(117) Evaluation of Thyroid Toxicity Management Associated with Checkpoint Inhibitor Use

Poster Abstract: Background/rationale:
Immunotherapy has been shown to provide a varying incidence of thyroid issues in patients. While hypo and hyperthyroidism can both occur, hypothyroidism is more common. A recent meta-analysis estimated a hypothyroidism incidence of around 7% for patients receiving PD1-inhibitors monotherapy. When PD1-inhibitors are used in combination with CTLA-4 inhibitors, the risk of hypothyroidism increases further to around 13.2%. Symptoms of hypothyroidism can be easy to miss, but they can be easily reversed through levothyroxine replacement. To optimize treatment and ensure patients are being treated in a timely manner, this project seeks to evaluate current practice in thyroid toxicity management related to immunotherapy.

Objective(s):
The purpose of this study is to evaluate the treatment patters and corresponding responses of checkpoint inhibitor-induced thyroid toxicity within an ambulatory oncology clinic.

Methods:
To identify a study population, investigators cross-referenced a list of patients who received/are receiving immunotherapy at Avera Cancer Institute and a list of patients with levothyroxine prescribed for home use. Retrospective chart review was then completed to collect the immunotherapy regimen, levothyroxine initiation date, TSH at time of levothyroxine initiation, levothyroxine dose, specialty who managed the thyroid toxicity, and how long to achieve goal TSH and T4.

Results:
Results pending

Discussion/conclusion:
Pending based on results

References (must also be included in final poster): El Sabbagh R, Azar NS, Eid AA, Azar ST. Thyroid Dysfunctions Due to Immune Checkpoint Inhibitors: A Review. Int J Gen Med. 2020;13:1003-1009. Published 2020 Nov 4.