High-dose treatment with stem cell support for CML

If your doctor thinks that a transplant is necessary or possible for you, they will discuss it with you in more detail. Stem cell transplants are generally only carried out in specialist cancer treatment centres. A stem cell transplant allows you to have much higher doses of chemotherapy| than usual. This can help to improve the chances of curing the leukaemia, or make a remission last longer.

Stem cells are blood cells at the very earliest stage of development in the bone marrow. They are mainly collected (harvested) from the blood, but can also be collected from the bone marrow. The stem cells can be donated by someone else (an allogeneic transplant|), or you can use your own stem cells (known as an autologous transplant).

The aim of this transplant is to give you a source of healthy bone marrow and to try to completely cure the leukaemia.

In an allogeneic transplant, stem cells are donated by someone else and given to you. The most suitable donor is usually a brother or a sister whose bone marrow is a close match to your own. Occasionally it’s possible to use bone marrow from someone who isn’t related to you, if tests have shown that their white blood cells are a good match with yours. The Anthony Nolan Trust| and British Bone Marrow Registry| both maintain registers of bone marrow donors in the UK.

In CML, an allogeneic transplant is usually carried out during the chronic phase|, when the disease is stable.

A transplant may be used after the blast phase has been treated and you are in remission but it wouldn’t usually be used as treatment for the blast phase.

High-dose treatment

The first stage of the treatment destroys your own bone marrow completely. This is done with high doses of chemotherapy, sometimes combined with radiotherapy| (high-energy rays).  After this treatment the donated stem cells are given to you through a drip into your central line.

The new stem cells, known as the graft, take a few weeks to settle in your bone marrow and start making the blood cells you need. Because you’re very vulnerable to infections during this time, certain precautions will be taken to protect you until your white cell count has recovered. You’ll be looked after in a room on your own and may be given antibiotics to help to prevent infections.

The hospital or specialist centre where you are treated will have its own policies on how to care for you during this time and your doctor or nurse will discuss this with you beforehand.

Graft versus host disease

Your doctors and nurses will watch you carefully during the transplant and for some months afterwards, for any signs of the new marrow reacting against your own body tissue (this is called graft versus host disease| – GvHD). This can occur at any time after your transplant. It doesn’t mean that your transplant hasn’t worked but it can cause various problems including diarrhoea, rashes and liver damage. Your doctor will prescribe drugs to help prevent the graft reacting to your body.

White blood cells from your donor (donor lymphocyte infusion)

After an allogeneic transplant, your doctors will monitor your blood closely for leukaemia cells. Having a small number of remaining leukaemia cells may be one of the reasons why CML comes back in some people after an allogeneic transplant.

One way of getting rid of these leukaemia cells is to have treatment with a type of white blood cell called lymphocytes taken from your donor. The lymphocytes help your immune system to reject the remaining leukaemic cells (known as the graft versus leukaemia effect – GvL). They can be collected from your donor especially for this reason, or they may be taken and stored when the stem cells are originally collected.

The lymphocytes are given through a drip into one of your veins (intravenously). This can be done in the outpatient department. Some people may need to have it done up to three or four times. Sometimes having a donor lymphocyte infusion can cause you to develop graft versus host disease.

Using your own stem cells

Collecting the stem cells

The stem cells are taken while you are free of any signs of the disease (in remission). A substance called G-CSF| will be given to you as an injection after a course of chemotherapy. G-CSF stimulates the stem cells to spill over from the bone marrow into the blood so that they can be collected from your blood.

High-dose treatment and recovery

You’re given very high doses of chemotherapy, with or without radiotherapy| (high-energy rays). Your own stem cells are then given back to you to ‘rescue’ you from the effects of the high-dose treatment and give you a source of healthy stem cells.