It usually involves intense chemotherapy followed by an infusion of stem cells. The treatment requires close nursing and medical care for a number of weeks.
em cell transplant? A stem cell transplant may be used so that you can have intensive high-dose chemotherapy (and sometimes radiotherapy) to kill cancerous cells. The chemotherapy is higher than conventional chemotherapy and also kills the stem cells in the bone marrow that would normally make blood cells. Therefore, following the chemotherapy, you are given back (transplanted) stem cells which can then make normal blood cells again. Stem cells can be obtained from blood as well as from the bone marrow and umbilical cord. So, the term stem cell transplant is now used. What is the bone marrow, and what are stem cells and blood cells? Bone marrow
Blood cells are made in the bone marrow, by stem cells. Bone marrow is the soft sponge like material in the centre of bones. Large flat bones such as the breastbone (sternum) and pelvis contain the most bone marrow. To make blood cells constantly you need a healthy bone marrow. You also need nutrients from your diet, including iron and some vitamins. Stem cells
Stem cells are primitive (immature) cells. There are two main types in the bone marrow - myeloid and lymphoid stem cells. These derive from even more primitive cells called common pluripotent stem cells. Stem cells constantly divide and produce new cells. Some new cells remain as stem cells and others go through a series of maturing stages (precursor or blast cells) before forming into mature blood cells. Blood cells
Mature blood cells are released from the bone marrow into the bloodstream. Mature blood cells are:
Red cells- These make blood a red colour. One drop of blood contains about five million red cells. Red cells contain a chemical called haemoglobin. This binds to oxygen, and takes oxygen from the lungs to all parts of the body. White cells - The different types of white cells are called neutrophils, lymphocytes, eosinophils, monocytes, and basophils. They are part of the immune system. Their main role is to defend the body against infection. Platelets- These are tiny and help the blood to clot if we cut ourselves. Stem cells rapidly multiply to make millions of blood cells each day. Because of this they are more easily killed by chemotherapy than most other cells in the body. This is because chemotherapy drugs work by killing rapidly dividing cells (such as cancer cells). When is a stem cell transplant used for treatment? A stem cell transplant is an option which is considered for various cancer conditions. For example, for types of leukaemia, lymphoma and myeloma. A stem cell transplant is also used for some rare noncancerous blood disorders like aplastic anaemia, thalassemia major etc. There are two main types of bone marrow transplantation: autologous and allogeneic. What are types of stem cell transplant? Autologous transplant — your own hematopoietic stem cells are removed before the high dose chemotherapy or radiation is given and are then frozen for storage and later use. After your chemotherapy or radiation is complete, the harvested cells are thawed and returned to you. Allogeneic transplant — the hematopoietic stem cells come from a donor, ideally a brother or sister with a similar genetic makeup. If the patient does not have a suitably matched sibling, an unrelated person with a similar genetic makeup may be used. Non-myeloablative (mini) transplant — allows you to have less intensive chemotherapy before transplantation with allogeneic hematopoietic stem cells. This approach may be recommended if you cannot undergo standard bone marrow transplantation because of your higher age or other illnesses. Which type of transplant is best for you? — Your physician will determine whether allogeneic or autologous transplantation is best, based on many factors including the type of cancer, your age and overall health, and the availability of a suitable donor. As a general rule, autologous transplantation is associated with fewer serious side effects, since you are given cells from your own body. However, an autologous transplant may be less effective than an allogeneic transplant in treating certain kinds of cancer. In an allogeneic transplant, the donor's immune system, which is generated from hematopoietic stem cells, recognize your cells, including the tumor cells, as foreign and rejects them. This beneficial reaction is called the graft versus tumor effect. In many cancers, the immune response caused by the transplanted cells improves the overall effectiveness of the treatment. This immune response helps kill off any residual cancer cells remaining in your body. A major concern is that you will have an immune response as well, called graft versus host disease. Where are stem cells obtained from? Stem cells can be collected:
1) Bone marrow- This involves a small operation to collect some marrow from the pelvic bone.
2) Peripheral blood- Some stem cells occur in the blood (most are in the bone marrow). The stem cells in the blood can be collected (harvested) by a machine called a cell separator. The blood flow is diverted from a vein in the arm to pass through the machine which separates out the stem cells. The procedure takes about 4-6 hours. Drugs are given for a few days before this procedure to stimulate the body to make more stem cells in the bone marrow which spill out into the blood.
3) Umbilical cord of a newborn baby. How is a stem cell transplant given? It is very similar to a blood transfusion. Following the intense course of chemotherapy (and sometimes radiotherapy), the solution containing stem cells is given into one of your veins via a drip. The stem cells travel through your bloodstream and end up in your bone marrow. Here they start to make blood cells. It can take several weeks for your bone marrow to recover, to take up the transplanted stem cells, and to make enough new blood cells. During this time you will need to be in hospital and be closely monitored. You may need several blood transfusions during this time until you are making enough blood cells. Antibiotics are given to minimize the risk of infection. Also, drugs are given to help stimulate the stem cells to multiply as quickly as possible. What are the main risks of having a stem cell transplant? There is a risk of serious problems with a stem cell transplant. For example:
• Infection is the main risk. Following the intense chemotherapy, and before the time your bone marrow is working again, you have very low immunity. During this time you are at risk of serious and life-threatening infections. This is why antibiotics are given and you will be nursed away from other people until your bone marrow recovers. This can take several weeks.
• Bleeding problems from the low level of platelets after the chemotherapy.
• It you have a transplant from a donor; there is some risk that the match will not be perfect, and the donor cells may react with your body's cells. This is called graft versus host disease. This is not always serious but sometimes it can be.
• Rarely, the transplanted stem cells fail to work (Graft failure).
• There is a risk of short-term and long-term side-effects from intense chemotherapy (and/or radiotherapy). Dr Niranjan N Rathod
DM, MD, FACP (USA), Fellowship in BMT, FHCRC, Seattle, USA
Associate Director & Head of Dept of Haemato-Oncology & Bone Marrow Transplant
Nanavati Super Speciality Hospital, Vile Parle West, Mumbai. Ph-02226140046
Mobile-9930767546
