Considerations for Use of Immune Checkpoint Inhibitors in Cancer Therapy for Patients with Co-Existing Thyroid Eye Disease.

Immune checkpoint inhibitors (ICIs) have revolutionised the field of oncology. While most ICIs are well-tolerated, severe and fatal immune-related adverse events (irAEs) have been documented, likely related to the strengthened immunity harnessed by ICIs against tumours. Endocrinopathies are some of the most common irAEs, with both hypothyroidism and hyperthyroidism encountered after ICI use. As such, patients with pre-existing autoimmune conditions, such as Graves' disease (GD) with clinically active thyroid eye disease (TED), are excluded from most clinical trials studying ICIs due to concerns of exacerbating pre-existing autoimmune conditions or of increasing the potential for irAE development. The limited information currently available on the safety and efficacy of ICIs in this population poses a clinical challenge for oncologists. The objective of this commentary is to highlight these challenges and provide treatment recommendations pertaining to two specific cohorts of patients with GD, namely GD patients with minimal eye complications and GD patients with previous TED who underwent radiotherapy, surgery or pulse methylprednisolone and whose disease is now quiescent, and to patients with subclinical autoimmune thyroid disease.