Osteosarcoma is a type of bone cancer.

Bone cancers can be divided into two main groups: primary and secondary. Primary bone cancers are tumours which start in the bones, secondary bone cancers are tumours which are made up of seedlings of cancer which have come from tumours elsewhere in the body and spread to the bones.

Secondary bone cancers are very common whereas primary bone cancers are very uncommon. There are only about 600 new primary bone cancers diagnosed in the UK each year and they make up less than 1% of all cancers.

There are several different types of primary bone cancer and osteosarcoma is the commonest of these.

Osteosarcomas are most often seen in children, adolescents and young adults. They can occur later in life but this is usually as a very uncommon complication of a pre-existing bone disease, such as Paget's disease of the bone.

Osteosarcomas usually develop in the long bones of the leg or arm. About half of all these cancers involve the area around the knee joint and another quarter affect the bone of the upper arm (the humerus).

Osteosarcomas usually first appear as swellings on the bone which are often painful.

They are usually quite aggressive cancers with a strong tendency to spread to the lungs.

In the past treatment was based on amputation of the affected limb. Over the last twenty years, however, the approach has changed dramatically. Improvements in surgery mean that very often the cancer can be removed without the need for amputation. Combining these new surgical techniques with intensive chemotherapy has led to a great improvement in the outlook for people with osteosarcoma. In the past less than 1 in 5 people were cured but now the majority can expect to be long-term survivors.