Metastatic bone tumours
Metastases are the most common bone tumours in older patients. They will present to the orthopaedic surgeon with pain, either because of an actual or threatened pathological fracture, or will present with a lytic or sclerotic bone lesion. The patient may have had a primary diagnosed years beforehand, and a history of previous surgery or investigations must be extracted as such information is not always volunteered.
Q: When does a patient with a known metastasis require prophylactic fixation?
Once a pathological bone has fractured conservative treatment will fail and the bone needs ORIF. After fixation all the bone needs radiotherapy to kill residual cancer cells.
A more accurate system of scoring secondary tumors for the risk of pathological fracture is the method of Mirels. Points are scored for site, position and whether the tumor is lytic or blastic. If the score is >7 the tumour needs ORIF.
Occult tumorsAn occult metastasis obvious on X-ray but there is no primary on physical examination. Common causes are primaries in the lung, thyroid and kidneys. Special investigations such as chest X-ray, thyroid scan and abdominal sonar are required. In metastatic disease a technetium scan is required to see other skeletal mets. and judge the prognosis.
Treatment of secondary tumors is basically palliative. Fixation is done using he above guidelines and about 10 days later radiotherapy is given to the limb. Attention is also directed at the primary and hormonal or chemotherapy given as required.
Spinal metastases with neurological fallout are sometimes amenable to surgical decompression and stabilisation. In vertebral metastases due to a high grade tumor and a poor general prognosis radiotherapy alone is recommended.