Conditioning treatment before a donor stem cell transplant
Before a donor stem cell transplant, you will be given treatment so that the donor stem cells can grow in your bone marrow and make new blood cells. This is called the conditioning treatment.
The conditioning treatment usually means having a number of different chemotherapy drugs. There are different combinations of drugs used and different timings of when drugs are given.
Some people may also have radiotherapy to the whole body, which is known as total body irradiation, or TBI.
The conditioning treatment is given:
to prepare your immune system to accept the donor stem cells
to reduce the risk of your immune system rejecting and destroying the donor stem cells
sometimes to remove any remaining cancer cells from your body.
The conditioning treatment usually starts before the donor’s stem cells are collected. This is to make sure you’re ready for the transplant on the same day or soon after the stem cells are available.
Conditioning treatment usually lasts a few days. You’ll be given drugs to help control side effects, such as sickness. These drugs may make you feel sleepy.
There are different ways of giving conditioning treatment and also different levels of intensity (strength) of treatment. The treatment you have will depend on the type of cancer or leukaemia you have, your general health and any chemotherapy or radiotherapy treatment you’ve had in the past.
Full intensity conditioning
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High-dose chemotherapy, sometimes in combination with total body radiotherapy, is given to destroy your bone marrow and immune system. You are then given donor stem cells to replace your immune system and to act against any remaining cancer cells in your body.
Reduced intensity conditioning
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This type of transplant uses less intense doses of chemotherapy and sometimes radiotherapy, which means it has fewer complications. Reduced intensity conditioning weakens your immune system enough to allow the donor stem cells to grow in your bone marrow. The donor stem cells will gradually replace your immune system and act against any remaining cancer cells in your body.
While you’re in hospital, you’ll 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 soft, plastic tube (central line) can be put into a vein in your chest. Different types of central lines are available including Hickman® lines or Groshong® lines.
A central line can be used to:
give drugs and fluids
give the stem cells
collect blood samples.
The tube is inserted under a general or local anaesthetic. Usually a small cut (incision) is made in the skin over your chest, and the flexible plastic tube is placed under your skin and into a large vein in your chest. The other end of the tube stays outside your body and has a screw cap at the end, to which a drip or syringe can be attached.
The area may feel sore for a couple of days after the line has been put in, 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.
Sometimes an implantable port may be used instead. This 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.
Chemotherapy is the use of anti-cancer (cytotoxic) drugs to destroy cancer cells. In donor stem cell transplants, it is also used to destroy or weaken your immune system so that the donor stem cells can grow in your bone marrow. You’ll probably already have had some chemotherapy as part of your original treatment, so you may have some idea of what to expect.
The chemotherapy is given through your central line or implantable port, together with plenty of fluids. The treatment is usually given over several days and often involves a combination of different chemotherapy drugs.
Radiotherapy is the use of high-energy rays to destroy cancer cells. You may be given total body irradiation (TBI) as part of the high-dose treatment for some types of cancer.
If you’re going to have radiotherapy as well as chemotherapy, you’ll probably go to the radiotherapy department 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 ask any questions you may have.
Total body irradiation may be given twice a day for 6-8 sessions over 3-4 days. Each session lasts about 40 minutes. You can bring some CDs in with you to listen to during your treatment. If you’re having radiotherapy as part of a reduced intensity regimen, only one or two low doses of TBI may be needed.
Before each session, the radiographer will position you carefully and will make sure you’re comfortable. You’ll have to change position a few times during the session, and the radiographer will explain this to you. During the treatment you’ll be left alone in the room, but you’ll be able to talk to the radiographer, who will be watching you from the next room. Radiotherapy isn’t painful, but you do have to keep still while your treatment is being given.
Many people find that they don’t have many side effects from total body irradiation. This is because the treatment only gives a relatively low dose of radiation to any one part of the body. Common side effects are tiredness, feeling sick (nausea), diarrhoea and a sore mouth.