What are the side effects of immunotherapy?

Immunotherapy is a treatment used for some children with high-risk neuroblastoma. It helps the body’s immune system recognise and attack cancer cells. Like all treatments, immunotherapy can cause side effects, but not all children experience the same effects, and many are manageable with the right support. 

Your child’s healthcare team will monitor them closely throughout treatment and help manage any side effects that occur. 

Common short‑term side effects 

Short‑term side effects usually happen during immunotherapy or shortly afterwards. These may include: 

• Pain: this may occur at the treatment site or elsewhere in the body. Medication to manage pain may be given to address this. 

• Fever: this is common during immunotherapy. 

• Tiredness and feeling unwell: children often feel very tired and generally unwell during and after treatment. Rest and gentle activities can help. 

• Loss of appetite: some children may need additional nutritional support, such as a nasogastric (NG) tube, if they are unable to eat enough 

• Nausea and vomiting or diarrhoea: these are common but can usually be managed with medicines. 

• Low blood pressure: this can sometimes occur during treatment. 

Other possible side effects 

Some children may experience additional side effects, including: 

• Nerve‑related symptoms, such as numbness, tingling or weakness in the hands or feet (known as peripheral neuropathy). 

• Allergic‑type reactions, including a rash, itching, swelling or breathing difficulties. 

• Occasional changes in liver or kidney function, which are monitored through routine blood tests. 

Rare but serious side effects 

A small number of children may develop more serious side effects during immunotherapy. 

Capillary leak syndrome 

This is a rare but serious condition where fluid leaks from small blood vessels into surrounding tissues, which can cause swelling and low blood pressure. Children receiving immunotherapy are monitored closely so that this can be identified and treated quickly if it occurs. 

Managing side effects and ongoing support 

Side effects vary in severity and duration. Many can be managed with medicines, dietary changes, rest, or adjustments to treatment. Your child’s medical team will explain what to look out for and how side effects are treated. 

If you notice anything unusual or are worried about your child at any point, you should contact your child’s doctor or nurse for advice.