The strengths of this definition are its simplicity and its

The strengths of this definition are its simplicity and its usefulness in translating existing data into daily practice. The shortcomings of this definition include the lack of uniform criteria to suggest an impending fracture as well as the variable definitions of spinal cord cdc42 pathway or cauda equina compression. Although 9 studies excluded patients with spinal cord compression alone, and 3 studies excluded patients with spinal cord compression or cauda equina compression, none provided a definition or associated symptoms of such conditions. Furthermore, only 4 studies by Roos et al. [19], Hartsell et al. [20], Safwat et al. [23], and Foro Arnalot et al. [25] required clinical or radiological evidence of compression. Still, in spite of these nuances, the case can be made for conformity of treatment in patients whose clinical circumstances reside within the confines of this definition. In contrast, the use of SF and MF radiation therapy treatments vary in patients with complicated bone metastases. A randomized controlled trial by Patchell et al. evaluating the efficacy of direct decompressive surgery showed that decompressive surgical resection and post-operative MF radiation therapy (30Gy in 10 fractions) combined is superior to radiation therapy alone for patients with cord compression by metastatic cancer restricted to a single area and fair to good motor function below the injury level [30]. Furthermore, MF (median dose 30Gy) in postoperative radiation therapy following stabilization of impending pathological fracture was associated with increased functional status, decreased failure of the prosthesis, and perhaps improved overall survival [31]. In another randomized trial by Maranzano et al., 8Gy SF radiation therapy was shown to be effective in achieving palliation in patients with metastatic spinal cord compression by bone metastases and poor performance status. However, this may be attributed to the short life expectancy (6 months or less) of included patients, who would benefit from minimal toxicity and convenience of SF [32]. Moreover, a study by Roos et al. comparing SF and MF in patients with bone metastases presenting with neuropathic pain suggested SF was not as effective as MF in treating neuropathic pain, although it was not statistically significantly worse [19].
Conflicts of interest statement
Acknowledgment We thank the generous support of Bratty Family Fund, Michael and Karyn Goldstein Cancer Research Fund, Pulenzas Cancer Research Fund, Joseph and Silvana Melara Cancer Research Fund, and Ofelia Cancer Research Fund.
Introduction The rare disease now known as primary lymphoma of bone (PLB) was initially described by Oberlin [1]. Parker and Jackson later described PLB as a distinct entity [2], which is understood to be a malignant lymphoid infiltrate of bone [3]. While this may include cortical or soft tissue invasion, the diagnosis generally excludes lymph node or distant visceral involvement to be considered a primary lymphoma of bone [4]. This definition has been contended throughout the literature, with some authors permitting lymph node involvement [5–7], though most authors recognize the disease as lymphoma localized only to bone upon diagnosis. Primary lymphoma of bone affects 1.7/1,000,000 patients in the US [8]. Previous studies have suggested PLB comprise 5% of all extranodal lymphomas [9], and 3% of all bone malignancies [10]. Due to the low incidence of PLB, most prior studies have been from a single-institution, and have had small sample sizes [10–15]. The Surveillance, Epidemiology, and End Results (SEER) database is a publically available database created for the purpose of collecting demographic, clinical, and outcome data for cancer patients in the United States. There remains scant literature published using this database to evaluate larger patient populations [8]. The purpose of this population-based study was to identify prognostic factors for survival in patients with PLB, in order to determine whether disparities in survival exist between demographic cohorts. In doing so, the current study aimed to determine the prognostic significance of different tumor-specific and anatomic considerations that may influence overall survival from this disease. The authors chose to limit this study to adult patients, because PLB in children is often considered and treated as a systemic disease [16].