Embolotherapy for Renal Tumors

Abstract

Embolotherapy of renal neoplasms is practiced for various hypervascular tumors including angiomyolipoma, renal cell carcinoma, and metastatic renal cancer. First conceived during 1970s, it was primarily advocated for palliative therapy of symptomatic renal cell carcinomas [1]. Currently, the indications for embolotherapy of malignant renal tumors include, in addition to palliation, preoperative treatment of large renal tumors to reduce intraoperative blood loss, and as an adjunct to radiofrequency ablation to reduce perfusion mediated cooling for a more effective ablation [2, 3]. Embolization of large hypervascular tumors prior to nephrectomy has been shown to significantly reduce the volume of blood transfused during surgery compared to those patients with tumors not embolized or incompletely embolized [2, 4]. In addition, preoperative embolization facilitates surgical dissection. Edema induced by embolization creates a definable plane within the renal parenchyma, and this reduces operative time [4, 5]. In patients with renal cell cancer extending to the renal vein, preoperative embolization may reduce the size of the tumor thrombus making it easier to resect [6, 7]. Though it has not been clinically proven, it is believed that embolization may induce sufficient inflammation, which may accentuate immune response to the tumor [8]. As a palliative measure, embolization helps in the management of pain, hematuria, and paraneoplastic syndromes such as hypercalcemia [9]. In patients with angiomyolipoma, embolotherapy is indicated for treatment of acute bleeding [10]. It helps to avoid nephrectomy and preserves renal function [10]. In addition, prophylactic embolization is often advocated in large angiomyolipomas (size >4 cm) to prevent bleeding and renal dysfunction [11].