What is bone cancer?

The bones

The skeleton

There are more than 200 bones in the human body. Together they form the skeleton. The bones:

• support the body

• protect parts of the body

• act as levers for the muscles so we can stand and move

The long bones of the arms and legs are supporting bones. The bones of the rib cage protect the organs of the chest such as the lungs and heart. The skull bones protect the brain.

The end of every long bone is covered with a smooth tissue called cartilage. Tendons hold the long bones together where they join.

Together, cartilage and tendons form joints that allow the bones to move smoothly against each other.

The bone cells

Bone is a framework of soft supporting tissue called connective tissue. It also contains minerals such as calcium which hardens the bones. This framework gives the bone its strength. Throughout this framework are the bone cells. 

There are 3 main types of cells in our bones which work together to maintain the shape, strength and health of the bones. These are the:

• osteoblasts

• osteoclasts

• osteocytes

If a bone gets damaged, the osteoblasts make new bone to repair the damage.

The osteoclasts break down any extra bone framework that the osteoblasts make and reshape the bone.

When bone forms, osteoblasts are trapped within it and become part of the framework. They are then called osteocytes and maintain the bone structure.

Inside some of the bones of the body is a space that is filled with ​bone marrow. Blood cells are made in the bone marrow. All blood cells develop from ​stem cells​ which are found in the bone marrow.

Where does bone cancer start?

Primary bone cancer starts in cells of the bones. Doctors sometimes use the term bone sarcoma when they talk about primary bone cancer. Sarcomas are cancers that start in any connective tissue in the body. This includes the bones but also:

• muscles

• tendons

• blood vessels

• fatty tissues

There are several different types of primary bone cancer. The most common types are:

• osteosarcoma - is more common in the upper arms or legs (usually around the knee)

• chondrosarcoma - is mostly found in the long bones such as the fibula, femur, tibia, humerus, radius and ulna. Other sites include ​pelvis, shoulder blades, or ribs

• Ewing sarcoma - often starts in the pelvis, long bones, ribs or vertebrae (bones that protect the ​spinal cord​ and make up the spinal column)

Other rarer types include:

• spindle cell sarcoma - is more common in the bones of the legs

• chordoma - most commonly starts in the bone at the bottom of the spine (sacrum), the bones (vertebrae) of the back (spine), or the bones in the base of the skull

Read more about different types of bone cancer

Myeloma

A type of cancer called myeloma can affect the bones. People sometimes call it bone cancer. It develops from cells in the bone marrow called plasma cells. But it is not a type of primary bone cancer because it does not start in the bone itself. So if you have myeloma, your treatment will be different.

Read more about myeloma

Where does bone cancer spread?

When a primary bone cancer starts to grow, the cancer cells multiply and begin to break down the bone. This weakens the bone in that area.

Bone cancer cells can break away from the primary bone tumour and travel to other organs, usually the lungs or other bones. There they can grow into secondary tumours.

Who gets bone cancer?

Bone sarcoma is linked to age. Unusually for cancer, it is more common in older children and teenagers. And then it becomes more common again in older people. 

Read about the risks and causes of bone cancer

How common is bone cancer?

Around 610 people are diagnosed each year in the UK with bone cancer. That’s more than 1 case diagnosed every day.