Embolization for RCC: shift in treatment paradigm?

Summary

Researchers from Karolinska University Hospital in Stockholm have recently published their results of a prospective controlled trial on renal cell carcinoma (RCC) embolization. RCC is typically managed through nephron-sparing surgery, radical nephrectomy, ablation, or active surveillance. In this manuscript, the authors compared doxorubicin eluting embolic (DEE) to bland TAE. A total of 12 patients with average tumor size of 3.2 cm +/- 0.62 were randomized to receive DEE or TAE before a planned surgery. Size of embolic was determined on basis of degree of vascularity and ranged from 75-150 micron, 100-300 micron, and 300-500 micron. A CT was performed prior to surgical removal to assess treatment response. DEE transarterial chemoembolization (n = 6) resulted in a significantly (P = .018) higher degree of necrosis with an average of 88.3% compared with TAE (n = 5), which resulted in an average of 29.4%, as evaluated by CT. Histopathologic evaluation showed similar results (P = .016) with an average necrosis of 87.5% for DEE transarterial chemoembolization (n = 4) versus 26% for TAE (n = 5). Percentage of necrosis seen on microscopy correlated significantly (P = .0005) with radiologic findings, as 4 tumors in each arm were evaluated by both CT and microscopy. No major complications were observed in either group. The authors concluded that TACE is safe to be performed for localized RCC and has a significantly superior effect when compared with TAE.

Images of RCC treated by transarterial chemoembolization in patient 12. (a) Subtraction angiography image obtained after selective catheterization of the left renal artery showed contrast-filled intratumoral vessels (arrowhead) before transarterial chemoembolization. (b)Subtraction angiography image obtained during transarterial chemoembolization showed no contrast-filled vessels in the center of the tumor owing to ongoing embolization. The area adjacent to RCC (arrowhead) shares its blood supply with the tumor. (c) CT imageobtained before transarterial chemoembolization showed contrast enhancement in RCC (arrowhead). (d) CT image obtained 4 weeks after transarterial chemoembolization showed no contrast enhancement in RCC (arrowhead). Infarcted renal tissue (arrow) is adjacent to the treated tumor.

Commentary

This manuscript is noteworthy as it opens the avenue for more catheter-based research for RCC locoregional treatment. The authors were able to demonstrate a statistically significant increased response to doxorubicin DEB compared to bland embolic. While both embolics contained residual tumor on pathologic evaluation, DEB had significantly better tumor response. This is interesting as systemic doxorubicin is not known to have a significant impact on RCC. Further, many tumors can become resistant to the effects of doxorubicin when they are ischemic (as with embolization). Clearly, there is more happening at the tumor level than we currently understand. However, is this all a moot point given the current treatment paradigm in RCC? There is a relatively low likelihood that a patient would not be a candidate for partial nephrectomy or ablation and have a tumor undergoing rapid enough growth to require palliative treatment. As such, this manuscript may be more impactful in what it says about the local effects of embolization and image-guided drug delivery and is unlikely to change RCC treatment algorithms.

Click here for abstract

Karalli A, Ghaffarpour R, Axelsson R, Lundell L, Bozoki B, Brismar T, Gustafsson O. Transarterial Chemoembolization of Renal Cell Carcinoma: A Prospective Controlled Trial. J Vasc Interv Radiol. 2018; 12:1664-1672

Post Author:
Luke R. Wilkins, MD
Assistant Professor
Department of Radiology and Medical Imaging
Section of Vascular and Interventional Radiology
University of Virginia
@LukeWilkins_UVA