New data on angio invasive follicular thyroid cancer necessitates change in ATA guidelines

With the publication of an article from Japan involving study of 303 cases of encapsulated angioinvasive FTC the current ATA risk classification of angioinvasive into those with four or more instance of angioinvasion ( deemed high risk) and those with three or less (deemed low risk) needs to be revised. The ATA risk classification is low, intermediate and high and the recommendations for each vary considerably.The current guidelines indicate that a patient with 4 or more angio invasions is high risk and a patient with 3 0r less foci of angioinvasion is consdiered low risk and therfore not needing remant ablation. Yamazaki et (1) reviewed 290 cases of FTC with angioinvasion (AI).These patients were free of metastasis at presentation and were seen at the Ito hosptial from 2005 to 2014. Disease free survival in those with one AI had a 94.9 % 10 year DFS while a patient with 4 or more had a 83% DFS, Those with AI of 1-3 had a DFS of 86.3 while patients with 4 or more had a DFS of 83.3 This is not statistically significant. Patients with angioinvasion of less than 4 are consdiered low risk by the ATA criteria Yamazaki' data show there is not a prognostic difference between a patient with three and a patient with four foci of AI . Yamazali et al Encapsulated angioinvasive follicular thyroid cancer.Prognostic impact of the extent of vascular invasion.Ann Surg Oncol 2022 feb 25