Conditioning therapy

What is conditioning therapy?

When you get conditioning therapy for a stem cell transplant, it means you’ll need to spend some time in hospital before your transplant. For most people, this process should last around a week.

Conditioning therapy might involve either one, or a combination of,these types of different treatments:

Chemotherapy

You could get chemotherapy in a tablet form, but will most likely get it as a liquid through your central venous catheter (CVC). You will often hear this called your ‘central line’.

Radiotherapy

A radiographer will give you this treatment at hospital. It uses radiation to remove any abnormal cells that are causing your condition, while also preparing your bone marrow to receive your new stem cells.

Are there different types of conditioning therapy?

There are two different types of conditioning therapy:

• Full intensity, which you might also hear called ‘myeloablative’.
• Reduced intensity conditioning (RIC).

Your consultant will look at many factors when deciding the best type of conditioning therapy for you. They might consider your age, general health and the type of blood cancer or blood disorder you have.

Full intensity conditioning

Full intensity conditioning is strong enough to remove all your existing blood stem cells. Following this, your donor’s stem cells need to be added to your blood as soon as treatment has finished – they need to start rebuilding your immune system right away.

Hospitals often use this type more with younger people, and usually if you have an autologous transplant. Generally, if your consultant feels you’re well enough to cope with the potential side effects, they might decide full intensity is best for you.

Two of the most commonly used chemotherapy medications for full intensity conditioning are:

• Cyclophosphamide
• Busulfan

However, as experts are constantly developing new treatments, you may hear your transplant team talking about other types of medication too.

Reduced intensity conditioning (RIC)

If doctors don’t think full intensity conditioning is right for you, they can offer RIC as another option. Older people who need a transplant often get RIC, particularly for acute myeloid leukaemia (AML) and myelodysplastic syndrome (MDS).

You might get RIC alongside medication that suppresses your immune system. This is because your immune system might not be strong enough to completely remove all your blood stem cells.

Ideally, you’d want just the donor stem cells in your blood after your transplant, as close to 100% as possible. But if you have RIC, your blood might end up with a mixture of stem cells from yourself and your donor. You might hear this mixture called a ‘chimerism’ (ky-mer-ih-zum).

Doctors will regularly monitor your chimerism to make sure everything is OK. They might give you a donor lymphocyte infusion (DLI) to boost your immune system and ‘top up’ your chimerism.