Bone Cancer - Sarcoma
A sarcoma is a bone cancer that contains cancer (malignant) cells. A benign bone cancer
is an abnormal growth of noncancerous cells.
General information about Bone Cancer
A primary bone cancer originates in or near a bone. Most primary bone cancers are
benign, and the cells that compose them do not spread (metastasize) to nearby tissue or to
other parts of the body.
Malignant primary bone cancers account for fewer than one percent of all cancers
diagnosed in the United States. They can infiltrate nearby tissues, enter the bloodstream,
and metastasize to bones, tissues, and organs far from the original malignancy. Malignant
primary bone cancers are characterized as either:
- Bone cancers which originate in the hard material of the bone.
- Soft-tissue sarcomas which begin in blood vessels, nerves, or tissues containing
muscles, fat, or fiber.
Types of bone cancers
Osteogenic sarcoma, or osteosarcoma,
is the most common form of bone cancer, accounts for six percent of all instances of the
disease, and for about five percent of all cancers that occur in children. Nine hundred
new cases of osteosarcoma are diagnosed in the United States every year. The disease
usually affects teenagers, and is almost twice as common in boys as in girls.
Osteosarcomas, which grow very rapidly, can develop in any bone but most often occur
along the edge or on the end of one of the fast-growing long bones that support the arms
and legs. About 80% of all osteosarcomas develop in the parts of the upper and lower leg
nearest the knee (the distal femur or in the proximal tibia). The next likely location for
an osteosarcoma is the bone of the upper arm closest to the shoulder (the proximal
humerus).
Ewing's sarcoma is the second most common form of childhood bone cancer. Accounting for
fewer than five percent of bone cancers in children, Ewing's sarcoma usually begins in the
soft tissue (the marrow) inside bones of the leg, hips, ribs, and arms. It rapidly
infiltrates the lungs, and may metastasize to bones in other parts of the body.
More than 80% of patients who have Ewing's sarcoma are white, and the disease most
frequently affects children between ages 5-9, and young adults between ages 20-30. About
27% of all cases of Ewing's sarcoma occur in children under age 10, and 64% occur in
adolescents between ages 10-20.
Chondrosarcomas are cancerous bone cancers that most often appear in middle age.
Usually originating in strong connective tissue (cartilage) in ribs or leg or hip bones,
chondrosarcomas grow slowly. They rarely spread to the lungs. It takes years for a
chondrosarcoma to metastasize to other parts of the body, and some of these cancers never
spread.
Parosteal osteogenic sarcomas, fibrosarcomas, and chordomas are rare. Parosteal
osteosarcomas generally involve both the bone and the membrane that covers it.
Fibrosarcomas originate in the ends of the bones in the arm or leg, and then spread to
soft tissue. Chordomas develop on the skull or spinal cord.
Osteochondromas, which usually develop between age 10-20, are the most common
noncancerous primary bone cancers. Giant cell cancers generally develop in a section of
the thigh bone near the knee. Giant cell cancers are originally benign but sometimes
become malignant. |