The significance of unrecognized histological high-risk features on response to therapy in papillary thyroid carcinoma measuring 1-4 cm: implications for completion thyroidectomy following lobectomy.

The prevalence of unrecognized histological HRFs under the current recommendations is relatively high among 1-4 cm PTCs. Among the unrecognized histological HRFs, LVI was the only one which independently associated with an incomplete response (i.e. posing an increased risk of persistent/recurrent disease after curative surgery). These findings may have implications for patients who undergo lobectomy for 1-4 cm PTCs with no clinically recognizable HRFs under the current recommendations.