In 2003, at age 43, Laura Porter, MD, was in her second year of her residency in her medical training, when she was diagnosed with stage 4 colon cancer. She has had recurrences in her ovary, liver, pancreas, and abdominal lymph nodes. In May 2006, she became cancer-free. Since 2005, she has been a patient advocate and medical consultant in the field of colorectal cancer, sharing her survival experience and medical expertise. 

For the past 3 years, the American Society of Clinical Oncology (ASCO) has named some form of immunotherapy the Advance of the Year in its annual Clinical Cancer Advances report. This treatment approach has offered many successes in treating different types of cancers. Immunotherapy is exciting, but we also need to be aware of the risks of taking the brakes off the immune system.  

Immune checkpoints are proteins that act as brakes on the immune system. Immune checkpoint inhibitors, a type of immunotherapy, target these proteins. Blocking these checkpoints takes the brakes off the immune system and allows it to attack cancer cells. These treatments are at the center of important developments in the treatment of lung cancer, bladder cancer, melanoma, and other types of cancer.

We have seen and heard more and more stories about people with grim cancer diagnoses who became cancer-free after treatment with immunotherapy. This offers hope to those with cancer, but we need to be cautious when discussing immunotherapy. This treatment method is still new, and the cancer community is still learning about how it affects the body. An unfettered immune system may end up attacking healthy, functioning parts of a person’s body, causing unpredictable side effects that may be life-threatening if not treated early.

Realizing this, ASCO and the National Comprehensive Cancer Network (NCCN) collaborated to create guidelines to help patients, caregivers, and clinicians recognize, assess, and manage the possible side effects of immune checkpoint inhibitors. As a patient advocate, I served on this guideline panel.

Common side effects

These side effects are common but may not occur in all people or with all types of immunotherapies.

• Feeling tired (fatigue)

• Diarrhea

• Fever

• Shortness of breath

• Rash and/or blisters, covering less than 10% of the body

• Nausea

• Vomiting

• Itching

• Headache

• Weight loss

• Difficulty falling or staying asleep

• Decreased appetite

Dangerous side effects

Severe side effects can be life threatening. They may occur right away or up to 2 years after treatment ends.

If you are treated with an immune checkpoint inhibitor, it is important that you are aware of these side effects and that you call your doctor right away if they occur. If caught early, they can be treated. The list below describes dangerous side effects and their symptoms.

• Side effect: Inflammation of the lung (pneumonitis)

  • New or worsening cough

  • Shortness of breath

  • Chest pain

• Side effect: Inflammation of the liver (hepatitis)

  • Yellowing of skin (jaundice)

  • Severe nausea or vomiting

  • Pain on the right side of your stomach area

  • Drowsiness

  • Tea-colored urine

  • Bleeding or bruising

  • Feeling less hungry than usual

• Side effect: Inflammation of the colon (colitis)

  • Diarrhea (loose stools) or more bowel movements than normal

  • Blood in stools or black, tarry, or sticky stools

  • Severe abdominal pain or tenderness                    

• Side effect: Hormone or gland problems, especially the thyroid, pituitary, and adrenal glands and the pancreas

  • Headaches that will not go away

  • Extreme tiredness

  • Weight gain or weight loss

  • Dizziness or fainting

  • Changes in mood or behavior, such as decreased sex drive, irritability, or forgetfulness

  • Hair loss

  • Feeling cold

  • Constipation

  • Voice getting deeper

  • Excessive thirst or increased urination

• Side effect: Inflammation of the brain (neuropathy, meningitis, or encephalitis)

  • Headache

  • Fever

  • Tiredness or weakness

  • Confusion

  • Memory problems

  • Sleepiness

  • Hallucinations (seeing or hearing things that are not there)

  • Severe muscle weakness

  • Numbness or tingling in your hands or feet

  • Extreme sensitivity to light

  • Neck stiffness

• Side effect: Kidney problems, including kidney failure

  • Change in the color or amount of urine

  • Blood in the urine

  • Swelling in the ankles

  • Loss of appetite

• Side effect: Complicated skin reactions

  • Rash that affects your quality of life

  • Blisters covering over 30% of the body

  • Itching

  • Ulcers in the mouth, nose, ears, or other mucous membranes, making it difficult to eat or drink

• Side effect: Severe infections

  • Fever

  • Cough

  • Flu-like symptoms

  • Pain when urinating

• Side effect: Eye problems (may indicate a more widespread problem)

  • Blurry vision, double vision, or other vision problems

  • Eye pain or redness

• Side effect: Severe infusion reactions

  • Chills or shaking

  • Itching or rash

  • Flushing

  • Shortness of breath or wheezing

  • Swelling of face or lips

  • Dizziness

  • Fever

  • Feeling like passing out

  • Back or neck pain

Immunotherapy is exciting because of the promise it offers. It is becoming an available treatment option in many different types of cancer, bringing hope to more and more patients. Research is being done to help identify those for whom immunotherapy may work and those who may have severe side effects. Until then, however, it is important that patients, caregivers, and clinicians know what to look for and to have an established response plan if a side effect develops. If you receive immunotherapy, it is important to be aware of the possible side effects and to seek immediate help at the first sign of a problem.

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