What are the most common types of cancer in children? How do these differ from adult cancers? What methods are used in treatment? All our questions answered by our Pediatric Health and Diseases, Pediatric Hematology, Pediatric Oncology Specialist, Prof. Dr. Nevin Yalman.

What are the most common cancers in childhood?

Childhood cancers differ from those of adults. For example, while respiratory system, digestive system and reproductive system cancers are more common in adults, these cancers are only seen in 5 percent of children. In children, leukemias predominate. According to statistics, 30 percent of childhood cancers are leukemias. Leukemia is followed by brain tumors, lymphomas and soft tissue tumors. Kidney tumors and bone tumors can also be seen in children, although less frequently.

What are the Risk Factors in Childhood Cancers? What is the Effect of Genetic and Environmental Factors?

Genetic predisposition in some families is among the risk factors for childhood cancers. In addition, smoking, environmental pollution, exposure of the child or family to some toxic substances and some drugs also trigger cancer in children.

What is the Success Rate in Leukemia Treatment? Is Bone Marrow Transplantation Used in Treatment?

The chance of treatment for leukemia, the most common childhood cancer, is very high, especially in recent years. We do not perform bone marrow transplantation in every case of leukemia or tumor. Especially in lymphoblastic leukemias, there is a chance of success of up to 90 percent. Chemotherapy may be sufficient in the treatment of these children. However, there is a 13-15 percent risk of recurrence of the disease.
There are some genetic tests used to determine this risk. If these tests are positive and indicate a risk of recurrence if a genetic disorder is detected. In this case, we take the children into the transplant program. As soon as their treatment is completed, we perform bone marrow transplantation.
In acute lymphoblastic and acute myoblastic leukemias, we are primarily in a more anxious situation. Because the chance of success in these is only 60% without bone marrow and the possibility of recurrence is very high. In these cases, we most likely include them in the bone marrow transplant treatment program.

What are the Types of Bone Marrow Transplantation? Which type of transplant is used for which cancers?

Types of bone marrow transplantation are halogenic, that is, transplantation from the patient's sibling, family member, or a stranger who provides tissue group compatibility, and autologous transplantation using the person's own cells. Since autologous transplantation is performed from the person's own stem cells, its risk is lower than halogenic transplantation.

What are Stem Cell Sources?

Although there are different sources for stem cells, our primary source is bone marrow. In patients where bone marrow is preferred as the cell source, cell collection is performed in the operating room under general or epidural anesthesia. In the process of collecting stem cells circulating in the peripheral blood, the donor is connected to a machine and the cells are collected. Umbilical cord blood is ready because it is collected at birth and stored under appropriate conditions.

How Does the Process Work When Transplanted from a Donor?

First of all, the compatibility of antigenic structures is checked by looking at tissue groups. If we can get harmony from our siblings, we have a higher chance of success. However, the chance of success from a sibling is around 25 percent. If we search among relatives, our chance of finding a donor among them is around 6 percent. If they do not have the tissue group, we directly apply to the Turkish Stem Cell Bank in Ankara and send them the test of the tissue group and it is searched within the Bank. The transplantation process is carried out when suitable tissue is found.