Side Effects

Although using immunotherapy typically results in fewer side effects that can be less severe than those associated with other forms of cancer treatment, some side effects still can occur, and some may be serious. Not everyone will experience the same side effects with immunotherapy, and some people may not experience any at all. Symptoms can vary in severity and differ according to the type of immunotherapy.

Some common side effects associated with immunotherapy are discussed here.

  • Immune-mediated adverse reactions are not common but can occur with certain immunotherapies. This type of reaction occurs when the immune system is overstimulated by the treatment and may cause inflammation, swelling or redness, which may be painful. Following are some of the systems affected by immune-mediated adverse reactions and common symptoms:
    • Endocrine (endocrinopathies): hyperthyroidism, hypothyroidism, extreme fatigue, persistent or unusual headaches
    • Gastrointestinal (colitis): diarrhea with or without bleeding, abdominal pain, bowel perforation
    • Neurologic (neuropathies): numbness or tingling, sensory overload or sensory
    • Pulmonary (pneumonitis): chest pain, shortness of breath
    • Renal (kidneys) (nephritis): Decrease in urine output, blood in urine, swelling in ankles, loss of appetite
    • Skin (dermatitis): Rash, skin changes

Since immunotherapy works differently than other cancer treatments, partnering with your doctor to monitor for complications is vital. To determine what is normal for you, your doctor likely will perform baseline assessments for monitoring purposes throughout treatment. You will play a key role in detecting what is abnormal for you and communicating that to your doctor immediately, so it is important to understand how to recognize an immune-mediated adverse reaction, as some may not produce obvious symptoms.

Having the appropriate contact information handy is important. Before beginning immunotherapy, ask your health care team whom to call, day or night, if you think you may be having an immune-adverse mediated reaction. It is necessary to call that person immediately to avoid any life-threatening complications. Without treatment, an autoimmune response can be irreversible or even deadly. For the majority of reactions, early intervention can be reversed with steroids and by temporarily stopping immunotherapy.

These types of side effects can be delayed, sometimes occurring weeks or even months after treatment stops. Work with your doctor to determine a plan for how long to be vigilant about potential side effect symptoms.

  • Fatigue is the most common side effect reported in multiple immunotherapies, including checkpoint inhibitors, cytokines and oncolytic virus therapy. Fatigue associated with cancer is different than simply feeling tired and may cause you to feel physically, emotionally or mentally exhausted.
  • Flu-like symptoms, such as fever, chills, aches, headache, drowsiness, nausea, vomiting and loss of appetite, can occur with cytokines or oncolytic virus therapy.
  • Diarrhea is common with checkpoint inhibitors and can vary in severity and duration. Diarrhea can lead to severe dehydration and electrolyte imbalance, but also could be a symptom that your immune system is going into overdrive. Call your health care team if you experience symptoms that interfere with your daily activities, such as severe abdominal cramping, or that cause you to fear leaving your home.
  • Mild skin reactions, such as bumpy or itchy red rashes, can occur. These reactions can be common with checkpoint inhibitors. Other skin problems include yellowing or changes in skin color, blistering, hives, pale patches and flushing or redness. Although rarely severe, these symptoms can be uncomfortable. Your doctor may recommend a corticosteroid or numbing medicine, an antihistamine, medicated creams or antibiotics.
  • Depression can affect your mood, behavior and ability to think and concentrate, as well as be associated with fatigue, appetite loss, difficulty falling asleep or extreme tiredness. Depression can include suicidal thoughts or other psychiatric disorders. Call your doctor’s office if you notice these types of mood changes.

Frequent communication with your health care team is important for monitoring your symptoms. Seek treatment immediately, regardless of time of day, for any medical emergencies, including high fever, inflammation, swelling, severe abdominal pain or shortness of breath.

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