Typically, factors that trigger cancer in kids usually differ from those that cause cancer in adults, such as smoking or exposure to environmental toxins. Rarely, there may be an increased risk of childhood cancer in kids who have a genetic condition, such as Down syndrome. Those who have had chemotherapy or radiation treatment for a prior cancer episode may also have an increased risk of cancer. Among the major types of childhood cancers, leukemias (blood cell cancers) and cancers of the brain and central nervous system account for more than half of the new cases. About one-third of childhood cancers are leukemias. The most common type of leukemia in children is acute lymphoblastic leukemia. Kids with cancer can be given the chemotherapy medications intravenously (through a vein) or orally (by mouth). Some forms of chemotherapy can be given intrathecally, or into the spinal fluid. The drugs enter the bloodstream and work to kill cancer in all parts of the body. Kids with certain types of cancer can also receive bone marrow transplants at our hospital. Bone marrow is a spongy tissue inside certain bones of the body that produces blood cells. If a child has a type of cancer that affects the function of blood cells, a bone marrow transplant (along with chemotherapy to kill the defective cells) may allow new, healthy cells to grow. Radiation is one of the most common treatments for cancer in children. A child who receives radiation therapy is treated with a stream of high-energy particles or waves that destroy or damage cancer cells. Many types of childhood cancer are treated with radiation along with chemotherapy or surgery.
Types of childhood cancer
- Acute Lymphoblastic Leukemia is the most common type of childhood cancer. It is a cancer of the blood system, starting in the bone marrow and percolating out into the blood. These patients have too many immature white blood cells in their blood and bone marrow. Fully developed lymphocytes fight infection by attacking germs and other harmful bacteria in the body, whereas lymphoblasts are harmful.
- Central Nervous System (CNS) tumors are cancers of the brain and brain stem. They are the most common solid tumors of childhood and they have the highest mortality rate of the childhood cancers. Types include medulloblastoma, PNET, germ cell tumors, high-grade and low-grade gliomas, ependymoma, astrocytoma and more.
- Clear cell sarcoma of the kidney (CCSK) is a very rare type of kidney tumor. It is not recognizable as different from Wilms tumor before removal of the tumor, but requires a different treatment.
- Ewing Sarcoma is a less common form of bone tumor, affecting mostly children ages five and older. These tumors form in the cavity of the bone.
- Hodgkin disease is a type of lymphoma, a cancer of the lymph nodes. It affects teens most commonly, but also younger children. The lymph system is present throughout the body and helps fight infections. Hodgkin disease can start almost anywhere and then spread to almost any organ or tissue, including the liver, bone marrow and spleen.
- Myeloid leukemias are more rare and difficult to cure than the more common Acute Lymphoblastic Leukemia (ALL). In leukemia, the bone marrow produces large numbers of abnormal blood cells which flood the bloodstream and lymph system and may invade vital organs. The most common cancer of the myeloid cells is Acute Myeloid Leukemia (AML). Others include Juvenile Myelomonocytic Leukemia (JMML), Chronic Myelogenous Leukemia (CML), Acute Promyelocytic Leukemia (APL), and Myelodysplastic Syndromes (MDS). While adults are much more likely to get AML than children, treatment for children with AML is different from that of adults.
- Neuroblastoma is a cancer of the sympathetic nervous system, a nerve network outside the brain. Neuroblastoma tumors can grow in the abdomen, neck or pelvis. The average age of diagnosis is 2, and it is rare in children over 10 years old.
- Non-Hodgkins Lymphomas are cancers of the cells of the immune system (T and B lymphocytes, natural killer cells). Cells of the immune system are produced in the bone marrow and then travel to all the lymph glands, the thymus gland, areas of the intestinal tract, tonsils, and spleen, so a lymphoma can develop in any of those sites. The four major subtypes of NHL in children are Lymphoblastic, Burkitts, Large B cell, and Anaplastic large cell.
- Osteogenic sarcoma (or osteosarcoma) is the most frequently diagnosed type of bone tumor, usually found in adolescents and young adults. Tumors are most often in the large bones of the upper arm (humerus) and the leg (femur and tibia).
- Retinoblastoma is a cancer of the retinoblasts, or "baby" cells in the retina, responsible for vision. Retinoblastoma occurs most often in children from birth to age 3. About 40% of these children have the genetic form of the disease; with every cell in the retina susceptible to tumor formation, usually both eyes are affected. The other 60% have the non-genetic type, affecting only one eye. Since removal of the eye can cure most children research is now focused on preserving vision.
- Rhabdoid tumor of the kidney is a very rare type of kidney tumor, and rhabdoid tumors can occur in other places of the body, as well. Researchers have found a specific gene mutation that leads to rhabdoid tumors.
- Soft tissue sarcomas can be found anywhere in the body. Rhabdomyosarcoma is a tumor that arises in the muscle cells, and is the most common type in children under age ten. The other soft tissue tumors are rarer and tend to be found in adolescents. They include fibrosarcomas, synovial sarcomas, malignantperipheral nerve tumors, leiomyosarcoma, liposarcoma, and others even rarer. Some soft tissue tumors are similar to those found in adults, while others are very unique to children.
- Wilms Tumor accounts for about 90% of kidney tumors in children. About 95% of children with this tumor have a "favorable histology" (better cure rate with less treatment) as determined by the pattern the pathologist sees in the tumor cells. The other 5% have anaplastic Wilms tumor, which is much more resistant to treatment.
- Other Rare Childhood Cancers: There are many types that are so rare it is difficult to do research on them. However, "rare" is a relative term, as this account for about 15% of childhood cancers, jumping to 30% if adolescents are included. Rare childhood cancers include germ cell tumors, liver tumors (hepatoblastoma and hepatocellular carcinoma), adrenocortoco carcinoma, colon cancer, melanoma, nasalpharangyal cancer, thyroid tumors and others.
A number of studies are examining suspected or possible risk factors for childhood cancers, including early-life exposures to infectious agents; parental, fetal, or childhood exposures to environmental toxins such as pesticides, solvents, or other household chemicals; parental occupational exposures to radiation or chemicals; parental medical conditions during pregnancy or before conception; maternal diet during pregnancy; early postnatal feeding patterns and diet; and maternal reproductive history.
Treatment of Childhood cancer
Treating children is different from treating adults. Childhood cancer treatment involves many professionals other than nurses and doctors, too. Our hospital has psychologists, social workers, child life specialists, nutritionists, rehabilitation and physical therapists, and educators who can support and care for the entire family.
The treatment of cancer in children can include chemotherapy (the use of medical drugs to kill cancer cells), radiation (the use of radiant energy to kill cancer cells), and surgery (to remove cancerous cells or tumors). The type of treatment needed depends on the type and severity of cancer and the child's age.
Chemotherapy is medication which is used as a tool to eliminate cancer cells in the body. Kids with cancer can be given the chemotherapy medications intravenously (through a vein) or orally (by mouth). Some forms of chemotherapy can be given intrathecally, or into the spinal fluid. The drugs enter the bloodstream and work to kill cancer in all parts of the body.
The duration of chemotherapy treatment and type and number of different of drugs used depends on the type of cancer and the child's response to the drugs. Every child's treatment differs, so a child may receive daily, weekly, or monthly chemotherapy treatments. The doctor may also recommend cycles of treatment, which allow the body to rest and recover between periods of chemo.
Radiation is one of the most common treatments for cancer. A child who receives radiation therapy is treated with a stream of high-energy particles or waves that destroy or damage cancer cells. Many types of childhood cancer are treated with radiation along with chemotherapy or surgery.
For children with leukemia or lymphoma, surgery generally plays a minor role. This is because leukemia and lymphoma involve the circulatory system and lymphatics, two systems that are located all throughout the body, making it difficult to treat by operating on one specific area.
In children with solid tumors that haven't spread to other parts of the body, however, surgery can often effectively remove cancer when used in combination with chemotherapy and/or radiation.
Bone Marrow Transplants
Kids with certain types of cancer may receive bone marrow transplants. Bone marrow is a spongy tissue inside certain bones of the body that produces blood cells. If a child has a type of cancer that affects the function of blood cells, a bone marrow transplant (along with chemotherapy to kill the defective cells) may allow new, healthy cells to grow. Bone marrow transplant is also sometimes used to treat cancer that does not involve blood cells because it lets doctors to use higher doses of chemo than would otherwise be.