Reliability of the Spinal Instability Neoplastic Score (SINS) among radiation oncologists: An assessment of instability secondary to spinal metastases

Charles G. Fisher, Rowan Schouten, Anne L. Versteeg, Stefano Boriani, Peter P. Varga, Laurence D. Rhines, Norio Kawahara, Daryl Fourney, Lorna Weir, Jeremy J. Reynolds, Arjun Sahgal, Michael G. Fehlings, Ziya L. Gokaslan

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Background: The Spinal Instability Neoplastic Score (SINS) categorizes tumor related spinal instability. It has the potential to streamline the referral of patients with established or potential spinal instability to a spine surgeon. This study aims to define the inter- and intra-observer reliability and validity of SINS among radiation oncologists.Methods: Thirty-three radiation oncologists, across ten international sites, rated 30 neoplastic spinal disease cases. For each case, the total SINS (0-18 points), three clinical categories (stable: 0-6 points, potentially unstable: 7-12 points, and unstable: 13-18 points), and a binary scale ('stable': 0-6 points and 'current or possible instability'; surgical consultation recommended: 7-18 points) were recorded. Evaluation was repeated 6-8 weeks later. Inter-observer agreement and intra-observer reproducibility were calculated by means of the kappa statistic and translated into levels of agreement (slight, fair, moderate, substantial, and excellent). Validity was determined by comparing the ratings against a spinal surgeon's consensus standard.Results: Radiation oncologists demonstrated substantial (κ = 0.76) inter-observer and excellent (κ = 0.80) intra-observer reliability when using the SINS binary scale ('stable' versus 'current or possible instability'). Validity of the binary scale was also excellent (κ = 0.85) compared with the gold standard. None of the unstable cases was rated as stable by the radiation oncologists ensuring all were appropriately recommended for surgical consultation.Conclusions: Among radiation oncologists SINS is a highly reliable, reproducible, and valid assessment tool to address a key question in tumor related spinal disease: Is the spine 'stable' or is there 'current or possible instability' that warrants surgical assessment?

Original languageEnglish
Article number69
JournalRadiation Oncology
Issue number1
Publication statusPublished - Mar 4 2014


  • Instability
  • Neoplasm metastasis
  • Radiation oncology
  • Reliability and validity
  • Spine

ASJC Scopus subject areas

  • Oncology
  • Radiology Nuclear Medicine and imaging


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