Thyroid Dysfunctions Due to Immune Checkpoint Inhibitors: A Review

Rawaa El Sabbagh,¹ Nadim S Azar,^2,3 Assaad A Eid,³ Sami T Azar<sup>1

1</sup>Division of Endocrinology and Metabolism, American University of Beirut, Beirut, Lebanon; ²Department of Internal Medicine, American University of Beirut, Beirut, Lebanon; ³Department of Anatomy, Cell Biology and Physiological Sciences, American University of Beirut, Beirut, Lebanon

Correspondence: Sami T Azar
Division of Endocrinology and Metabolism, American University of Beirut Medical Center, Beirut, Lebanon
Email sazar@aub.edu.lb

Aim: Immune checkpoint inhibitors are anti-cancer drugs associated with adverse events that result from releasing the immune system against self-antigens while attacking cancer cells. Thyroid dysfunctions are among the most common associated adverse events.
Materials and Methods: We conducted a systematic search of the literature in 2 databases: PubMed and Medline. Articles that reported thyroid adverse events of immune checkpoint inhibitors were reviewed. Thyroid disorders include hyperthyroidism and hypothyroidism and are most commonly seen with programmed cell death protein 1 and programmed death-ligand 1 inhibitors.
Conclusions: Thyroid disorders are common side effects seen with check point inhibitors and are treated, depending on the clinical situation, by adequate hormonal replacement, thionamides, corticosteroids or observation only. The use of high dose corticosteroids has not been established as a treatment of thyroid toxicities. Thyroid function tests screening should be a part of baseline laboratory testing of all patients undergoing treatment with immune checkpoint inhibitors.

Keywords: immune check point inhibitors, thyroid dysfunction, anti-PD1, anti-PDL1