SAT-LB099 Optimal Timing of Follow Up for Cytologically Benign Thyroid Nodules

Abstract

Background: Thyroid nodules are common, and studies show that 85-95% of thyroid nodules are benign. Current ATA guidelines recommend continued follow up of FNA benign thyroid nodules within 24 months, due to a 0-3% false negative rate. Some studies have shown safety and efficacy of longer follow up periods, however these studies are comprised of mostly younger females. Within our institution, we sought to analyze the long term follow up data for FNA benign thyroid nodules to see if follow up within 24 months was necessary to provide safe and effective detection of false negative thyroid cancers in our predominantly older, male population. Methods: Retrospective chart review involving all patients at our institution who had a new FNA benign thyroid nodule diagnosed from 1/1/2010-12/31/2017. Data regarding long-term outcomes were recorded, including number of follow up ultrasounds, repeat FNAs, thyroidectomy, diagnosis of thyroid cancer, and cause of death. Results: 827 new FNA benign nodules, from 609 patients, where diagnosed between 2010 and 2017. Of these, 6 FNA benign nodules from 5 patients were excluded given an abnormal FNA in a separate nodule. These 5 patients underwent thyroidectomy and therefore did not require long term follow up of their FNA benign nodule. Of the remaining 821 nodules from 604 patients, 84% were male with mean age of 63. 488 of the 821 nodules (59%) were followed up with US, repeat FNA or thyroidectomy, while 333 (41%) had no dedicated follow up. Eighty-eight percent of nodules that had follow up received it within 24 months. In patients who received follow up, there were 6 new thyroid cancers diagnosed during the study period. Two cancers were found incidentally on thyroidectomy done for compressive symptoms, 1 cancer was found in a new nodule during follow up, and 3 were related to a false negative FNA (0.6% of all nodules). All patients with a false negative FNA were still alive after a mean follow up time of 3.3 years. No patients who received first follow up at >24 months were diagnosed with thyroid cancer. Nodules that received no dedicated thyroid follow up received a mean clinical follow up time of 3.5 years, during which there was no development of clinically evident thyroid cancer. 72 patients died during the follow up time, none related to thyroid cancer. Conclusion: In our older, largely male population, the false negative thyroid FNA rate is low at 0.6%. No patients in this cohort died of thyroid cancer related causes during a mean follow up period of 4 years. No patients who received dedicated nodule follow up after 24 months were found to have thyroid cancer, and of the 333 benign nodules that had no dedicated follow up, none presented with any evidence of clinically significant thyroid cancer during a mean follow up of 3.5 years. Based on this evidence, it is likely safe to extend the follow up time of benign thyroid nodules to over 24 months. Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. s presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.