Your Health A-Z

Osteosarcoma

This is a malignant bone tumour. Though rare, it is the most common type of primary bone cancer (marrow cancers are more common), and occurs mainly in adolescents and young adults.

Definition and incidence

Also known as osteosarcoma, this is a malignant bone tumour. Though rare, it is the most common type of primary bone cancer (marrow cancers are more common), and occurs mainly in adolescents and young adults. The most common site is around the knee, but any bone may be affected. Some cases occur on older persons, associated with Paget’s disease, or irradiation.

Causes and risk factors

There is no known definite cause, though there is a familial tendency, and a genetic link has been suggested. There are no known predisposing risk factors.

Diagnosis

The patient usually sees a doctor because of

  • pain,
  • tenderness to touch and
  • swelling of the bone, or
  • limitation of movement.
  • Sometimes the first sign is an unexpected fracture in an otherwise healthy young person.

The external appearance of the affected area is not diagnostic, so special investigations must be done.

Tests

X-ray of the affected are is mandatory, as valuable time may be lost with a wrong diagnosis and inappropriate treatment. X-ray appearance suggesting osteosarcoma is followed by scans, either CT, PET or MRI; and may proceed to a biopsy done by an experienced orthopaedic surgeon to determine cell type. This decision is made by a panel (see Management).

The site, size and spread of the tumour will affect the choice of treatment, and the likely outcome.

Management

Osteosarcoma is jointly managed by experienced medical and orthopaedic oncologists.

This tumour is generally resistant to irradiation, but chemotherapy may be used, especially to shrink the tumour, and deal with any spread to distant sites (metastases), such as to the lungs. This then may permit limb-sparing surgery, and avoid amputation. Reconstructive surgery may be considered in the hands of an experienced orthopaedic surgeon, and may involve repeated surgery for prostheses and tendon re-implantation.

In some cases, limb-sparing surgery may not be possible. In others, whilst some form of surgery might be possible, it may be too debilitating. In these cases, some form of radiation may be considered, especially if biopsy has shown a particular cell type.

Complications of the disease and side effects of treatment, like wound infection, pain and nausea, will also need managing.

Outcome

This will depend largely on the stage of the disease when first diagnosed, the skills and experience of the medical team involved, and the adequacy of the treatment regime chosen.

  • On average, early limited disease, well treated, can have a more than 90 percent five-year survival rate.
  • For large aggressive tumours with early multiple metastases, this may drop to 50 percent.

No definite prognosis can be given, as each patient responds differently to treatment.

(Dr AG Hall)

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