High-dose treatment (sometimes called the conditioning regimen) is given to destroy any remaining cancer cells in your body.

When you are having your own stem cells, the treatment may be given at any time from one day to a few weeks after the stem cells or marrow have been collected.

When you are having an allogeneic transplant you will usually be given your donor’s stem cells within a day of finishing your treatment. The donor will have their stem cells collected within 24 hours of you finishing your high-dose treatment.

While you are in hospital, you will need to have regular doses of medicines and many blood tests, over several weeks. To make this easier, and to prevent you from having frequent injections, a plastic tube (called a central line) can be put into a vein in your chest. The tube is put in under a general or local anaesthetic. Usually a small cut (incision) will be made in the skin over your chest, and a narrow flexible plastic tube will be placed under your skin and into a large vein in your neck. The other end of the tube stays outside your body and has a screw cap at the end. The tube can be used to:

• give drugs and fluids
• give the stem cells or bone marrow
• collect blood samples.

After the line has been put in, the area may feel sore for a couple of days, but it should then be painless. The line can stay in for months and the nurses will show you how to look after it to help prevent blockages or infections.

Instead of a central line, a PICC line (peripherally inserted central venous catheter) or an implantable port may be used. A PICC line is a long, thin tube put into a vein in the crook of your arm. The doctor or chemotherapy nurse will explain the procedure to you. You will be given a local anaesthetic before the line is put in. An implantable port is a thin, soft plastic tube that is put into a vein in the chest and has an opening (port) just under the skin on your chest or arm.

The high-dose treatment usually lasts a few days (this varies from one hospital to another) and consists of high doses of chemotherapy. The chemotherapy is sometimes followed by radiotherapy to your whole body (known as total body irradiation, or TBI).

Chemotherapy is the use of anti-cancer (cytotoxic) drugs to destroy cancer cells. You will probably already have had some chemotherapy as part of your original treatment, and so may have some idea of what to expect.

Our section on chemotherapy, explains the treatment and has tips on how to cope with side effects.

The high-dose chemotherapy is given through your central line, PICC line or implantable port, together with plenty of fluids. The treatment is usually given over several days.

During this time, it will probably be suggested that you do not have many visitors. The high doses of chemotherapy drugs may make you feel sick. You will be given anti-sickness medicines (anti-emetics), which will reduce or stop you feeling sick.

The chemotherapy drugs will make your hair fall out. Your hair will grow back once the treatment is finished, but it may seem hard to bear at the time. You may find it helpful to read our section on coping with hair loss.

Radiotherapy uses high-energy rays to destroy cancer cells. You may be given radiotherapy to your whole body - known as total body irradiation (TBI) - as part of the high-dose treatment (or conditioning). Radiotherapy is used as part of the treatment for some types of cancer.

If you are to have radiotherapy as well as chemotherapy, you will probably go to the hospital for a planning session a few days before the treatment begins. The doctor will explain what will happen during your course of radiotherapy, and you can use this as a chance to ask questions.

The total body irradiation may be given twice daily over three days, in 6–8 sessions. Each session lasts about 40 minutes. The TBI can also be given in a single session over several hours.

Before each session the radiographer will position you carefully, standing, sitting or lying, and will make sure that you are comfortable. You will have to change position a few times during the session and the radiographer will explain this to you. During the treatment you will be left alone in the room, but you will be able to talk to the radiographer who will be watching you from the next room. Radiotherapy is not painful but you do have to keep still while your treatment is being given.

Many people find that they do not have many side effects from total body irradiation. This is because the treatment gives only a relatively low dose of radiation to any one part of the body. Common side effects are feeling sick (nausea), diarrhoea and a painful mouth.

If you still feel sick from the effects of the chemotherapy, you will probably be given an anti-sickness medicine before each session of radiotherapy, to make you more comfortable.