Most of the skeleton is composed of bone which forms a rigid frame work bearing the weight of the body. A malignant tumour which develops in the skeleton is known as bone cancer.

There are two main classes of cancer: the carcinomas which develop in the lining and covering tissue of organs, and the sarcomas which develop in the connective and supportive tissues of the body. Bone cancers are usually sarcomas. Most common childhood bone tumours are osteogenic sarcomas which appear usually in the bones around the knee. Ewing’s sarcoma, also a children’s cancer, usually affects the mid shaft of bones. These childhood cancers will be discussed in the next chapter.

Bone cancer in adults is usually secondary to a primary tumour elsewhere in the body, which has spread to the site via the bloodstream. On rare occasions cancer can extend to the bone from adjacent tissues. Secondary bone cancers are much more common than cancer which starts in the bone and they usually originate in the breast, lung, thyroid and kidneys. The areas usually affected by the secondary growth are the spine, the ribs, the pelvis, the skull and the upper thighs.

Symptoms

Unlike cancer at other sites, pain is the symptom most noticeable in bone cancer probably because of the rigidity of bony tissues which cannot expand when pressed on by an invading tumour. The pain from bone cancer is usually worse at night. The most frequent sites are the thigh, knee, pelvis, upper arm, ribs and vertebrae. Swelling or fever may accompany the ache and if it affects the lower limbs there may be repeated unexplained stumbling.

Primary bone cancer mostly affects children and early symptoms are usually dismissed as either a sprain or growing pains. In older patients, who have already learned to live with aches and pains, cancer of the bone is frequently discovered only when a tumour-weakened bone fractures.

Treatment

Treatment of bone cancer can involve all three interdependent approaches of cancer-control surgery, radiotherapy and drugs. In the case of osteogenic carcinoma, amputation of the limb at least eight centimetres above the point where X-rays show cancerous cells is usually recommended. Present day amputees usually return to normal ability very quickly, being fitted with a light-weight prosthesis or artificial limb, in many cases held on by suction.

Both chemotherapy and radiotherapy may be used along with surgery. Some patients with osteogenetic sarcomas may be treated with high doses of special anti-cancer drugs which cause hair loss, nausea and vomiting, as well as inflammation of the lining of the mouth. The course of drug treatment may take anything up to two years. After treatment medical examinations are carried out regularly to monitor for a recurrence of the disease.