What is osteosarcoma?

Osteosarcoma is a cancer of the bone, typically found in the arms, legs or pelvis. Cancer can form in the bone or spread to the bone from another place in the body. Primary bone cancer is cancer that starts in the bone tissue. Secondary, or metastatic bone cancer, is when cancer spreads to the bone from another site in the body.

Other types of bone cancer include:

  • Ewing sarcoma — tumors that typically develop in the cavity of the leg and arm bones.
  • Chondrosarcoma — cancer of the cartilage.
  • Fibrosarcoma and malignant fibrous histiocytoma — cancers that develop in soft tissues, such as tendons, ligaments, fat and muscle, and then move to the leg, arm or jaw bones.
  • Giant cell tumor — a malignant primary bone tumor. Giant cell tumors are most commonly found in the arm or leg bones.
  • Chordoma — a primary bone tumor that usually occurs in the skull or the spine.

How common is osteosarcoma/bone cancer in children?

According to the American Cancer Society, bone cancers account for about 3 percent of childhood cancers. It's important to know that all cancers in children are considered rare, so the chances of a child developing bone cancer are also rare.

Bone cancers are more commonly found in older children and teenagers. The two main types of bone cancers that develop in children are osteosarcoma and Ewing sarcoma. Osteosarcoma tends to develop in areas where the bone is growing quickly, such as the leg or arm bones. Ewing sarcoma is most often found in young teens and tends to start in the pelvic or hip bones, the ribs or shoulder blades or the longer leg bones.

What are pediatric bone tumors? How common are they?

Pediatric bone tumors are abnormal growths of tissue in the body, which form when abnormal cells multiply and grow. Bone tumors are abnormal tissue growths that start in the leg, ribs or arm bones. Tumors that start in the leg muscles, tendons, fat or blood vessels are referred to as soft tissue tumors. Malignant bone and soft tissue tumors are called sarcomas.

Ewing sarcoma, a tumor that develops mainly in the bone or soft tissue, accounts for less than 3 percent of all childhood cancers. Ewing sarcoma typically develops in children and young adults ages 5 to 20.

While some adult cancers are linked to environmental or lifestyle factors, childhood cancers can develop due to DNA changes in cells early in a child's life, or even before their birth. The development of Ewing sarcoma is most often the result of a chromosome rearrangement between chromosomes #11 and #22. Some physicians classify Ewing sarcoma as a primitive neuroectodermal tumor (PNET), which means that the tumor may have started in fetal or embryonic tissue and developed into nerve tissue.

Osteosarcoma (or osteogenic sarcoma) typically occurs in long bones, such as the humerus arm bone, the femur and tibia in the legs or the pelvis. Osteosarcoma is most commonly found in children and young adults between the ages of 10 and 25. Osteosarcoma is also more common in boys than in girls and can spread to other areas of the body, such as the lungs.

The direct cause of Osteosarcoma is unclear. Doctors and scientists have determined that osteosarcoma is linked to other medical conditions. Inherited DNA mutations may also be a factor.

What are the symptoms of pediatric bone cancer?

Symptoms of osteosarcoma can appear weeks, or even months before a diagnosis is made. However, most osteosarcomas are found at an early stage, before cancer has spread to other parts of the body.

Common signs and symptoms of osteosarcoma include:

  • Pain and swelling in the affected bone (typically in the knee or upper arm)
  • Bone fractures (uncommon)
  • Decreased motion in the joints

Ewing sarcomas are typically found due to pain in the area of the body where the tumor is. Bone pain can be the result of the tumor spreading in the bone or a bone fracture due to the tumor weakening the bone.

Other symptoms of Ewing tumors are:

  • Lumps or swelling, most likely noticed in tumors in the arms or legs
  • Fever
  • Feeling tired or fatigued
  • Weight loss
  • Although rare, tumors near the spine can cause weakness, numbness or paralysis in the arms or legs
  • While also rare, tumors that have spread to the lungs can cause shortness of breath

It's not uncommon for bone cancers in children to be first diagnosed as something else. An active child who plays a lot of sports may have bumps or bruises on their legs or arms, but a doctor won't know that there's a potential tumor in the bone until symptoms get worse, or the bone tumor appears in an X-ray.

What kinds of treatments are there for pediatric bone tumors?

Treatment for osteosarcoma involves surgery and chemotherapy. After the cancerous tumor is completely removed, a patient undergoes chemotherapy, in order to kill any cancer cells that could develop, grow or spread. For localized osteosarcoma (which has not spread to other parts of the body), the long-term survival rate for patients with this type of bone cancer is roughly 70 percent.

For Ewing sarcomas, the first form of treatment that most patients undergo is chemotherapy. Surgery to remove the tumor is typically the next stage of treatment. For pediatric bone tumors, like Ewing sarcomas, radiation may be used in conjunction with surgery, or instead of surgery if it would be difficult to remove the entire tumor. Another round of chemotherapy typically follows surgery or radiation.

Pediatric cancer clinics that treat childhood bone tumors

For children with bone cancer or a bone tumor, most are treated at a pediatric cancer clinic. Pediatric bone cancers are a specialized field, requiring the care and attention of a large team that includes pediatric oncologists, surgeons, nurses, physician assistants and support staff. Pediatric cancer clinics are focused solely on treating children and adolescents, as childhood cancers are different than cancers that develop in adults.

Rocky Mountain Hospital for Children (RMHC) is a leader in treating and providing high-quality care for child and teenage cancer patients. Our pediatric cancer clinic offers a warm and inviting environment for patients undergoing cancer treatments. Child Life Specialists are on hand to assist patients and their families during each stage of the treatment process, which can be difficult at times. At RMHC, patients receive treatment in a home-like atmosphere designed to make young children and adolescents feel comfortable and cared for.

To learn more about pediatric bone cancers and other types of cancers that can develop in children, talk to your child's doctor or pediatrician.