About high-dose (conditioning) treatment

When everything is prepared for your autologous stem cell transplant and your stem cells have been collected, you have high-dose treatment.

High-dose treatment (also called conditioning treatment) is given to destroy as many cancer cells as possible. You will have high doses of chemotherapy. Rarely, people also have radiotherapy to the whole body. This is called total body irradiation (TBI).

Going into hospital

You will be treated in a cancer unit that specialises in this treatment. Some people may need to travel quite far to their nearest unit. 

You usually stay in hospital to have the treatment. The treatment may only last a day or a few days, but you are usually in hospital for a few weeks. This is because you need to wait for your blood count to recover. This can take 2 to 3 weeks

Some units offer what is called ambulatory care. This is where you go to the hospital during the day. If you are well and live nearby you can go home at night. If you live further away the hospital can arrange somewhere to stay nearby. You may need to have someone staying with you. If you become unwell you will be admitted to the hospital. You can talk to your doctor or nurse about whether ambulatory care is possible for you.

Teenagers and young adults

Some hospitals have teenage and young adult cancer units (sometimes called TYA units). You will be with other people your own age and cared for by people who are used to working with teenagers and young adults.

There may be internet access, a computer, games consoles, DVDs and music to help you feel more at home. Sometimes education specialists come to support you with your studies while you are having treatment.


Visitors, especially close family, friends and your partner, if you have one, are important. They give you support and help you stay in touch with life outside hospital. Some units have rooms for family members to stay overnight if they have far to travel.

Most units are flexible about visiting, but different hospitals have different rules. You may be restricted to a certain number of visitors each day. This is to help protect you from infection. The nurses will explain more about this to you.

Conditioning with chemotherapy

The nurses will give you chemotherapy drugs into a vein through your central line or PICC line, along with plenty of fluids. Some people may have some of their chemotherapy as tablets. You usually have a combination of chemotherapy drugs. Your nurse will explain the possible side effects and give you drugs to help control them.

The treatment is given over one day or a few days. This depends on the type of cancer you have.

Conditioning with total body irradiation (TBI)

Radiotherapy uses high-energy rays to destroy cancer cells. TBI treats your whole body with radiotherapy. Some people have it as part of their high-dose treatment. You usually have it a few days after you start chemotherapy.

You may have TBI twice a day for 6 to 8 sessions. This is usually over 3 to 4 days.

You will have a planning session in the radiotherapy department a few days before you have TBI. The doctor, nurse or radiographer (person who gives the treatment) will explain more about the treatment and its side effects.

Before each session, the radiographer positions you carefully and makes sure you are comfortable. Radiotherapy is not painful, but you need to keep still during the treatment. You have radiotherapy to both sides of your body. This means you need to change position a few times during the session. The radiographer will explain this to you.

Each session lasts about 40 minutes. The radiotherapy itself only takes about 10 to 20 minutes. You can bring some music to listen to during your treatment.

Side effects of TBI

Possible side effects of TBI include:

  • skin changes
  • tiredness
  • feeling sick
  • diarrhoea
  • loss of appetite
  • dry mouth
  • sore mouth.

These can happen a few days after the treatment. Your team will explain how to manage the side effects and how to care for your skin. 

We have more general information about radiotherapy.

Having your stem cell infusion

Your stem cells will be given back to you 1 or 2 days after the high-dose treatment has finished. The day you are given your stem cells is known as Day 0.

Your nurse gives you the stem cells as a drip (infusion) through your central line or PICC line. It is like having a blood transfusion.

Some people have mild side effects while the stem cells are being given, such as feeling sick or breathlessness. Your nurse will give you drugs through your central line before the stem cell infusion. This is to reduce the risk of an allergic reaction. They monitor you carefully during and after the stem cell infusion.

You and your visitors might notice a strong smell like sweetcorn. This can last for a few days after the infusion. This is from the preservative that is used to protect the stem cells during storage.

Waiting for your new blood cells to grow

The stem cells travel through your blood to your bone marrow. They then begin to make new blood cells. This is called engraftment. 

It usually takes 10 to 12 days before some of the new blood cells are released into the bloodstream. For some people, it may take longer. This means you will have low numbers of red blood cells, white blood cells and platelets for some time. This can cause some of the main side effects. During this time, you are at high risk of infection and other problems, such as bleeding and anaemia (low red blood cells).

You will have blood samples taken every day to check your blood count. You may need transfusions of blood or platelets to help. You may also need antibiotics.

You may be given a drug called G-CSF as an injection. It helps your bone marrow make new blood cells. This reduces the length of time you are at risk of side effects.

Your daily routine

If you are in hospital, you may expect to have a lot of quiet time. But your day can be quite busy. A lot of your time will be taken up with daily routines and checks by the doctors and nurses. This may include:

  • taking blood samples from and giving medicines into your line
  • changing your drip (infusion) of fluids when needed
  • taking your temperature, pulse and blood pressured
  • examining your tummy and mouth and checking your weight
  • measuring the fluid you take in and the fluid you pass out (fluid balance)
  • checking your central line or PICC line.

Preparing to go home

When your blood count has reached a safe level and you are improving, you can go home. You will need some support at home from a relative, friend or partner. The hospital can also arrange some help for you. You will have a 24-hour telephone contact number in case you have any worries. You will need to go back to the hospital regularly as an outpatient for check-ups.

Support from Macmillan

Macmillan is here to support you. If you would like to talk, you can:

About our information

  • References

    Below is a sample of the sources used in our stem cell and bone marrow transplants information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk

    Carreras, Dunfour, Mohty and Kröger. The European Society for Blood and Bone Marrow Transplantation: Hematopoietic stem cell transplantation and cellular therapies. Springer, Switzerland. 2019. 

    FACT-JACIE International Standards for Hematopoietic Cellular Therapy – product collection, processing and administration. 7th edition. 2018. 

    Anthony Nolan. Operations and patient services user guide. Available from www.anthonynolan.org. Accessed January 2019.

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editor, Dr Anne Parker, Consultant Haematologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

The language we use

We want everyone affected by cancer to feel our information is written for them.

We try to make sure our information is as clear as possible. We use plain English, avoid jargon, explain any medical words, use illustrations to explain text, and make sure important points are highlighted clearly.

We use gender-inclusive language and talk to our readers as ‘you’ so that everyone feels included. Where clinically necessary we use the terms ‘men’ and ‘women’ or ‘male’ and ‘female’. For example, we do so when talking about parts of the body or mentioning statistics or research about who is affected. Our aims are for our information to be as clear and relevant as possible for everyone.

You can read more about how we produce our information here.