Correct extent of thyroidectomy is poorly predicted preoperatively by the guidelines of the American Thyroid Association for low and intermediate risk thyroid cancers.

BACKGROUND: Recent guidelines from the American Thyroid Association recommend thyroid lobectomy for intrathyroidal differentiated thyroid cancers <4 cm. Our aim was to examine histology from patients with cytologic results that were positive or suspicious for malignancy to assess the extent of initial thyroidectomy based on criteria from the 2015 American Thyroid Association guidelines.
METHODS: We studied consecutive patients who had either a positive or suspicious for malignancy cytologic diagnosis and under prior American Thyroid Association guidelines underwent initial total thyroidectomy ± lymphadenectomy.
RESULTS: Among 447 patients, high-risk features necessitating total thyroidectomy were present in 19% (72/380) of positive and 15% (10/67) of suspicious for malignancy patients (P = .5). Intermediate-risk features on histology were identified postoperatively in 46% (175/380) with positive and 15% (18/67) with suspicious for malignancy fine-needle aspiration results. In multivariable analysis, preoperative factors associated with intermediate-risk disease included age ≥45 years, women, larger tumor size, positive fine-needle aspiration cytology, and BRAF V600E or RET/PTC positivity.
CONCLUSION: When patients are considered for lobectomy under the 2015 American Thyroid Association guidelines, ~ 60% with positive and 30% with suspicious for malignancy cytology would need completion thyroidectomy based on intermediate-risk disease. The cost and risk implications of the new American Thyroid Association strategy were substantial and better tools are needed to improve preoperative risk stratification.