Bone metastatic disease and skeletal-related events are major complications for patients who are affected by oncological diseases. Spreading of the tumor to bone causes pain, hypercalcemia, functional impairment and affects survival. However, pathological fractures also represent a critical moment with a clearly negative impact on a patient’s quality of life.
One key outcome for management of patients with metastatic bone disease is the prevention of skeletal-related events because pathological fracture is correlated with increased mortality. It is estimated that 40% of patients with pathological fractures survive at least 6 months after their fracture and 30% of these patients survive more than 1 year. In this setting, the choice of who should be treated is strictly related to the predicted risk of fracture.
Mirels’ scoring system is a weighted scoring system to assess the risk of pathological fracture in long weight-bearing bones. It combines four radiological and clinical risk factors. A score of 4 to 6 indicates a lesion has a low risk of fracture and can be irradiated safely. However, a score of 8 or more means prophylactic internal fixation is required prior to irradiation. This score remains accurate and cost-effective, even though use of the CT-based structural rigidity analysis has been found, in some studies, to be more accurate.
Surgical approach principles
The surgical approach for bone metastases should always be part of a multidisciplinary approach that considers the following four key principles: 1) Patient selection based on prognosis and predicted survival is critical. Patients with an expected survival of more than 6 weeks warrant consideration of fracture stabilization. Patients with an expected survival of more than 6 months should be considered for endoprosthetic reconstruction; 2) The implant must be stable enough to allow immediate full weight-bearing, with a durability longer than the patient’s expected survival; 3) All areas of the bone affected by tumor should be addressed in any planned reconstruction; and 4) Postoperative radiotherapy is helpful in local control and should be applied to the entire bone.
Prosthetic replacement appears to be better than internal fixation as it allows for immediate weight-bearing, quick rehabilitation and superior long-term results. It should be considered the treatment of choice at specific sites, such as the proximal femur, as long as there is good local tumor control and stability of the implant. The recent introduction of dual-mobility prosthetic hip joints, which have dual-articulation of the acetabular component, in tumor-related hip replacement has substantially reduced dislocation rates, and the use of these is rapidly increasing. Moreover, we strongly suggest the use of cemented stems in prosthetic reconstruction in patients with bone metastases to reduce local relapse, as is widely reported in literature.
Thanks to the advances in chemotherapy, today the survival of patients with metastases continues to increase progressively. The orthopaedic surgeon and oncologist should consider this as part of a modern approach to patients with metastatic disease. Moreover, there is considerable attention given to, and an increasing number of reports in the literature about, the new concept of oligometastatic state. The term indicates a solid malignancy with metastatic localizations of a limited number (up to three or five based on histotype) in the same apparatus, where an aggressive treatment can be carried out with “curative” intent. Recent studies have shown that oligometastatic state is a significant favorable factor to improve survival and quality of life in tumors, such as those of lung and prostate cancer, if these are treated with chemotherapy and aggressive local therapy. Most of the recent studies have shown a better prognosis for patients with oligometastatic cancer treated with a high dose of radiation therapy.
Recent studies reported a long survival of patients with oligometastatic bone disease after they underwent resection with wide margins as local treatment. Indeed, it is hypothesized that an intralesional violation of the metastasis can increase its biological activity because of the growth factors associated with bleeding and hematoma. This is particularly true in solitary lesions, favorable histologies (renal, breast and prostate tumors), and a long, free interval in the time following treatment of primary tumor and responsiveness to systemic therapy.
In conclusion, resection and prosthetic reconstruction should be considered in impending/pathological fractures as it allows better local control and implant stability. Patients with oligometastases have to be treated as patients with a solitary lesion because aggressive surgery can improve the prognosis for these patients.
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- Steensma M, et al. Clin Orthop Relat Res. 2012;doi:10.1007/s11999-011-2047-z.
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- Andrea Angelini, MD, PhD, is an abstract reviewer for EFORT. Pietro Ruggieri, MD, PhD, is a board and ethics committee member of EFORT. Angelini and Ruggieri can be reached at department of orthopedics and orthopedic oncology, University of Padova, via 8 Febbraio, 2, Padova 35122, Italy. Angelini’s email: firstname.lastname@example.org. Ruggieri’s email: email@example.com.
Disclosures: Ruggieri reports he is a consultant for Exactech and Stryker. Angelini reports no relevant financial disclosures.