Stem Cell Transplants

Stem cells are young immature blood cells that are created inside our bone marrow. They will become red blood cells, white blood cells and platelets when they have matured fully. Sometimes the bone marrow can be damaged by cancer and it can also be damaged by chemotherapy and radiation. If this happens the stem cells may not make enough blood cells and they may also make a lot of abnormal blood cells. Because we need healthy blood cells to survive, some people need a stem cell transplant to replace stem cells from bone marrow that isn´t working properly.

Our blood is made up of 3 main types of blood cells: red blood cells, white blood cells and platelets. All cells in our body need oxygen to survive and it is the job of the red blood cells to transport oxygen from our lungs around the body to all the cells. The red blood cells are also responsible for getting rid of carbon dioxide by transporting it from the body cells back to the lungs where we breathe it out. The white blood cells are an important part of our immune system to help fight infections. And the platelets are blood cells that help to seal up damaged blood vessels and they are important to help the blood clot so that we stop bleeding if for example we cut ourselves or have a nosebleed.

The blood cells are created in the bone marrow, which is a soft spongy substance inside our bones. When the blood cells are young and immature, they are called stem cells. In fact, they are called hematopoietic stem cells because the word ‘hematopoietic’ means ‘blood-forming’ but usually we just call them stem cells.

Sometimes the bone marrow can be damaged by cancers such as leukemia and it can also be damaged by chemotherapy and radiation. If this happens the stem cells might not make enough blood cells and they may also make a lot of abnormal cells. Because blood cells are so important for all the cells in our body, some people need a stem cell transplant to replace bone marrow that isn’t working properly.

Stem cell transplant can also be an important part of treating cancer, for example in people who have certain leukemias, lymphomas or multiple myeloma. Sometimes it is important to give really high doses of chemotherapy and/or radiotherapy to have a better chance of killing the cancer cells. But it’s risky to give very high doses of treatment as it can cause the bone marrow to stop making blood cells and of course we need blood cells to live. Therefore, in situations where doctors have to give such strong doses of chemotherapy/radiotherapy they can use ‘stem cell transplant’ to help the person cope with the tough treatment. In those situations they give a person healthy stem cells after the high doses of treatment has destroyed the person’s bone marrow and their own stem cells (remember we need the stem cells to produce healthy blood cells).

There are different types of stem cell transplants depending on who gives the stem cells that will be transplanted. When we talk about ‘transplant’ we probably think of transplanting from one person to another. That is one type but there is also a type of stem cell transplant where people get the stem cells from themselves. In this type of stem cell transplant, healthy stem cells are taken out of the bone marrow before a person is given the high dose chemotherapy/radiotherapy that will destroy the stem cells. The healthy stem cells are then frozen during treatment and given back to the person after the high dose treatment. One advantage of using the person’s own stem cells is that the body will not reject them, which can happen when a person receives stem cells from another person.

It's not always possible to use the person's own stem cells and when the stem cells come from a donor they have to be a close match (with regard to tissue type) to the patient who needs the stem cells. Sometimes this can be a family member but other times they have to find a donor through a national donor registry. After the stem cells have been harvested (taken) from a donor, they are frozen until the patient has finished the high dose treatment. Then when the patient is ready to get the healthy stem cells, they are defrosted and infused into a vein like a blood infusion.

This may sound a bit complicated but if you want to find out more we have linked to Maggie’s CancerLinks where you will be signposted to high quality information about different types of cancer treatments, including stem cell transplants.

Please get in touch with us if you have any worries or questions related to cancer.

Page updated 17 July 2017