Leukaemia & Transplantation

Introduction

There are many types of treatment for leukaemia. These treatments differ depending on the classification of the disease and are different for children and adults. The following information is intended as a guide to inform readers of the most commonly used treatments for leukaemia and other serious blood diseases. Your doctor or health care professional is the best person to discuss the specifics of your case with you.


Left: Peripheral blood smear showing blast crisis of chronic myelogenous leukaemia Right: Histopathology of toxoplasmosis of lung. Complication of chronic myelogenous leukemia.

Chemotherapy

Chemotherapy is the use of cell-killing (cytotoxic) drugs aimed at eradicating the malignant leukaemia cells. Unfortunately the drugs do not only attack the malignant cells and many of the drugs have side effects as normal tissue is also affected. Most of the side effects are temporary. The initial treatment of newly diagnosed patients with acute leukaemias involves the use of combinations of anti-cancer drugs with the intention of inducing complete remission. The choice of drugs and the timing of treatment will vary. A variety of drugs may be used either alone or in combination. Further courses of cytotoxic drugs may be given as maintenance treatment for months or years after remission has been achieved. Chronic myeloid leukaemia (CML) can be managed with a new drug called Glivec which is not effective in any other form of leukaemia. If Glivec is not successful then other therapies such as Interferon or stem cell transplantation can be used.

Radiotherapy

Radiotherapy uses high energy rays to destroy cancer cells while doing as little harm as possible to normal cells. Radiotherapy is often used when the disease is seen to be confined to one area of the body, which is sometimes the case in lymphomas.

Bone Marrow or Stem Cell Transplant

The terms bone marrow transplant and stem cell transplant refer to the same medical process. The difference between them is the way the cells are harvested. Bone marrow harvest takes place in the operating theatre. The stem cells are aspirated directly from the hip bones whilst the patient is under general anaesthetic. Peripheral blood stem cells are harvested on a cell separator machine after the patient has completed a course of chemotherapy and /or growth factor injections. If the cells are being collected from a donor, the donor will not be given chemotherapy, just a short course of growth factor injections. Transplants aim to eradicate abnormal leukaemic cells and repopulate the patient's bone marrow with healthy cells. These transplants can be allogeneic, where a matched donor (usually a brother or sister) supplies marrow or stem cells, or autologous, where the patient's own stem cells and/or marrow are harvested and then returned following chemotherapy. Autologous cells are collected when the patient has achieved remission.

Transplant Process

After high dose chemotherapy or chemo-radiation is given to destroy the existing marrow cells and to treat the underlying disease, the cells are reinfused in order to reconstitute the patient's blood and immune systems. Allogeneic transplants are most often carried out where the donor is an HLA-matched sibling (a brother or sister). In situations where no siblings are HLA-identical (70% of cases) and an autologous transplant is not appropriate, donor registries worldwide can be searched to find a matched unrelated donor. The Australian Bone Marrow Donor Registry (ABMDR) currently has thousands of potential donors available.