Cancer describes a disease characterized by the formation of an invasive tumor due to the abnormal and out-of-control growth of cells. Cancer can affect any type of cell in the body, including those cells found in the bones. Most tumors on the bone are benign, meaning they do not invade other tissues in the body. Primary bone cancer, that which begins in the bones, remains rare, with only 2,000 new cases diagnosed each year in the United States, according to the University of Maryland Medical Center.
Cancer Classifications
Two main types of bone cancer exist; multiple myeloma and sarcoma. Multiple myeloma begins in the specialized white cells found in bone marrow known as plasma cells. Plasma cells make proteins that help to fight infections. In multiple myeloma, the abnormal plasma cells make abnormal proteins that can affect the bones, kidneys, immune system and number of red blood cells. Sarcoma describes a group of cancers that can begin in soft tissues such as muscles, fat, nerves or connective tissues or bones.
Sarcoma Types
Doctors classify sarcoma bone cancers based on the tissues they originate in. Osteosarcoma, the most common form, begins in cells in the bone. Osteosarcoma accounts for approximately 35 percent of all bone tumors, according to the Abramson Cancer Center at the University of Pennsylvania. Chondrosarcoma, the second-most common type of sarcoma, originates in the cartilage---the tissue that connects bones together. Ewing's sarcoma usually arises from bone tissue, but may begin in the soft tissue surrounding the bone.
Location
Osteosarcome can affect any bone, but most commonly occurs around the knee, with the hip and shoulder sometimes affected, according to the American Academy of Orthopaedic Surgeons. Ewing sarcoma, the most common type of bone cancer in children, occurs in the lower leg, pelvis, upper arm or rib bones. Doctors diagnose most cases of chondrosarcoma around the hip, pelvis or shoulder.
Risk Factors
Although doctors do not know what exactly causes primary bone cancer, the presence of some factors can increase the risk of developing bone cancer. Patients exposed to radiation, such as those treated for another type of cancer, may suffer from damage to cells in the bone that can develop into bone cancer. As with most forms of cancer, mutations in the genetic material known as deoxyribose nucleic acid, can lead to cell damage and the development of cancer. The doctors at MayoClinic.com report that patients with multiple myeloma all exhibit genetic abnormalities in the plasma cells. Other risk factors include age, race and obesity.
Symptoms
Cancer in the bone may be difficult to detect, as the tumors may not produce any noticeable symptoms. Some people may experience bone pain often described as dull and achy. Others feel tenderness or swelling in a joint or suffer from fractures as the tumor weakens the bone. Multiple myeloma can cause a decrease in red blood cells, leading to fatigue, anemia and weight loss.
