Incidence of thyroid function test abnormalities in patients receiving immune checkpoint inhibitor therapy for cancer: A single institution retrospective review.

Abstract

e14569 Background: With the advent of immune-checkpoint inhibitor (ICI) therapy, thyroid function test abnormalities (TFTA) are common with reported incidence range of 2-15%. Our aim was to describe the incidence of TFTAs retrospectively in patients (pts) on ICI therapy. Methods: 285 pts reviewed (178 male, 107 female; ages 16-94) of which 218 had no baseline TFTA, 61 had baseline TFTAs, and 6 had thyroidectomy (excluded). Pts received at least one dose of ipilimumab (I) and/or nivolumab (N) or pembrolizumab (P). Post-treatment TFTA was classified according to definitions of thyroid abnormalities when possible. Results: A total of 35% (76/218) pts had new onset TFTAs on ICI. Of note, 70.5% (43/61) had baseline TFTA that were exacerbated by ICI. Median time to new onset or exacerbated baseline TFTA were 46 & 33 days respectively. Of note, 65% (20/31) of pts on both I+N had new onset TFTA, compared to 31.3% (15/48) with I, 31.5% (28/89) N, 26% (13/50) P. Conclusions: Incidence of TFTAs with ICI was higher than expected in our pts. Pts with baseline TFTA and/or I+N combination therapy had higher incidence of TFTA than one agent ICI therapy. In conclusion, we recommend more frequent evaluation of TFT in the first two months, especially in those with baseline TFTA. [Table: see text]