General Information About Unusual Cancers of Childhood
Key Points for This Section
Cancer in children and teenagers is rare. Since 1975, the number of new cases of childhood cancer has slowly increased. Since 1975, the number of deaths from childhood cancer has decreased by more than half.
Unusual cancers are so rare that most children's hospitals might see less than a handful of some types in several years. Because the unusual cancers are so rare, there is not a lot of information about what treatment works best. A child's treatment is often based on what has been learned from treating other children. Sometimes, information is available only from reports of the diagnosis, treatment, and follow-up of one child or a small group of children who were given the same type of treatment.
Many different cancers are covered in this summary. They are grouped by where they are found in the body.
Tests are done to detect, diagnose, and stage cancer. The tests used depend on the type of cancer. After cancer is diagnosed, tests are done to find out if cancer cells have spread from where the cancer began to other parts of the body. The process used to find out if cancer cells have spread to other parts of the body is called staging. The information gathered from the staging process determines the stage of the disease. It is important to know the stage in order to plan the best treatment. The following tests and procedures may be used to detect, diagnose, and stage cancer:
- Physical exam and history : An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.
- Blood chemistry studies : A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that makes it.
- Biopsy : The removal of cells or tissues so they can be viewed under a microscope by a pathologist to check for signs of cancer. There are many different types of biopsy procedures. The most common types include the following:
- Excisional biopsy : The removal of an entire lump or area of tissue that doesn’t look normal.
- Incisional biopsy : The removal of part of a lump or a sample of tissue that doesn’t look normal.
- Core biopsy : The removal of tissue using a wide needle.
- Fine-needle aspiration (FNA) biopsy : The removal of tissue or fluid using a thin needle.
- X-ray : An x-ray is a type of energy beam that can go through the body and onto film.
- CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
- PET scan (positron emission tomography scan): A procedure to find malignant tumor cells in the body. A small amount of radioactive glucose (sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the body. Malignant tumor cells show up brighter in the picture because they are more active and take up more glucose than normal cells do.
- MRI (magnetic resonance imaging): A procedure that uses a magnet and radio waves to make a series of detailed pictures of areas inside the body. The pictures are made by a computer. This procedure is also called nuclear magnetic resonance imaging (NMRI).
- Ultrasound exam: A procedure in which high-energy sound waves (ultrasound) are bounced off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. The picture can be printed to be looked at later.
- Endoscopy : A procedure to look at organs and tissues inside the body to check for abnormal areas. An endoscope is inserted through an incision (cut) in the skin or opening in the body, such as the mouth or rectum. An endoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue or lymph node samples, which are checked under a microscope for signs of disease.
- Bone scan : A procedure to check if there are rapidly dividing cells, such as cancer cells, in the bone. A very small amount of radioactive material is injected into a vein and travels through the bloodstream. The radioactive material collects in the bones and is detected by a scanner.
The three ways that cancer spreads in the body are:
- Through tissue. Cancer invades the surrounding normal tissue.
- Through the lymph system. Cancer invades the lymph system and travels through the lymph vessels to other places in the body.
- Through the blood. Cancer invades the veins and capillaries and travels through the blood to other places in the body.
When cancer cells break away from the primary (original) tumor and travel through the lymph or blood to other places in the body, another (secondary) tumor may form. This process is called metastasis. The secondary (metastatic) tumor is the same type of cancer as the primary tumor. For example, if breast cancer spreads to the bones, the cancer cells in the bones are actually breast cancer cells. The disease is metastatic breast cancer, not bone cancer.