Immune Checkpoint Inhibitors (ICI): Endocrine related side effects
Immune checkpoint inhibitors (ICIs) are a type of treatment used to help our immune system identify and destroy cancer cells. Because of the way that Immune Checkpoint Inhibitors (ICIs) work, they can result in unique side effects called immune-related adverse events (IrAEs). Immune related side effects result from the immune system attacking cells that are not cancer. IrAEs can often resemble autoimmune disorders and can affect any organ in the body.
What is the endocrine system?
The endocrine system is a set of organs that helps control the hormones in your body. These hormones are a vital part in regulating many important functions such as metabolism, reproduction, mood, and more. Although endocrine disorders can be an uncommon side effect of immune checkpoint inhibitors, it is still important to be aware of the symptoms so that you can communicate this with your provider.
Below is a table of potential endocrine conditions and their corresponding symptoms.
Immune related condition | Area effected | Symptoms | Tests to diagnose |
Hypothyroidism (Low thyroid hormone levels) | Thyroid | Fatigue Weight gain Slowed heart rate Trouble tolerating cold Joint/Muscle pain Depression | Thyroid Stimulating Hormone (TSH) Thyroxine (T4) |
Hyperthyroidism (High thyroid hormone levels) | Thyroid | Warmth and/or sweating Anxiety Weight loss Tremors Increased heart rate or palpitations Increased bowel movement frequency Shortness of breath Goiter | Thyroid Stimulating Hormone (TSH) Thyroxine (T4) |
Hypophysitis (Inflammation of the pituitary gland) | Pituitary Gland | Fatigue Headache Cold intolerance Excessive thirst Excessive urination Weight loss Electrolyte imbalance
| Adrenocorticotropic Hormone (ACTH) Thyroid Stimulating Hormone (TSH) Follicle Stimulating Hormone (FSH) Luteinizing hormone (LH) Growth Hormone (GH) Prolactin Brain MRI (to identify swelling of pituitary gland) |
Adrenal Insufficiency or Adrenal Crisis (This is a medical emergency) | Adrenal Gland | Dehydration Nausea/Vomiting Fatigue Confusion Weakness Abdominal pain Low blood pressure Weight loss | Complete Metabolic Panel (CMP) Serum Cortisol Corticotropin (ACTH) Aldosterone Renin |
Type 1 Diabetes | Pancreas | Excessive thirst Frequent urination Weight loss Confusion Lethargy Rapid breathing Nausea/Vomiting Abdominal pain | Blood sugar levels Urine tests to check for sugar and protein Labs to check electrolytes and kidney function |
How are these side effects managed?
Treatment of endocrine disorders, such as those described above, can vary depending on the severity of your symptoms and lab results. Potential management options include:
Replacement of the hormone that is low (such as thyroid hormone, insulin, or mineralocorticoids)
Referral to an endocrinologist (a physician who specializes in the endocrine system) to help diagnose and manage these side effects
Delays in treatment
Discontinuation of current treatment regimen
Always communicate any new or changing symptoms with your provider. If you are seeing a provider outside of your usual care team, be sure to tell them that you are on immunotherapy. It may also be a good idea to keep a list of your current treatment, as well as your oncologist’s name, and contact information either in your wallet or on your phone.
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