Treatment of blood diseases and children’s cancer

Recently, a team of specialist children’s cancer pediatricians, led by Prof. Suradej Hongeng, M.D., Asst. Prof. Samart Phakakasama, M.D. and Phonchanok Iamsirirak, M.D., Thailand’s leading pediatric specialists in blood diseases and children’s cancer, successfully treated child patients for leukemia and thalassemia using a bone marrow transplant, or, as the procedure is also known, haploidentical hematopoietic stem cell transplantation. In the past, doctors had been unable to use this method due to mismatches in the bone marrow of patient and donor. Many patients showed resistance to their donor’s bone marrow, and therefore had to spend long periods of time waiting for a matching bone marrow sample. Consequently, some patients passed away before receiving treatment. This inevitably causes great concern among the parents of child cancer patients, who want nothing more than for their child to make a full recovery and overcome the condition.

Patients will first receive chemotherapy to weaken the immune system. Then, after arriving at the bone marrow transplant operating room, the patient will be given an increased dose of chemotherapy drugs to help remove damaged blood cells and make room for new, healthy stem cells. Parents who are to donate stem cells will be injected with a drug that stimulates white blood cell production for around 4-5 days. The blood stem cells will then be harvested using a catheter, after which the harvested cells can be transferred to the patient. Around 2-3 weeks later, the parents’ donated stem cells will begin to function normally, but the patient will still be required to take immunosuppressant drugs for around 6 months.

Children’s cancer is a very worrying issue for parents, because a child who suffers from cancer is likely to miss out on much of what life has to offer. A child cancer patient will not be able to play or be as happy and carefree as other healthy children, and may also be affected by growth failure in later life. In Thailand, among children up to age 15, around 1,200 cancer diagnoses are reported each year, with the most common children’s cancer being leukemia. Other types of cancer diagnosed in children include brain tumors, lymphoma, adrenal cancer, renal cancer, bone cancer, liver cancer and eye cancer. Only 1-3% of children’s cancers are thought to be hereditary, as in the case of eye cancer, but for most other types of children’s cancer, there is no identifiable cause. Children’s cancer is much easier to treat than cancer in adult patients, however, as cancer cells in a child undergo much less genetic mutations than in an adult. A child’s cells all have similar characteristics, which means that they respond to treatment in the same way and respond to treatment well.

Leukemia, the most common form of children’s cancer, is divided into two types: acute leukemia (which develops suddenly) and chronic leukemia (which develops slowly). About 90% of cases are classed as acute leukemia, which can then be subdivided into acute lymphoblastic leukemia (ALL), which makes up around 80% of all acute leukemia diagnoses, and myeloid leukemia (AML), which makes up the remaining 20%. At present, the survival rate for ALL patients treated with chemotherapy treatment is around 80%. For AML patients treated with chemotherapy, however, the survival rate is around 50%, but the AML patient’s chances of survival can be increased by 80% if treated early with a bone marrow transplant.

The patient’s symptoms will depend on the type of cancer. For example, patients may experience symptoms such as fatigue, fever and easy bleeding, which often leads to large bruises on the arms and legs. Patients may also experience swollen lymph nodes or an enlarged liver or spleen. This is because the patient’s bone marrow has been attacked by cancer cells, so the body is unable to produce a normal level of white blood cells. A patient with a low white blood cell count is also prone to infection. However, not all leukemia patients will experience symptoms of fatigue or easy bleeding. Fatigue may be due to iron deficiency or thalassemia, which is a hereditary condition. If your child experiences any of these symptoms, therefore, you should see a doctor immediately to make sure he or she gets the right treatment.

Leukemia treatment is usually based on a 1- to 3-year course of chemotherapy, depending on the type of cancer. Child patients have a higher chance of recovering from cancer than adults, as cancer cells in children undergo less genetic mutations than in adults. Children, therefore, usually respond well to cancer treatment, with a recovery and survival rate of around 75%. (This means that, after 5 years since stopping treatment, the cancer does not return and the patient is usually fully recovered.)

1. Bone Marrow Transplant

If a patient’s leukemia is resistant to chemotherapy, then a bone marrow transplant may be used instead. A bone marrow transplant costs around 800,000 – 1.5 million baht per person, and the patient will be required to stay in a sterile room for around 1-2 months following treatment. Only when the patient’s white blood cell production has returned to normal will the patient be allowed to leave the sterile room.

2. Stem cell transplant

A stem cell transplant does not require surgery, but does require a large amount of chemotherapy. Chemotherapy may be used in combination with radiotherapy to ensure that the patient’s cancerous bone marrow is destroyed. A stem cell will then be taken from the bone marrow at the back of the donor’s pelvis, which will then be transferred to the patient intravenously so that the stem cells can enter the bone marrow and start producing white blood cells normally again. Harvesting bone marrow using a syringe does not affect the spine, so this method presents no risk of paralysis. Additionally, changes in the transplant procedure mean that the bone marrow can still be used to treat other blood diseases, such as thalassemia and congenital immune deficiency diseases. However, stem cells from the donor will need to carry a special genetic marker – known as a human leukocyte antigen (HLA) – that is identical to that of the patient. There is a 25% chance that a patient’s sibling will carry a matching HLA, so this does not mean that a sibling will always be able to provide the correct stem cell for the patient. There are, however, non-siblings who share a matching HLA at a ratio of around 1:50,000. Finding a non-sibling with a matching HLA therefore requires an extensive search. In Thailand, the National Blood Center run by the Red Cross Society gathers information about bone marrow donors. However, the chance that there is a donor in Thailand with an HLA that matches the patient is around 50%.