Skeletal Metastases Synopsis Demonstrates Suggested Decision Making for Surgeons

According to the American Cancer Society, an estimated 1.7 million Americans were diagnosed with cancer in the United States in 2018 and more than 15.5 million Americans were alive on Jan. 1, 2016, with a current or previous cancer diagnosis. Between 10 percent and 30 percent of patients with cancer will experience a pathologic fracture associated with metastatic disease. The proper management of a pathologic fracture through a metastatic lesion is not one-size-fits-all and, in many situations, necessitates a referral to an orthopaedic oncologist for optimal care.

A patient older than 40 years of age who presents with a pathologic fracture without a known cancer diagnosis requires an initial workup, including standard laboratory tests (complete blood count, comprehensive metabolic panel, alkaline phosphatase, and protein electrophoresis); chest radiographs (anterior/posterior and lateral); and CT of the chest, abdomen, and pelvis. If a primary bone tumor is suspected, the patient should be referred to an orthopaedic oncologist. If diagnostic testing reveals multifocal disease, biopsy of the primary malignancy or bone lesion should be performed to determine definitive diagnosis prior to treatment of the fracture. Evidence shows that not all metastatic disease should be treated with primary stabilization.

Surgical management should be based on the primary malignancy and life expectancy of the patient. In patients with advanced metastatic breast cancer, 65 percent to 75 percent will have bony metastases. Pathologic fractures associated with breast cancer can be managed safely with primary stabilization followed by adjuvant radiation. Because fracture healing rates are reportedly at only around 37 percent, solid fixation that allows for immediate use of the extremity is indicated. Breast cancer is predominately radiosensitive, so postoperative radiation is typically indicated.

Pathologic fracture associated with metastatic lung cancer also should be stabilized primarily and treated postoperatively with adjuvant radiation. Lung cancer has intermediate sensitivity to radiation.
Pathologic fracture through metastatic lung cancer should not be expected to heal, especially in combination with postoperative radiation. Therefore, robust surgical fixation allowing immediate full use of the extremity should be performed.

Bone metastases occur in up to a quarter of patients with renal cell carcinoma (RCC), and management of pathologic fractures in RCC requires special considerations (Fig. 1). RCC metastases are generally more vascular than other metastatic lesions, and preoperative embolization may be indicated to prevent excessive blood loss. The orthopaedic surgeon should be prepared for potentially significant blood loss with or without preoperative embolization and plan accordingly. In the setting of isolated or limited metastatic disease, patients with RCC may benefit from primary en bloc resection of the area with reconstruction due to reported extended survival, as well as the destructive and progressive nature of RCC metastases. Surgeons should take into account the extent of metastatic disease and prognosis when considering options involving extensive reconstruction that would require lengthy postoperative rehabilitation. Postoperative radiation is not indicated, as RCC generally is not radiosensitive (Fig. 2).

Fig. 1 Solitary metastatic lesion of primary renal cell carcinoma involving the proximal humerus
Images Courtesy of Shervin V. Oskouei, MD

Fig. 2 Wide resection and endoprosthetic reconstruction of the proximal humerus for solitary renal metastasis
Images Courtesy of Shervin V. Oskouei, MD

Management of pathologic fractures associated with metastatic thyroid cancer lesions also presents unique challenges. Thyroid cancer metastases, like RCC, can be highly vascular; therefore, preoperative embolization should be considered. Surgical management should take into account the extent of metastatic disease and type of thyroid cancer. In some instances, metastasectomy with reconstruction may extend survival and prevent the need for additional interventions for progressive disease. On average, life expectancy in patients with metastatic thyroid cancer is longer than that in many other primary cancers. As a result, survivability of the chosen construct must be considered. Regardless of type of surgical management, adjuvant radiation is beneficial, as thyroid cancer is moderately radiosensitive.

Optimal management of pathologic fracture in the setting of metastatic melanoma may involve metastasectomy rather than primary stabilization; however, projected survival time must be considered. Melanoma is moderately sensitive to radiation, so adjuvant therapy is indicated.

Numerous other considerations exist in the treatment of patients with metastatic disease. Orthopaedic surgeons who evaluate patients with known or suspected metastases must focus on fracture prevention and reduction of further morbidity. For most long bone lesions, intramedullary devices are preferable to plates and screws. Radiolucent intramedullary rods, such as those made of carbon fiber instead of the traditional titanium, may allow visualization of the tumor and disease progression. Some data support better radiation delivery with such devices (Fig. 3).

Fig. 3 Use of a radiolucent cephalomedullary femoral device to stabilize a metastatic lesion involving the subtrochanteric area of the femur
Images Courtesy of Shervin V. Oskouei, MD

Although this synopsis is not a comprehensive review of malignancies potentially associated with pathologic fractures, it demonstrates the complex decision-making for surgeons treating pathologic fractures secondary to metastatic disease. Consultation with or referral to an orthopaedic oncologist and a multidisciplinary approach often are indicated in the setting of pathologic fracture.

Shervin V. Oskouei, MD, is an assistant professor of orthopaedic surgery in the Department of Orthopaedic Surgery at the Emory University School of Medicine in Atlanta. He has an interest in limb salvage surgery for oncology and complex adult reconstruction.

Anna Greenwood, MD, a graduate of the orthopaedic residency at Virginia Commonwealth University Medical Center in 2018, is currently completing an orthopaedic oncology fellowship at Emory University.