Thyroid dysfunction in lung cancer patients treated with immune checkpoint inhibitors (ICI): Role of race, gender, and concurrent chemotherapy in a multiethnic urban cohort.

Abstract

e21622 Background: Immune-related adverse events (irAE) associated with ICI have been reported, but remain poorly understood. We sought to characterize patterns of thyroid dysfunction—one of the most common irAE—in a large cohort of ethnically-diverse lung cancer patients treated with ICI. Methods: A retrospective chart review of lung cancer patients receiving an anti-PD1 or PD-L1 agent from January 2016 to July 2019 was performed. Subjects included had normal baseline thyroid function. Thyrotoxicosis and hypothyroidism was defined as thyroid-stimulating hormone level less than 0.4 and greater than 4.6, respectively. Time to event analysis with inverted Kaplan Meier curves and log-rank tests were used to compare thyroid dysfunction among race, gender, and treatment subgroups. Results: We identified 256 subjects: 206 had normal baseline thyroid function and 76 went on to develop thyroid dysfunction. Rates of thyroid dysfunction by one year occurred at similar frequencies among all races. Thyrotoxicosis occurred at significantly higher rates in Black (25, 31.7%) than in White (8, 12.9%) and Hispanic (7, 16.7%) subjects. In contrast, hypothyroidism occurred more often in White (13, 21.0%) and Hispanic (18, 42.9%) than in Black (12, 15.2%) subjects. Gender and concurrent chemotherapy showed no significant association with thyroid dysfunction. Of subjects with thyrotoxicosis (N = 42), hypothyroidism followed in 33.3% (N = 14) with 1 subject receiving methimazole and 13 levothyroxine. In those subjects, median time to thyrotoxicosis and hypothyroidism was 4.0 and 7.2 weeks, respectively. Conclusions: Despite the higher prevalence of non-ICI-related thyroid disease among females and the anticipated immunosuppressive effect of chemotherapy, neither gender nor chemotherapy correlated with thyroid dysfunction; however, race did. Black subjects exhibited significantly higher rates of thyrotoxicosis. Our findings are consistent with prior research showing that thyrotoxicosis, including Graves’ disease, occurs more often in Blacks. While the pathogenesis of ICI-related thyroid dysfunction is unclear, the early onset of thyrotoxicosis demonstrated by our study calls for careful monitoring, especially for particular races. [Table: see text]