Every year, more than 2000 people in the US are diagnosed with bone cancer. Bone cancer is a cancer that can affect any bone in the body, but is most commonly found in the long bones such as those in arms and legs. When cancer occurs in the bones, most of the time it is because it has spread from a cancer elsewhere in the body. This type of cancer is known as metastases or secondary cancer. True bone cancer is much less common, and it's important to determine whether the cancer comes from another site in the body or if it is a cancer of the bone cells themselves. This is because treatment for metastases is usually based on the primary cancer rather than the bone cancer.Bone cancer is caused when the cells that make up bone grow out of control, dividing irregularly and becoming abnormal. There are five most commonly found primary bone cancers, and, in order of occurrence, they are osteosarcoma, Ewing's sarcoma, chondrosarcoma, malignant fibrous histiocytoma (MFH), fibrosarcoma, and chordoma.Signs and SymptomsThe most common symptom of bone cancer is pain around the affected area. Depending on the type of tumor, and how fast it grows, it is sometimes months or even years after the pain starts before medical help is sought.Other than pain in the bone itself, people with bone cancer can suffer from nerve pain caused by the tumor pressing on the surrounding nerves, causing numbness or tingling, like pins and needles, in the arms or legs.Another symptom that affects the extremities is when the tumor presses on surrounding blood vessels. This may reduce the blood flow to the arm or leg, causing numbness, aching, and cold hands or feet.In some cases, particularly with fibrosarcoma and MFH, a mass or lump can be felt either on the affected bone itself, or in the surrounding tissue.Less common symptoms include weight loss, nausea, and night sweats. These particular symptoms are normally experienced if the bone cancer has spread to other parts of the body.