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A 47-year-old woman presents to a local hospital emergency department (ED) with severe right hip pain after experiencing a standing-height fall at home. She describes taking a few steps off her front porch and her right leg collapsed underneath her. She was unable to bear weight and was brought by ambulance to the ED. Radiographic examination of the right lower extremity reveals a pathologic subtrochanteric femur fracture. The patient was diagnosed with small cell lung cancer in the right upper lobe 6 months ago and is currently undergoing chemotherapy treatments. Positron emission tomography (PET)/computed tomography (CT) scan obtained one month ago revealed invasion into the mediastinum and right paravertebral area. Subsequent magnetic resonance imaging showed abnormal signal at T3 that was thought to be related to direct extension of the disease. You are called to evaluate the patient in the ED. Which choice is the next best step in treating this patient?
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The primary source of metastatic lesions should be identified and agreed upon by the patient’s team of healthcare providers prior to surgical fixation. This team often includes a radiologist familiar with identifying bony lesions, the patient’s oncologist (who may have already identified the primary source), and the orthopedic surgeon who may obtain a biopsy for frozen section prior to fixation. In most cases of suspected metastatic disease, open biopsy with intraoperative frozen section is performed to confirm the primary source. A definitive diagnosis should be made prior to proceeding with fixation in order to avoid potential spread of an unknown primary malignant bone lesion. However, patients with advanced breast, lung, or prostate cancer that has spread to other organs do not require further work-up of a new bone lesion, including a confirmatory biopsy, prior to fixation. One exception to this is that any new lesion in an area previously treated with radiation therapy should be biopsied to rule out radiation-induced sarcoma. A preoperative percutaneous core needle biopsy is recommended if a malignant sarcoma is suspected.
Resection and endoprosthetic reconstruction is the treatment of choice for pathologic fractures of the femoral neck. Total hip arthroplasty is recommended if the acetabulum is involved. Hemiarthroplasty is more stable than total hip arthroplasty and can be used for isolated femoral neck fractures. Subtrochanteric and femoral shaft fractures, and impending fractures, should be treated with a long intramedullary nail that spans the length of the femur.
External beam radiation therapy is performed postoperatively once the wound heals to decrease pain and minimize disease progression. Postoperative radiation exposure has no effect on callus formation and healing rates. Tumors that are radiosensitive or respond to lower doses of radiation include myeloma, lymphoma, breast, and prostate carcinomas. Lung and thyroid carcinomas, along with melanoma, have intermediate responsiveness to radiation therapy. Renal cell carcinomas and sarcomas are the least responsive and require higher doses of radiation.
Use of bisphosphonates postoperatively inhibits growth of tumor cells, decreases metastatic spread, provides pain relief, and decreases recurrent fracture rates. Bisphosphonates also help treat hypercalcemia associated with bone destruction from the malignancy.
References
- Quinn RW, Randall RL, Benvenia J, Berven SH, Raskin KA. Contemporary management of metastatic bone disease: tips and tools of the trade for general practitioners. J Bone Joint Surg Am. 2013;95(20):1887-1895.
- O’Donnell P. Metastatic cancer of bone. http://www.orthobullets.com/pathology/8045/metastatic-cancer-of-bone. Accessed July 14, 2015.
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