Shedding light on childhood cancers

What is cancer?

Cancer is a heterogeneous group of more than 200 different diseases with some common elements. All cancer development results from disrupted cell growth and division. Cancer usually originates in one part of the body but may then spread to other areas.

There are different tissue types (muscles, bones, bone marrow, neural tissue, skin etc) in the human body and all those tissues are made up of cells. The normal cells fulfill their function and they have a finite lifespan. They interact with each other chemically by stimulating or inhibiting growth. The growth and division of the normal cells is controlled and orderly. When cells become old or damaged, they die and some type of cells can be replaced with new cells as needed to keep the body healthy.

How does cancer spread?

Unlike normal cells, most cancer cells appear to have an unlimited capacity to multiply and they are considered somewhat immortal. They live and divide until they have the nutrients needed for them to survive. The reason for that is that the genetic material (DNA) of a cell became damaged or changed which can result in uncontrolled division and growth. When this happens, cells do not die when they should, new cells are formed when the body does not need them and also they do not have the function they should have. The extra cells eventually can form a mass of tissue called a tumor. The cancer cells not only form a mass locally but they are able to invade other parts of the body. They can spread through the blood or lymph system or continuing local growth.

How is cancer diagnosed?

The diagnosis of cancer in children can be difficult, since many of the symptoms are similar to those of other childhood illnesses and since cancer in children is quite rare diagnosis that not many people think about. Symptoms include fatigue, irritability, pains and fever. If these symptoms persist for a while or get worse, or if there are abnormal findings during a medical exam, then medical practitioners may begin to suspect cancer. Blood samples may be taken, and radiography and tomography (CT and CAT scans) may be used to help to identify a problem. The final diagnosis of cancer is most frequently made when the operation is performed and a sample of the tumor is examined under the microscope. Other laboratory tests may be needed to identify the type of the cancer.

Some genetic conditions and certain hereditary illnesses can be associated with an increased risk of childhood cancer. Screening for tumours in children has not proven to be very effective.

Can childhood cancer be prevented?

While childhood cancer causes may not be well known, there are ways to possibly reduce the chance of cancer developing later in life into adulthood. Parents can promote good health by:

Preventing children’s exposure to second-hand smoke
Limiting children’s exposure to sunlight and UV rays
Preventing children’s exposure to asbestos

How common is childhood cancer?

Childhood cancer is rare, and most Canadian children with cancer will survive their disease. According to the Canadian Cancer Society, the most common cancers diagnosed in children (from the ages of 0 to 19 years) are leukemia, brain and spinal tumours, and lymphomas (both Hodgkin and non-Hodgkin).

What are the survival rates?

Forty years of research have led to substantial progress in childhood cancer treatment. On a Canada-wide basis, for all types of childhood cancers combined, the estimated five-year survival rate is 82 per cent. This is an increase of 11 per cent over 15 years.

(Material for this article comes from the Canadian Cancer Society and Leucan Web sites.)