Prosthetic replacement for metastasis

Replacement is preferred when the bone is so destroyed that a fixation would have nothing to anchor to, when the lesion sits right at a joint (for example, the hip or the shoulder), or when a definitive one-operation solution is the goal.

Before resecting and replacing a segment of bone it is essential to confirm that the lesion is a metastasis and not a primary bone tumor: the oncologic history is reviewed and, when there is any doubt, a biopsy is taken. When there is no known cancer, staging is completed before the biopsy —blood tests and imaging of the chest, abdomen and pelvis, plus a whole-body bone study—, which in most cases identifies the tumor of origin and avoids operating on a mislabeled lesion. A resection planned for a metastasis does not aim for the wide margins a bone sarcoma requires, so operating on an undiagnosed sarcoma by mistake can seriously compromise its later treatment.

In a solitary metastasis from a kidney or thyroid primary —tumors that respond poorly to radiotherapy and are often highly vascular— en bloc resection and replacement of the segment may be considered, rather than fixation alone. In highly vascular renal lesions a pre-operative embolization is usually done to reduce bleeding.

The involved bone is resected and reconstructed with a prosthesis, often a megaprosthesis (tumor prosthesis) similar to the one used after a sarcoma resection. The prosthesis provides immediate stability, allowing early weight-bearing and movement —a central goal when quality of life is the priority.

Treatment is coordinated with oncology and, depending on the case, radiotherapy. The goal is the best possible quality of life: controlling pain, maintaining function and avoiding reoperations in someone who is being treated for their cancer.

The decision to operate is made together with you and your oncology team: we discuss your symptoms, the fracture risk, the point your illness has reached and your other treatments (such as radiotherapy), the expected benefits, the risks and the alternatives. Surgery does not guarantee an outcome or cure the underlying disease; it aims to relieve pain and restore stability and function and, in selected cases, achieve local control of the lesion.