Page 102 - Predicting survival in patients with spinal bone metastasesL

CHAPTER VII
stereotactic radiotherapy 10-12. Therefore, the role of SINS in assessing this specific endpoint is debatable.
The aim of the current study was to determine the predictive value of the total and individual components of the SINS system for spinal instability in a cohort of patients with spinal bone metastases, treated with radiotherapy. Secondly, the interobserver agreement of both the total categorical SINS score and the individual components was determined.
PATIENTS AND METHODS
All consecutive patients who were treated with radiotherapy for symptomatic SBM between January 2000 and December 2010 in the Leiden University Medical Center, the Netherlands, and also had pretreatment computed tomography (CT) imaging were eligible for inclusion in this retrospective cohort study. In order to ensure accurate correlation between the clinical situation and the obtained images, the maximum accepted time between the diagnostic CT scan and start of treatment was two months. Patients who had already been stabilized were excluded, leaving the patients in whom there is clinical equipoise regarding the best treatment strategy and thus reflecting the more important clinical scenario in daily practice. Only a single metastatically affected vertebra was evaluated per patient. This selection was determined based on inclusion within the radiation field. If multiple vertebrae within the same radiation field were affected by metastatic disease, the vertebra with the highest score on the SINS components location or vertebral body collapse was selected for the analysis.
Each vertebral segment was scored according to the SINS criteria as described by Fisher et al5. The individual SINS components consisted of location (junctional, mobile, semi-rigid, and rigid spine), type of pain (mechanical, non-mechanical, pain-free), type of lesion (lytic, mixed, sclerotic), spinal alignment (subluxation/ translation, kyphosis/scoliosis, normal), presence of baseline VCF (>50% collapse, <50% collapse, no collapse but >50% of the body involved, or none of the above), and whether the tumor involved the posterolateral elements (bilateral, unilateral, none). The radiological SINS components bone lesion, alignment, vertebral body collapse, and posterolateral involvement of spinal elements were assessed
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