Can immune-checkpoint inhibitors cause thyroid dysfunction in lung cancer patients?
Yes, immune-checkpoint inhibitors (ICIs) can cause thyroid dysfunction in people with lung cancer. These drugs help the immune system attack cancer, but they can also make it attack healthy organs, including the thyroid. The thyroid is a small gland in the neck that controls how the body uses energy. When ICIs affect it, the result is called a thyroid immune-related adverse event, or thyroid irAE.
This is one of the more common endocrine (hormone gland) side effects of these drugs. Most cases are mild and treatable, but many people end up needing thyroid hormone replacement. Doctors watch for it with regular blood tests.
What the research says
A review of ICI side effects lists thyroid dysfunction among the main immune-related problems, alongside gut, liver, and skin effects 5. It notes that anti-PD-1 drugs (such as nivolumab and pembrolizumab) have a different side-effect pattern than ipilimumab, with fewer severe events, and that these drugs are used in lung cancer 5. A 2022 review explains the pattern: most cases are destructive thyroiditis (inflammation that damages the gland) or hypothyroidism (an underactive thyroid), while hyperthyroidism (an overactive thyroid, such as Graves' disease) is rare 6. Most patients who develop these problems later need thyroid hormone replacement 6.
A meta-analysis of 10 randomized trials with 6,154 non-small cell lung cancer patients found that ICIs raised the risk of thyroid side effects compared with chemotherapy. The risk was about 7 times higher for hypothyroidism, about 5 times higher for hyperthyroidism, and about 6.5 times higher for thyroiditis 7.
A single-center study of 420 lung cancer patients treated with ICIs found that 69 (16.4%) developed thyroid irAEs 4. Most appeared in the first 6 months, and most were mild (grade 1 or 2), with only 1.4% severe 4. Thyroid replacement therapy was needed in 65.2%, and steroids were used in 13% 4. Male sex was linked to a lower risk, and one type of non-small cell lung cancer histology was linked to a higher risk 4.
The 2022 review adds two useful points: thyroid irAE development has been linked to longer survival in non-small cell lung cancer, and people with positive anti-thyroid antibodies before treatment have a higher incidence, suggesting these antibodies may help predict who is at risk 6.
What to ask your doctor
- How often will my thyroid (TSH and free thyroid hormone) be checked while I am on an immune-checkpoint inhibitor?
- What symptoms of an underactive or overactive thyroid should I watch for, and when should I call you?
- I had thyroid antibodies or a thyroid problem before treatment. Does that change my risk or my monitoring plan?
- If my thyroid is affected, will I need thyroid hormone replacement, and how will we track whether it is working?
- Could a thyroid side effect affect my cancer treatment plan, and how do we balance the two?
This question is drawn from common patient questions about Oncology and answered using cited medical research. We do not provide individualized advice.