What is bone cancer?

Bone cancer starts in the cells of the bone or cartilage. It is also called primary bone cancer. A cancerous (malignant) tumour is a group of cancer cells that can grow into and destroy nearby tissue. It can also spread (metastasize) to other parts of the body. Primary bone cancer is very rare in adults over the age of 40. It is more common in children, adolescents and young adults.

Other types of cancer can spread to the bone, but they are not the same disease as primary bone cancer. Cancer that starts in another part of the body and spreads to the bone is called bone metastasis or secondary bone cancer. This is much more common than primary bone cancer. Find out more about bone metastasis.

Types of bone tumours

Bone or cartilage cells sometimes change and no longer grow or behave normally. These changes may lead to non-cancerous (benign) conditions such as bone cysts. They can also lead to non-cancerous tumours such as osteochondroma, osteoma and osteoclastoma (also called giant cell tumours of bone).

But in some cases, changes to bone or cartilage cells can cause bone cancer.

The most common types of cancerous bone tumours found in adults over the age of 30 are chondrosarcoma and osteosarcoma. These tumours are most often found in the legs or arms. Chordoma is another cancerous tumour that can start in the bones of the skull or spine.

Rare types of bone cancer can also develop. These include fibrosarcoma, angiosarcoma and undifferentiated high-grade pleomorphic sarcoma. Ewing sarcoma is much more common in children and young adults than in older adults.

The bones

The adult human skeleton is made up of 206 bones. Together, groups of bones and cartilage form the skeleton, which gives shape and form to the body.

Diagram of the human skeleton
Diagram of the human skeleton

Bone cells

There are 3 types of cells that make up bones:

  • Osteoblasts build new bone.
  • Osteoclasts dissolve and remove old bone.
  • Osteocytes carry nutrients from the blood to the bone and move waste products away from the bone.

Bone is a very active tissue. Bone tissue is constantly being replaced by new bone tissue (remodelled). Some hormones, minerals and bone cells have a role in the process of bone remodelling. Bones respond to changes in the blood’s calcium levels and the pull of gravity and muscles on the skeleton.

Types of bone

Bones may be classified based on their shape.

Long bones are longer than they are wide. They usually have a shaft with heads at both ends. They are mostly made up of compact bone. Examples of long bones are thigh and arm bones.

Short bones are often smaller cube-shaped bones. They contain mostly spongy bone. Examples of short bones include wrist and ankle bones.

Flat bones are thin, flat and are often curved. They have 2 thin layers of compact bone with a layer of spongy bone between them. Examples of flat bones are the ribs or the breast bone.

Irregular bones have complex shapes and can’t be classified into the above categories. Examples of irregular bones include the pelvic bones and the vertebrae of the spine.


Bone is one of the hardest materials in the body. It is made of collagen and minerals, such as calcium, that make it strong and hard. Although bones differ in shape and size, they have basically the same structure and function.

Bone is made up of different layers of materials. Several terms are used to describe features of bones throughout the body.


The periosteum is a layer of fibrous tissue that covers the bone, except at the ends.

Compact bone

Compact bone is the dense, hard, smooth outer layer of bone. Compact bone surrounds the yellow bone marrow in the shaft of the bone and supports the hollow part of the bone.

Compact bone has many canals (passageways) that contain blood vessels and nerves. Blood vessels carry the blood to bone cells. The blood brings oxygen and nutrients to the bone cells. It also takes away carbon dioxide and waste products. Nerves are in the bone and around the bone.

Medullary cavity

The medullary cavity is the space inside the shaft that contains yellow bone marrow. The yellow bone marrow mainly stores fatty tissue.

Spongy bone

Spongy (cancellous or trabecular) bone is made up of small pieces of bone and lots of open space, sort of like a honeycomb. Spongy bone stores the red bone marrow where blood cells are made. In an adult, red marrow is found mainly in the spongy bone in the skull, breastbone (sternum), ribs, pelvic bones, collar bone (clavicle) and spinal bones (vertebrae).


Cartilage covers the ends of the bones. It is a tough, fibrous connective tissue mixed with a gel-like substance. It is softer than bone but firmer than most tissues. Cartilage stops the bones from rubbing together and acts like a cushion to absorb shock.

The long bones

Cancer is more likely to start in the long bones of the body.

Long bones have 4 main parts:


The shaft (diaphysis) of a long bone makes up most of the bone’s length.

The metaphysis is the part of a long bone next to the diaphysis.


The epiphysis is the end of the long bone. It is made up of compact and spongy bone tissue. Long bones have an epiphysis at each end.

The growth (epiphyseal) plate between the metaphysis and the epiphysis is a layer of cartilage that allows the bones to grow. This disappears by the age of 20.

What the bones do

Bones do many things, including:

  • give the body its shape and support the body’s tissues
  • protect important organs, such as the heart, lungs and brain
  • work with muscles, tendons and ligaments to allow the body to move
  • store fat and minerals and release minerals, such as calcium, phosphorus and magnesium, when they are needed by the body
  • make blood cells in the red bone marrow of certain bones

Expert review and references

  • American Cancer Society. Bone Cancer. 2016.
  • Cancer Research UK. Types of bone cancer. Cancer Research UK; 2013.
  • Hakim DN, Pelly T, Kulendran M, Caris JA . Benign tumours of the bone: a review. Journal of Bone Oncology. 2015.
  • Macmillan Cancer Support. Understanding Primary Bone Cancer. Macmillan Cancer Support; 2014.
  • Martini FH, Timmons MJ, Tallitsch RB. Human Anatomy. 7th ed. San Francisco: Pearson Benjamin Cummings; 2012.
  • O'Donnell RJ, Dubois SC, Hass-Kogan DA . Sarcomas of bone. DeVita VT Jr, Lawrence TS, Rosenberg SA. Cancer: Principles and Practice of Oncology. 10th ed. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins; 2015: 91:1292–1313.
  • Samuel LC . Bone and soft-tissue sarcoma. Yarbro CH, Wujcik D, Holmes Gobel B (eds.). Cancer Nursing: Principles and Practice. 8th ed. Burlington, MA: Jones and Bartlett Learning; 2018: 46:1243-1277.

Cancerous tumours of the bone

Malignant tumours of the bone are cancerous growths that have the potential to spread (metastasize) to other parts of the body. Most bone cancers are called sarcomas.

Non-cancerous tumours of the bone

A benign tumour of the bone is a non-cancerous growth that does not spread (metastasize) to other parts of the body and is not usually life-threatening. Benign bone tumours are quite common, but the exact cause of most types is unknown.

Non-cancerous conditions of the bone

Benign conditions of the bone are non-cancerous diseases or abnormalities that do not spread (metastasize) to other parts of the body and are not usually life-threatening. Signs and symptoms of a benign bone condition are similar to those for a malignant bone tumour and may include a change in mobility.

Medical disclaimer

The information that the Canadian Cancer Society provides does not replace your relationship with your doctor. The information is for your general use, so be sure to talk to a qualified healthcare professional before making medical decisions or if you have questions about your health.

We do our best to make sure that the information we provide is accurate and reliable but cannot guarantee that it is error-free or complete.

The Canadian Cancer Society is not responsible for the quality of the information or services provided by other organizations and mentioned on cancer.ca, nor do we endorse any service, product, treatment or therapy.

1-888-939-3333 | cancer.ca | © 2024 Canadian Cancer Society