Understanding stem cell transplants

Bone marrow is the spongy tissue inside some of your bones, such as your hip and thigh bones. It contains immature cells known as stem cells, and these stem cells can transform into red blood cells, white blood cells and platelets.  

Red blood cells carry oxygen to all parts of your body, white blood cells fight off infections and platelets help blood to clot to stop bleeding.

Stem cells are also found in the blood in our veins and arteries. These are known as peripheral blood stem cells. Another source of stem cells is from the placenta of a newborn baby’s umbilical cord.

What is a stem cell transplant?

When the body is weakened by disease or from treatment of disease such as the toxic effects of cancer drugs used in chemotherapy, stem cells are then needed to replenish the body’s supply of healthy blood-forming cells.

And this is what is referred to as a stem cell transplant. It is also known as bone marrow transplant or an umbilical cord blood transplant, according to where the stem cells are taken from.

“Stem cell transplant has been established in Singapore since 1985 and it has since become a routine treatment,” says Dr. Freddy Teo Cheng Peng, a haematologist from Parkway Cancer Centre at Gleneagles Hospital.

Stem cell transplants can be used to treat cancerous as well as non-cancerous diseases.

Different types of stem cell transplant

There are two main types of stem cell transplant:

nAllogenic transplant – where the stem cells are donated by  parents, siblings; or by an unrelated person

n Autologous transplant – the patient receives his or her own stem cells

The third type of stem cell transplant is syngeneic transplant, where stem cells are taken from the patient’s identical twin.

Allogenic stem cell transplant

This is commonly used to treat the different types of leukaemia and other bone marrow disorders. In this instance, stem cells are taken from a donor whose tissue type best matches the patient.

Most times, the donor is a family member, usually a sibling. If the patient is unable to find a good match within the family, the doctor will turn to a national registry and usually, a match can be found.

A newer source of stem cells is from cord blood. However, the amount of stem cells is often insufficient for adults. Hence, this source is mostly for children.

Advantages of allogenic transplant

n Stem cells from healthy donor are free of cancer cells.

n The donor stem cells can produce immune cells which can help destroy the recipient cancer cells that remain after high-dose cancer treatment.

nThe donor can be recalled to donate more stem cells when needed.

Disadvantages of allogenic transplant

n The donor cells are more likely to die or be destroyed by the recipient’s immune system.

nThe donor cell may produce new immune cells that attack the recipient’s body – a condition known as graft-versus-host-disease.

nRisk of infection from donor cells although this risk is minimal because donors are carefully screened before they can donate.

Autologous stem cell transplant

This is used mainly to treat lymphomas, acute myeloid leukaemia, multiple myeloma and other cancers.

You are your own donor, using stem cells from your bone marrow or blood. The stem cells are harvested before you undergo high doses of chemotherapy or radiation therapy, or both. After you have undergone chemotherapy or radiation, the stem cells which have been stored will be taken out and put back into your body.

Advantages of autologous transplant

nBecause you are getting your own stem cells, there is no risk of rejection or of the transplanted cells attacking your body.

Disadvantages of autologous transplant

nThere is a chance that cancer cells are harvested together with the stem cells. To reduce this risk, doctors may treat the harvested cells with cancer drugs or other therapies to reduce the number of cancer cells that may be present.

nDepending on the condition of your disease, your doctor will advise you accordingly the type of stem cell transplant that is most suitable for you.

Inspired by a patient’s zest for life

One such case is Karta Winata. Diagnosed in April 2005, Winata was 68 years old when he was taken under the care of Dr. Freddy Teo Cheng Peng at the Parkway Cancer Centre at Gleneagles Hospital.

At the time, Karta could not walk and had complications to his brain and kidney as a result of multiple myeloma. Chemotherapy – the most common procedure to first treat cancer – was administered to kill the myeloma cells from multiplying rapidly in Mr Karta’s body.  

Due to the advanced stage of Karta’s diagnosis, an autologous stem cell transplant was carried out to improve his chances of recovery. This procedure involves a removal of the patient’s healthy stem cells, which are then frozen and stored before a high dosage of chemotherapy drugs are administered into the body. The stored stem cells are then thawed and transfused back to the patient to eliminate any remaining myeloma cells in the body.

Speaking highly of Karta, Dr. Teo praises the Indonesian for his resilience and positive outlook in life. “Although he encountered some setbacks while undergoing the treatments, Mr Karta’s zest for life motivates me to do better in caring for cancer patients,” Dr. Teo says.  

According to Dr. Teo, stem cell transplants are not an easy treatment as there are risks associated with the treatment. In Karta’s case, his elderly age and a physically unfit body did not act in favour of the major cancer procedure.

The oncologist had a change of mind and heart upon realising Karta’s will and courage to survive. Due to this positive outlook on the transplant, Dr. Teo went ahead with the Autologus Stem Cell Transplant in 2006.

Nursing Manager at Parkway Cancer Centre Sister Tay Sok Har, who cared for Karta throughout his treatment procedures, shares her positive nursing experience: “It is such a joy taking care of him. He always has a jovial disposition.”

Karta, who undergoes the autologous stem cell transplants every two months, mentioned his family as his pillar of hope and strength. Flashing a smile, he adds, “I look forward to becoming healthy again.”  

Outlook for stem cell transplant patients

Dr. Teo says that patients who undergo autologous stem cell transplant which uses their own stem cells recover faster than those who go through allogenic stem cell transplant, using stem cells from donors.

Usually, it takes about one year for the patient’s blood cells and immune system to restore to normal levels following a stem cell transplant. “For some people, stem cell transplant can cure their disease. With others, the transplant may put the disease that they are suffering from into remission,” says Dr. Teo.

Depending on the individual, some stem cell transplant patients do not suffer from any side-effects and complications. Others may experience mild to severe side-effects. As with most treatments, the success of stem cell transplant differs from one person to another.

“The good news is that many people who have undergone stem cell transplant have gone on to live a normal, active life,” says Dr. Teo.

Dr. Teo explains that autologous transplant is superior over allogenic transplant because there is no need for a donor. And, because you are using your own stem cells, they are a perfect match. “In some instances, it’s used as a part of treatment for solid cancer tumours which require a high dose of chemotherapy to wipe out the malignant cells.”

ParkwayHealth

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