Criteria for follow-up of thyroid nodules diagnosed as follicular neoplasm without molecular testing – The experience of a high-volume thyroid centre in Japan

Abstract

Background: Clinical management of follicular neoplasms (FNs) using molecular testing of thyroid-aspirated materials is not routinely performed in Japan. This article aims to identify low-risk FN nodules that can be followed up without molecular testing. Methods: The relationship between preoperative findings, factors influencing surgical decision, and the risk of malignancy (ROM) was examined in 356 thyroid nodules with cytological diagnosis of FN at Kuma Hospital from January to December 2020. Results: ROMs of FN with cytology results favouring malignancy (41.2%) were significantly higher than those favouring benign (7.7%) or borderline (8.2%) (p <30 mm; 3.6%, ≥30 mm; 20.0%). ROMs of FNs with a tumour volume doubling rate (TVDR) of 1.0/year or more (28.6%) were higher than those of FNs with a lower TVDR (9.9%) (p <30 mm and TV-DR <1.0/year, are considered low risk and can be followed up without the need for molecular testing.