5 Lung Cancer Immunotherapy Side Effects and How to Manage Them

Immunotherapy has become one of the most widely used treatments for lung cancer, and during Lung Cancer Awareness Month it is worth knowing how its side effects work. Drugs such as Keytruda (pembrolizumab), Opdivo (nivolumab), Tecentriq (atezolizumab), Imfinzi (durvalumab) and Libtayo (cemiplimab) are checkpoint inhibitors. They release a natural brake on the immune system so it can recognize and attack cancer.

The trade-off is that a revved-up immune system sometimes inflames healthy organs. Doctors call these immune-related adverse events. They can start weeks or months into treatment, and occasionally after treatment ends, so it helps to know the signs. The guidance below reflects the joint ASCO and NCCN guideline that cancer centers use to manage these side effects.

1. Skin Rash and Itching Are the Most Common

Skin problems are the side effect patients notice most often, reported in up to about 7 in 10 people on checkpoint inhibitors in studies summarized by the guideline. Most cases are a mild rash or itching that responds to moisturizers, steroid creams and anti-itch medicine, and treatment usually continues.

Call your team right away if the rash spreads quickly, blisters, peels or involves your mouth or eyes. Those signs are rare but need same-day attention.

2. Diarrhea Can Signal Colitis

Colitis means inflammation of the colon, and it affects roughly 8% to 27% of patients, depending on the drug or combination. It often starts as more frequent or looser stools than usual, sometimes with belly cramps, mucus or blood.

Unlike diarrhea from chemotherapy, this kind is driven by the immune system, so over-the-counter diarrhea medicine alone may hide the problem without treating it. Let your team know about any change in bowel habits. Mild cases are watched closely; moderate or severe ones are treated with steroids, which calm the immune response, and immunotherapy is paused until things settle.

3. Thyroid Changes Often Need Only a Daily Pill

Immunotherapy can inflame the thyroid, the gland in your neck that controls energy and metabolism. The most common result is an underactive thyroid, called hypothyroidism, which can cause tiredness, weight gain, feeling cold or constipation. Some people first have a brief overactive phase with a racing heart or jitteriness.

Your team checks thyroid levels with routine blood tests. If the gland slows down, a daily thyroid hormone pill replaces what it no longer makes. Hormone-related side effects like this are managed with replacement hormones rather than by stopping immunotherapy for good, so many people keep getting their cancer treatment. The pill is often needed long term.

4. A New Cough Can Signal Lung Inflammation

Pneumonitis is inflammation of the lungs, and it matters especially for people with lung cancer because its signs, a new or worsening cough, shortness of breath or chest pain, can look like the cancer itself or an infection. That overlap is exactly why you should report breathing changes instead of waiting.

Your team may order a chest scan to sort out the cause. If it is pneumonitis, immunotherapy is held and steroids are started, with the dose depending on how severe it is. Most people improve with treatment.

5. Liver Inflammation Usually Shows Up in Blood Work

Hepatitis from immunotherapy means the immune system is inflaming the liver. It is found in about 2% to 10% of people on a single checkpoint inhibitor and up to 30% on combinations such as Opdivo plus Yervoy (ipilimumab). It often causes no symptoms and is caught on routine liver blood tests, which is one reason those lab draws before each infusion matter. Yellowing of the skin or eyes, dark urine or pain under the right ribs should be reported right away.

Treatment again depends on severity, from closer monitoring to pausing immunotherapy and starting steroids.

About Steroids, and Why Speaking Up Pays Off

Steroids such as prednisone are the main tool for calming these side effects. The guideline advises using the lowest dose that works for the shortest time, then tapering slowly over about four to six weeks rather than stopping suddenly, which can let symptoms flare back.

Many patients worry that reporting a problem will cost them their treatment. As one nurse practitioner told CURE, "just because you report side effects does not mean that we are going to have to change" therapy (read more). Catching side effects early usually keeps them milder and easier to treat. It also helps to carry a card or phone note saying you are on immunotherapy, so an emergency room doctor knows to consider these effects. For more on what guides lung cancer treatment choices, see CURE's lung cancer biomarker Q&A.

References

1. Schneider BJ, et al. "Management of Immune-Related Adverse Events in Patients Treated With Immune Checkpoint Inhibitor Therapy: ASCO Guideline Update." Journal of Clinical Oncology. 2021.
2. "Management of the 10 Most Common Immune-Related Adverse Events With Immune Checkpoint Inhibitors" (ASCO guideline highlights). JCO Oncology Practice. January 2022.

For more news on cancer updates, research and education, don't forget to subscribe to CURE®'s newsletters here.