Scheduling surgery after transarterial embolization: does timing make any difference to intraoperative blood loss for renal cell carcinoma bone metastases?

PURPOSE Our purpose is to clarify the optimal timing of surgery after transarterial embolization (TAE) for renal cell carcinoma (RCC) bone metastases. METHODS This retrospective study included 41 patients with RCC bone metastases embolized between 2013 and 2019. Different-sized particulate and/or liquid embolic agents were used for TAE. Embolizations were categorized into groups 1-3 according to the interval between TAE and surgery (group 1: <1 day, group 2: 1-3 days, group 3: >3 days). Degree of embolization after TAE was graded visually based on angiographic images (<50%, 50%-75%, 75%-90%, >90%). The relationship between the TAE-surgery interval and intraoperative blood loss (IBL) and the correlation between IBL and embolization grade were examined. Lesion sizes and the relationships among lesion localizations and contrast media usage, intervention time, and IBL were also analyzed. RESULTS Forty-six pre-operative TAEs (single lesion at each session) were performed in this study (26 in group 1, 13 in group 2, 7 in group 3). Lesion sizes and distributions were similar between groups (p = 0.897); >75% devascularization was achieved in 40 (TAEs 86.96%), but the IBL showed no correlation with the embolization rate (r=0.032, p = 0.831). The TAE-surgery interval was 1-7 days. The median IBL in group 1 (750 mL; range, 150-3000 mL) was significantly lower than those in the other groups (p = 0.002). Contrast media usage ( p = 0.482) and intervention times (p = 0.261) were similar for metastases at different localizations. IBL values after TAE were lower for extremity metastases (p = 0.003). CONCLUSION Bone metastases of RCC are well-vascularized, and to achieve lowest IBL values, surgery should preferably be performed <1 day after TAE.