Preoperative ultrasound characteristics in determining the likelihood of requiring completion thyroidectomy for cytologically confirmed (Bethesda VI) papillary thyroid tumors with 1 – 4 cm in diameter

Abstract

Background: Papillary thyroid carcinoma (PTC) is the most commonly diagnosed differentiated thyroid carcinoma. There is controversy about performing upfront lobectomy vs thyroidectomy for smaller well differentiated thyroid carcinoma. Methods: A retrospective study from 2015 to 2020 was conducted consisting of consecutive patients with a preoperative malignant (Bethesda VI) cytology on fine needle aspirate (FNA) consistent with PTC. Specific ultrasonographic features such as taller than wide, hypoechogenicity, irregular margins, internal vascularity and microcalcifications were recorded. Criteria for exclusion was the presence of positive lymph nodes, extrathyroidal extension, familial thyroid carcinoma and bilateral disease detected preoperatively. Outcome was defined as a lobectomy being adequate treatment or a completion thyroidectomy recommended based on current 2015 ATA guidelines. Results: Preoperative malignant cytological nodules (Bethesda VI) with irregular margins on sonography were significantly (p = 0.025) at increased risk (OR = 2.48) of requiring a completion thyroidectomy. There was also no statistically significant difference between groups when stratified by size with 50% of tumours between 1 and 2 cm requiring a completion thyroidectomy. Conclusions: The presence of irregular margins on ultrasound predicts an increased risk of requiring a completion thyroidectomy. Specific consideration of this sonographic finding should be made when counselling patients who have cytologically confirmed papillary thyroid carcinoma regarding the best choice of thyroid operation.

Keywords

• Differentiated thyroid carcinoma
• Irregular margins
• Extrathyroidal extension