Immunotherapy uses the body’s immune system to fight cancer, offering hope where traditional treatments may fall short. According to the National Cancer Institute (NCI) and Mayo Clinic, immunotherapy has transformed cancer care. However, because it boosts the immune system, it can also cause side effects ranging from mild to life-threatening. Understanding the risks helps patients and caregivers make informed decisions.

Immunotherapy can overstimulate the immune system, causing it to attack healthy tissues. This may lead to inflammation in organs like the lungs (pneumonitis), liver (hepatitis), or intestines (colitis).

2. Flu-Like Symptoms

Many patients report fever, chills, fatigue, muscle aches, and nausea. These symptoms are often temporary but can interfere with daily life.

3. Skin Reactions

Rashes, itching, and sensitivity are common, especially with checkpoint inhibitors. In rare cases, severe skin conditions like Stevens-Johnson syndrome may occur.

4. Endocrine System Problems

Immunotherapy can disrupt hormone-producing glands, causing thyroid, adrenal, or pituitary issues. Patients may develop hypothyroidism, hyperthyroidism, or diabetes.

5. Risk of Severe Infections

Because immunotherapy alters the immune system, it may leave patients more vulnerable to infections, especially if combined with other treatments like chemotherapy.

6. Rare but Serious Reactions

Some patients may experience severe or even fatal reactions such as myocarditis (heart inflammation), neurological effects, or life-threatening allergic responses. These are uncommon but require immediate medical attention.

Key Takeaway

Immunotherapy offers new hope for many cancer patients, but it comes with risks. Patients should discuss potential side effects with their oncologist, weigh benefits against risks, and report any new symptoms immediately for early management.