This information is about the use of interferon alpha as a treatment for people with cancer. This information describes interferon, how it is given and some of its possible side effects. It should ideally be read with our general information about your type of cancer.

Interferon is a protein that occurs naturally in the body in very small amounts. It can also be made as a drug. There are three main types: alpha, beta and gamma. This information describes interferon alpha.

Interferon is used as a treatment for some types of cancer. It is used to treat cancer of the kidney, malignant melanoma and carcinoid tumours. It is also sometimes used to treat certain types of lymphoma and leukaemia.

Interferon alpha is a white powder that forms a clear, straw-coloured liquid when mixed with water. It can also be supplied ready-diluted in small glass vials (bottles), pre-filled syringes and special injection-pen devices.

Interferon is given as an injection just under the skin (subcutaneously), usually in the thigh or abdomen. You or a relative can be taught how to give these injections, or a district nurse may visit you so that you can have your treatment at home. A variety of pre-filled syringes are available. It can be helpful to discuss the most suitable treatment with your doctor or nurse.

Your doctor or specialist nurse will explain how often you will be given the drug and how long the treatment course will last. This varies from person to person, depending on their illness.

Interferon is given to stimulate the body’s own immune system to fight some types of cancer. The exact way in which it works is not fully understood. It is thought to have a wide range of effects on the body. It may do one or more of the following:

• slow down or stop cancer cells dividing
• reduce the ability of cancer cells to protect themselves from the immune system
• strengthen the body’s immune system.

The amount of interferon that occurs naturally in the body is very small. When interferon injections are given, the amount in the body increases greatly. For this reason it causes side effects, even though it is a naturally occurring substance. The side effects of interferon are not usually severe, however. People react to drugs in different ways, so it is not possible to predict who is going to have side effects or which they will have. The most common side effects are listed below:

Flu-like symptoms These include a high temperature, chills and muscle and joint pains. They may start two to three hours after the drug is given, but they do not last long. Your doctor may prescribe medicine to reduce these side effects. After the first injection these symptoms may be quite severe, but they usually become much less of a problem with further injections. Some people find it helpful to have their interferon before going to bed at night so that the side effects are less noticeable.

Fatigue (a feeling of tiredness and having no energy) Fatigue can be a problem and sometimes it worsens over the course of injections. It is important to allow yourself plenty of time to rest. Tiredness can affect many aspects of your life.

Feeling sick (nausea), being sick (vomiting) and loss of appetite Feeling sick, vomiting and loss of appetite is rare. Your doctor can prescribe medicine to help.

Skin irritation may occur at the injection site This can be reduced by giving the injections in different places. Sometimes a more widespread rash can occur as a result of an allergic reaction.

Dizziness sometimes occurs It is important to report this to your doctor.

Depression and emotional changes Interferon can sometimes make people feel depressed. If you feel very low while you are taking it, let your doctor know, as help is available.

Pins and needles in the hands and toes Let your doctor know at your next appointment if this happens.

Hair loss Some people will find their hair falls out, but usually it will just thin. The effect is temporary and the hair will regrow once the treatment has finished.

Fertility Interferon may affect your ability to have children. In women it may affect the menstrual cycle and in men there may be a lowered sperm count. These effects may be temporary but for some people can be permanent.

Temporary reduction in the production of blood cells by the bone marrow This reduces the number of cells in the blood and can make you more vulnerable to infection, bleeding or bruising. It can also lead to anaemia (a lack of red blood cells). It is important to report any signs of bleeding, bruising or infection to your doctor. The bone marrow will return to normal when the treatment is stopped.

Effects on circulation Interferon may alter the rhythm of the heart or affect your blood pressure, but this will go back to normal when the drug is stopped.

The doctors and nurses looking after you will monitor you closely during your treatment. You will probably be asked to give regular samples of your blood and/or urine. They will also take your temperature, pulse and blood pressure. These tests help to monitor the effects of the interferon on your body. If you are having your injections at home, you may need to attend regular outpatient appointments at your hospital so that the tests can be carried out.

Interferon should be kept in a refrigerator Portable fridges can be bought from camping shops to store the interferon if you are away from home. There will be instructions about this in the patient information leaflet that you are given with your interferon.

This section has been compiled using information from a number of reliable sources including:

• Martindale: The Complete Drug Reference (35th edition). Sweetman et al. Pharmaceutical Press, 2007.
• British National Formulary (54th edition). British Medical Association and Royal Pharmaceutical Society of Great Britain, September 2007.

For further references, please see the general bibliography.