Diagnosis & Staging
There are 206 bones in the human body. They give the body structure and protection. Bone sarcomas can develop in any bone in the body but are most common in the leg and arm bones.
Cancer that has spread to the bone from another part of the body is called secondary bone cancer. For more information, see Bone Secondary.
Diagnosing bone sarcomas is difficult because the symptoms are similar to those for bone injuries, bursitis (inflammation of fluid-filled sacs called bursae), arthritis (inflammation of joints) and non-cancerous bone tumours.
Symptoms will be different depending on the type of sarcoma and where it is in the body.
Bone sarcoma symptoms can include:
- Pain in bone or joint.
- Bone fractures (cancerous tumours can make bones weak).
If you have any signs or symptoms that you are worried about, please talk to your family doctor or nurse practitioner.
Tests that may help diagnose bone sarcoma include:
- Physical exam
- X-ray: to help find the tumour.
- Chest X-ray: to see if cancer has spread to the lungs
- CT (computed tomography) scan: to show the tumour in more detail and to check if cancer has spread to your lungs.
- MRI (Magnetic Resonance Imaging): to show the tumour in more detail.
- Biopsy: a small amount of tissue from the tumour is removed so that a specialist (pathologist) can examine it under the microscope and see if it is cancer.
- Bone scan: to show the tumour and see if cancer has spread.
For more information on tests used to diagnose cancer: BC Cancer Library screening and diagnosis pathfinder.
Bone sarcomas are named after the tissue type they most look like.
- Most common.
- Often develops in the growing ends of the long bones of the arms and legs, such as at the knees or shoulders.
- Most commonly found in adolescents (children who are about 10-19 years old). May be related to growth spurts.
- Slightly more common in males than females. [See note below, Statistics]
- Can also affect older adults.
- Can spread to the lungs and other parts of the body through the bloodstream.
- Does not usually spread to the lymph nodes.
- Grows in cells that make cartilage.
- Most often found in older adults.
- Most common symptoms are bone swelling and pain.
- Tumours that develop in the bone or soft tissue.
- Ewing tumour of the bone is a specific type of Ewing's sarcoma.
- Very aggressive.
- Grows at the end of the spinal cord or near the base of the skull.
- Pain near the end of the spinal cord is a common symptom for tumours in that area.
- Tumours growing at the base of the skull may affect the cranial nerves. Most commonly, this can affect your vision.
- Symptoms may last for many months before a diagnosis.
- Grow very slowly.
Malignant Fibrous Histiocytoma (MFH) of the bone
- Can sometimes grow from an osteosarcoma.
Peripheral Neuroectodermal Tumour (PNET)
- More common in children.
- Same genetic change as Ewing's sarcoma of the bone.
Staging describes the cancer. Staging is based on how much cancer is in the body, where it was first diagnosed, if the cancer has spread and where it has spread to.
The stage of the cancer can help your health care team plan your treatment. It can also tell them how your cancer might respond to treatment and the chance that your cancer may come back (recur).
The grade of bone cancer describes how the tumour cells look under the microscope:
- G1: Low grade. The tumour looks more like normal bone.
- G2: Intermediate grade – treated as high grade
- G3: High grade. The tumour looks very different from normal bone.
- Stage 1A: Tumour is 8 cm or smaller and low grade.
- Stage 1B: Tumour is larger than 8 cm or there are tumours in many parts of the same bone (discontinuous tumours). Low grade.
- Stage 2A: Tumour is 8 cm or smaller and high grade.
- Stage 2B: Tumour is larger than 8 cm and high grade.
- Stage 3: Tumours in many parts of the same bone and high grade.
- Stage 4: Cancer has spread to other parts of the body such as the lungs, brain other bones or lymph nodes. Metastatic bone cancer. Can be low or high grade.