surgical management as well as the indication for and dose of radioiodine (RAI) and other adjuvant therapies. Patients were assessed for their response to treatment (RTT) at 2-years postoperatively. Results: There were 479 patients who had 2-year follow-up data and were included in the study. Of these patients, there were 253 (53%) low-, 129 (27%) intermediate-, and 97 (20%) high-RR patients. Of these, 227 patients (47%) underwent total thyroidectomy (TTX) plus RAI, 178 (37%) underwent TTX only, and 74 (16%) underwent lobectomy. The RTT at 2 years was excellent for 89% (66) of patients with lobectomy, 84% (149) for TTX only, and 53% (121) for TTX plus RAI. Among 253 patients who were deemed low RR, 85% (216) had excellent RTT, 13% (32) indeterminate RTT, 2% (4) biochemical incomplete RTT, and 1 patient had structural incomplete RTT. The intermediate RR group had the following RTT outcomes: 64% (83) excellent, 23% (30) indeterminate, 6% (7) biochemical incomplete, and 7% (9) structural incomplete. The high RR group had the worst RTT outcomes, with 38% (37) excellent, 19% (18) indeterminate, 10% (10) biochemical incomplete, and 33% (32) structural incomplete RTT. Conclusions: The 2015 ATA RR stratification system is useful for predicting disease status at 2-year post-treatment in patients with DTC. The 2015 ATA guidelines and modified ATA RR stratification treatment recommendations may reduce thyroid cancer overtreatment by including lobectomy as a definitive treatment option for low-risk thyroid cancers and selective use of RAI for intermediate and high-risk patients.

Thyroid nodule ultrasound reports in routine clinical practice provide insufficient information to estimate risk of malignancy.

PURPOSE: Ultrasonographic characteristics of thyroid nodules play an important role in estimating the risk of malignancy (ROM). Guidelines mandate all thyroid nodules be characterized by six key ultrasonographic features to estimate the ROM. Our objective was to evaluate how frequently these characteristics were identified by radiologists and the ensuing utility to estimate ROM. METHODS: We retrospectively reviewed 1930 consecutive diagnostic thyroid ultrasound reports from a large community radiology practice. A total of 1339 individual patients were found to have one or more thyroid nodules. Each report was analyzed for six key ultrasonographic features. A utility score (UtS) was calculated (range 0-6) with a single point given for a comment on each feature. RESULTS: Of the 1339 patients, 75% of the studies reported more than one nodule (mean number of nodules = 3.4). Mean maximal diameter of the largest nodule per patient = 1.8 cm. The mean UtS was 2.57. Nodule size did not influence the UtS.: Nodule <1 cm (UtS: 2.53), 1-2 cm (UtS: 2.68) and >2 cm (UtS: 2.49). We believe a UtS of four or greater is needed to confidently estimate ROM: we found this in 13.7% of reports. CONCLUSIONS: Our retrospective analysis of a large number of consecutive thyroid ultrasound reports in routine clinical practice suggests that the vast majority provide insufficient information to allow the clinician to risk stratify the nodules by estimating the ROM. This could lead to both over-diagnosis and over-treatment of benign/indolent thyroid lesions or under-diagnosis of clinically important thyroid cancers.