Correlation Between the Spinal Instability Neoplastic Score (SINS) and Patient Reported Outcomes

STUDY DESIGN: International multicenter prospective observational cohort study on patients undergoing radiation +/− surgical intervention for the treatment of symptomatic spinal metastases. OBJECTIVES: To investigate the association between the total Spinal Instability Neoplastic Score (SINS), individual SINS components and PROs. METHODS: Data regarding patient demographics, diagnostics, treatment, and PROs (SF-36, SOSGOQ, EQ-5D) was collected at baseline, 6 weeks, and 12 weeks post-treatment. The SINS was assessed using routine diagnostic imaging. The association between SINS, PRO at baseline and change in PROs was examined with the Spearmans rank test. RESULTS: A total of 307 patients, including 174 patients who underwent surgery+/− radiotherapy and 133 patients who underwent radiotherapy were eligible for analyses. In the surgery+/− radiotherapy group, 18 (10.3%) patients with SINS score between 0-6, 118 (67.8%) with a SINS between 7-12 and 38 (21.8%) with a SINS between 13-18, as compared to 55 (41.4%) SINS 0-6, 71(53.4%) SINS 7-12 and 7 (5.2%) SINS 13-18 in the radiotherapy alone group. At baseline, the total SINS and the presence of mechanical pain was significantly associated with the SOSGOQ pain domain (r = −0.519, P < 0.001) and the NRS pain score (r = 0.445, P < 0.001) for all patients. The presence of mechanical pain demonstrated to be moderately associated with a positive change in PROs at 12 weeks post-treatment. CONCLUSION: Spinal instability, as defined by the SINS, was significantly correlated with PROs at baseline and change in PROs post-treatment. Mechanical pain, as a single SINS component, showed the highest correlations with PROs.