The Gift of Life: Stem Cell Transplant

22 November 2021

Stem cell transplant is an opportunity for people with cancer or blood disorders to have a second chance at life. Hematopoietic stem cell transplant or bone marrow transplant is the process of transplanting healthy stem cells to a person whose bone marrow is failing, damaged or no longer functioning properly.

Sunway Medical Centre Consultant Haematologist Dr Henning Loo Cheng Kien explains that bone marrow is the factory that makes most of our blood cells including red blood cells, while blood cells and platelets. All the cells made in the bone marrow are known as stem cells, giving haematopoietic stem cell transplant its name.

He noted that haematopoietic stem cell transplants are mainly used to treat blood disorders such as leukaemia, multiple myeloma and myelodysplastic syndrome as well as thalassaemia, lymphoma and other oncological diseases.  

Types of transplant

There are two types of stem cell transplants – autologous which uses the patient’s own stem cells and allogeneic which uses a donor’s stem cells.

 For allogeneic transplant, the patient must have a Human Leukocyte Antigen (HLA) match – usually a sibling or an unrelated donor is there is no direct blood relative match.

Stem cell transplant for allogeneic transplant can now be semi-anastomosed with haematopoietic stem cell transplant (HSCT), which means the stem cells can be transplanted from a parent or sibling who is a half-match.

When it comes to finding a bone marrow donor in Malaysia, Dr Loo said patients can search for a matching non-blood-damaged donor from stem cell databases in Malaysia and abroad. The search is free but once a match is found and the patient wants the stem cell, a cost is incurred.

He noted that autologous transplant is mainly used to treat lymphoma, multiple myeloma and other oncological diseases, while allogeneic transplants are used to treat blood cancers, aplastic anaemia, myelodysplastic syndromes and haemoglobinopathies.

Stem cell transplant procedure

The procedure involved varies from disease to disease but generally, the patient’s condition is first accessed to see if his condition is acceptable for transplantation. If so, the patient or donor is injected with G-CSF to mobilise stems cells from the bone marrow into the peripheral blood.

This is followed by an apheresis where the patient or donor’s blood is drawn and stem cells are separated from the blood and collected by a machine and frozen.

Next, the patient is given pre-transplant conditioning therapy. This treatment uses high doses of chemotherapy or radiotherapy to eliminate cancer cells from the patient’s body which also destroys the patient’s immune system and bone marrow to make room for new stem cells.

Stem cell transplant is similar to blood transfusion and is administered through a central venous catheter into the patient’s body. It usually takes 8 to 14 days for the patients to produce new blood cells after stem cell transplant.

Dr Loo said there are some immediate and long-term side effects after stem cell transplant including vomiting, diarrhoea, mouth ulcers and skin rashes when patients receive intensive chemotherapy or electrotherapy.

There a few long-term side effects in autologous transplants while allogeneic transplant can cause side effects known as Graft versus host disease (GvHD) and various complications such as lung, liver and intestinal complications.

“Although transplanted stem cells are compatible with the patient, they are not 100% compatible therefore the donor’s cells will attack the patient’s organs during the infusion process. GvHD causes diarrhoea and affects lung function,” Dr Loo said.

Other long-term chronic side effects are the possibility of infertility in young patients and secondary cancers where patients may develop other cancers which they would otherwise not have, and damage to organs such as the lungs and liver.

Patients are also susceptible to death during the stem cell transplant process or from complications, with a mortality rate of 3% to 5% for autologous transplants and 10% for allogeneic transplants, Dr Loo said.

Extending patients’ lives

Dr Loo said the survival rate varies from disease but studies have shown that stem cell transplant can prolong lives compared to those who do not undergo this treatment.

Sunway Cancer Centre provides a one-stop, comprehensive treatment for patients with leukaemia and other haematological and oncological diseases. It offers autologous and allogeneic stem cell transplantation services in addition to cancer therapies including surgery, chemotherapy and electrotherapy.

The haematology team also includes Consultant Haematologists, Dato' Dr Chang Kian Meng and Dr Hon Siong Leng, who work with a multidisciplinary team to tailor the treatment to the patient's condition.

Source: Sin Chew Sabah