Great veins invasion in follicular thyroid cancer: single-centre study assessing prevalence and clinical outcome.

Purpose: Great veins invasion is considered as a rare and prognostically unfavourable event in thyroid cancer. However, current knowledge about this issue is mainly based on single case reports. Follicular thyroid cancer (FTC) represents the histotype with the most pronounced angioinvasive feature. This study is aimed at assessing the actual prevalence of great veins invasion in FTC and providing information about prognosis and the proper clinical management of these patients.
Methods: Clinico-pathological and radiological data of patients with thyroid cancer undergoing thyroidectomy in our institution were retrospectively retrieved. Inclusion criteria were as follows: (a) histological diagnosis of FTC; (b) instrumental and histological evidence of great veins invasion and (c) documented follow-up entirely performed at our institution. Pre-surgical assessment of great veins status was performed in all patients by means of Doppler ultrasonography.
Results: Out of 637 patients operated from 2003 to 2013, four subjects, all affected with FTC, showed great veins involvement (0.62% of the overall cohort and 7.85% of the FTC group). One of them was lost at follow-up. All three patients with available follow-up were subjected to aggressive surgery obtaining a complete eradication of neck disease. All of them achieved the 5-year survival target (60, 63 and 96 months of survival for patients 1, 2 and 3, respectively).
Conclusions: Great veins invasion may not be uncommon in FTC and preoperative detection and characterisation of such condition may optimise surgical approach and improve survival.