AB074. Propensity-score Matched Analysis to Evaluate the Safety and Utility of Intraoperative Cell- Salvaged Autologous Blood Transfusion in Metastatic Spine Tumour Surgery

BACKGROUND:Blood loss is an important consideration in metastatic spine tumour surgery (MSTS). Allogeneic blood transfusion (ABT) is the current standard of blood replenishment for MSTS despite known complications. Salvaged blood transfusion (SBT) through intraoperative cell salvage addresses the majority of complications related to ABT. However, the use of SBT in MSTS still remains controversial. We aim to conduct a prospective propensity-score (PS) matched analysis to evaluate the long-term clinical outcomes of intraoperative cell salvage (IOCS) in MSTS. METHODS:Our study included 98 patients who underwent MSTS from 2014-2017. A PS matched cohort was created using the relevant and available predictors of treatment assignment and outcomes of interest. Clinical outcomes consisting of overall survival (OS), as well tumour progression (TP) that was evaluated using RECIST (v1.1) were compared in the matched cohort. RESULTS:Our study had a total of 98 patients with a mean age of 60 years old. A total of 33 patients received SBT. Overall median blood loss was 600 mL [interquartile range (IQR): 300-1,000 mL] and overall median blood transfusion (BT) was 620 mL (IQR: 110-1,600 mL). Group PS matching included 30 patients who received ABT and 28 patients who received SBT. There was also no significant difference between the OS of patients who underwent ABT or SBT (P=0.19). SBT did not show any significant increase in 4-year tumour progression [PS matched hazard ratio (HR) 3.659; 95% confidence interval (CI): 0.346-38.7; P=0.28]. CONCLUSIONS:SBT has been shown to have similar clinical outcomes to that of ABT in patients undergoing MSTS, with potential benefits of avoiding complications and costs of ABT. This will be the first long-term PS matched analysis to report on the clinical outcomes of SBT and affirms the clinical role of SBT in MSTS today.