Long-term results of preventive embolization of renal angiomyolipomas: evaluation of predictive factors of volume decrease

To evaluate the efficacy of selective arterial embolization (SAE) of angiomyolipomas based on the percentage volume reduction after embolization and to identify predictive factors of volume decrease. Patients receiving prophylactic SAE of renal angiomyolipomas were included retrospectively over 3 years. The volume change after SAE and haemorrhagic or surgical events were recorded. Initial tumour volume, percentage tumour fat content, mean tumour density, embolic agent used, number of angiomyolipomas and tuberous sclerosis disease were evaluated as predictive factors of volume decrease. A total of 19 patients with 39 angiomyolipomas were included with median follow-up of 28 months (interquartile range 21-37 months). All treatments were technically successful (92 % primary and 8 % secondary). No distal bleeding or any increase in size or surgical nephrectomy after SAE was recorded. Mean volume reduction was 72 % (±24 %). Volumes before SAE (R2 = 0.276; p = 0.001), percentage fat content (R2 = 0.612; p < 0.0001) and mean angiomyolipoma density (R2 = 0.536; p < 0.0001) were identified as predictive factors of volume decrease. In multivariate regression, only percentage fat content influenced volume decreases. SAE is an efficient treatment for angiomyolipoma devascularisation and volume reduction. A significant reduction of volume is modulated by the initial volume and tissue composition of the tumour. (orig.)