FOLLICULAR THYROID CARCINOMA - CLINICAL AND DIAGNOSTIC FINDINGS IN A 20-YEAR FOLLOW UP STUDY.

CONTEXT: Follicular thyroid carcinomas (FTC) represent 6-10 % of all thyroid carcinomas; the evolution of FTC is quite controversial, partly due to frequent changes of the histopathological definition (minimally invasive-MIFTC or widely invasive carcinoma-WIFTC) and treatment strategies adjustments. OBJECTIVE: This research aims to examine the diagnostic procedure, therapeutic attitude and survival rates of patients with FTC, over a period of 16 years in the same institution, with a follow-up of at least 4 years, by analyzing correlations between histology subtype, treatments and the rate of recurrent disease. SUBJECTS AND METHODS: We have studied 5891 patients with thyroid carcinomas who have undergone surgical or oncological treatment within the institution, between 1st January 2000 - 31st December 2015; among them we found 133 patients (2.25%) with "pure" follicular thyroid carcinoma: 114 (86%) women and 19 (14%) men, with a female-male ratio of 6:1. The age of the patients ranged from 10 to 76 years, with an average of 47.8 years. Statistical analysis was done comparing differences among groups of MIFTC and WIFTC. RESULTS: There was an unexpected high percentage of WIFTC and also an increased number of biochemically persistent and/or recurrent disease in patients with MIFTC. A stronger correlation was observed with the tumour dimensions, rather than with the histopathological subtype. CONCLUSIONS: This research observed that overall survival was associated with tumour size rather than histopathological subtype and there is an important need to perform further studies to assess the effectiveness of treatment strategies.