What is immunotherapy induced colitis?

Immunotherapy is a treatment for cancer that helps the immune system recognise, target, and eliminate cancer cells wherever they are in the body. Many cancers employ methods to hide themselves from the body’s immune cells. Immunotherapy blocks these evasion strategies, so the body’s immune system can recognise and kill the cancer cells. 

In some people, immunotherapy can also cause the immune system to attack normal tissues within the body, causing inflammation. When this inflammation occurs in the large bowel, this condition is called colitis.

Symptoms of colitis

Symptoms of colitis include:

  • Diarrhoea.
  • Abdominal pain.
  • Weight loss.
  • Sometimes fever and vomiting.

Your medical team will have ruled out other causes for your bowel symptoms, such as infection. You are likely to need a camera test to look at your bowel, called an endoscopy, and take some biopsies. A biopsy is a small sample of the bowel which is then analysed for signs of inflammation.

More severe symptoms of colitis may mean your immunotherapy will need to be put on hold.

How do we treat immunotherapy related colitis?

There are several different treatments for immunotherapy related colitis depending on how severe your symptoms are.

Medications which reduce inflammation within the bowels are used. These include steroids, also known as corticosteroids, such as prednisolone. Steroids work by suppressing the immune system to stop it from attacking your good cells and hopefully improve your symptoms.

How long will I have to take steroids?

Everyone is different and each person’s body responds differently. You will be monitored closely when you are on steroids to check they are working to reduce your symptoms.

Taking steroid tablets for less than three weeks is unlikely to cause any significant side effects. However, you may get some side effects if you need to take them for longer or at a high dose. Often, patients experience no side effects from steroids.

Side effects of steroid tablets can include:

  • Indigestion or heartburn.
  • Increased appetite, which could lead to weight gain when used long term.
  • Difficulty sleeping.
  • Changes in mood and behaviour, such as feeling irritable or anxious.
  • An increased risk of infections – especially chickenpox, shingles, and measles
  • High blood sugars or diabetes.
  • Weakening of the bones (osteoporosis).
  • High blood pressure.
  • Cushing's syndrome – which can cause symptoms such as thin skin that bruises. easily, a build-up of fat on the neck and shoulders and a red, puffy, rounded face.
  • Eye conditions, such as glaucoma and cataracts.
  • Mental health problems, such as depression or suicidal thoughts.

Most side effects will pass once treatment stops. Tell your doctor or nurse if you notice any new symptoms. If possible, you should take your steroids in the morning to reduce trouble sleeping.

You will be given a tablet to take alongside your steroids to protect your stomach from irritation and it is also recommended to take your steroid tablets with food.

If you are on steroids for more than three weeks, your doctor or specialist nurse might prescribe a bone strengthening drug to prevent the weakening of your bones and a low dose of antibiotics to prevent you from getting an infection.

Infliximab treatment for colitis

If your symptoms do not improve on steroids, we sometimes use another drug called Infliximab to treat colitis.

Infliximab belongs to a class of medicines called ‘biologics’. These are therapies that are used commonly in inflammatory bowel conditions such as Crohn’s disease and ulcerative colitis. They also work in colitis caused by immunotherapy. There is no evidence that infliximab stops the anti-cancer effect of the immunotherapy.

Before having infliximab

Before infliximab can be given, the following checks will be carried out to make sure that it is safe for you to receive the medication:

  • Medical history check, including symptoms of infection, current medication, and allergies.
  • Vaccination history.
  • History of chickenpox and shingles, including any recent exposure.
  • Weight (used to calculate the dose).
  • Screen for tuberculosis.
  • Screen for hepatitis.
  • Screen for HIV.
  • Pregnancy test (if applicable).

How is infliximab given?

Infliximab is given in hospital via a drip directly into the vein over one to two hours. Following this, you must remain in hospital for a short time in case you experience a side effect to the medicine. Generally, Infliximab is well tolerated with minimal side effects. Around 1 in every 10 people taking infliximab may have:

  • Infusion or injection site related reactions (redness, swelling or pain where you’ve injected).
  • Upper respiratory tract infections (like colds, tonsillitis, and sinus infections) or flu
  • Tummy pain or feeling sick (nausea).
  • Headaches.

Patients usually require three doses which are given at zero, two and six weeks apart. You may require more doses in the future if your symptoms persist. In most cases, Infliximab will resolve your symptoms.