Bone cancer is a cancer that starts in the bone. It is a very rare cancer. The cancer that spreads from another part of the body into surrounding bone is known as secondary bone cancer.
Bones are made of cells bound together by a calcium-like material. This makes them strong and rigid. Bones are hollow, filled with a spongy bone marrow, which makes blood cells. The human body has more than 200 bones. Their functions are to support the body (long bones), protect parts of the body (rib cage and skull bones), and act as levers and allow us to move (tendons and cartilage of the bones).
There are four most common types of bone cancer:
- Osteosarcoma – the most common type of bone cancer; it develops mostly in teenagers and young adults, although it can develop at any age; it usually develops in the larger bones such as the thigh bone or the shin bone
- Ewing's sarcoma is most common in teenagers; it usually develops in the pelvis, thigh bone or shin bone.
- Chondrosarcoma usually develops in adults, between 30 and 60; it mostly affects the pelvis, thigh bone, upper arm bone, shoulder blade and the ribs
- Spindle cell sarcoma develops in persons over 40; it is very similar to osteosarcoma
The symptoms of bone cancer vary, depending on the size of the cancer and location. The symptoms are:
- Pain around the bone tumour
- Swelling (may show when the tumour is larger)
- Problems with movement, if the cancer is near a joint
- Broken bone (rarely)
- Weight loss
Other less common symptoms that you may have with bone cancer include:
- Fever or sweats
The cause of primary bone cancer is not known. It is known that cancer begins with a change in the DNA structure. This change in the DNA structure is known as a mutation, and it can alter the instructions that control cell growth. This means that cells continue to grow instead of dying (called, apoptosis) when they should. This causes cells to reproduce uncontrollably, producing a lump of tissue called a tumour.
The factors that increase the risk of developing bone cancer are few, considering the unknown cause of it. The risk factors are:
- Fast-growing bones – the majority of cases of bone cancer develop in teenagers and therefore this is considered as a risk factor; this has been seen in certain breeds of dogs with bone cancer
- Previous radiation therapy
- Paget’s disease of bones, which affects older people
- Rare genetic conditions, such as Li-Fraumeni syndrome
- Retinoblastoma (cancer in the eye in children)
Research has also found that babies born with an umbilical hernia are three times more likely to develop Ewing’s sarcoma than others.