AJR: IRs not on the same page about chemoembolization

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There is significant variability in chemoembolization use and technique among interventional radiologists (IRs) suggesting the need for continued clinical investigations to further optimize and standardize transcatheter therapies for liver tumors, according to a study published in the March issue of the American Journal of Roentgenology.

For the past 25 years, chemoembolization has been a widely used therapy for liver malignancies, according to study author Ron C. Gaba, MD, of the University of Illinois Medical Center at Chicago.

“Although similar principles of chemoembolization therapy are generally followed by IRs, there remains significant potential for disparity in use and application, technical methods, treatment approaches, and follow-up algorithms by virtue of variability in IR training; variation in local institutional philosophies, biases, and practice patterns; and lack of definitive therapeutic, follow-up, and retreatment protocols with level 1 evidence support,” wrote Gaba.

To assess these variations in practice patterns, Gaba invited 1,157 Society of Interventional Radiology (SIR) members with chemoembolization expertise to participate in an online questionnaire in August and September 2010. Of those invited, 268 responded to the 34-item survey for a 23 percent response rate.

Results showed that 61 percent of respondents performed one to five chemoembolizations per month and preferred drug-eluting beads to iodized oil for unifocal and multifocal hepatocellular carcinoma (HCC). For unifocal HCC, drug-eluting beads were preferred by 46 percent of respondents compared with 39 percent who preferred iodized oil, with reduced toxicity listed as the primary rationale for use. With regard to multifocal HCC, drug-eluting beads were preferred by 40 percent of respondents, compared with 30 percent who preferred iodized oil. However, 90Y radioembolization was preferred when portal vein thrombosis was present.

Interventional radiologists showed variability in absolute contraindications to chemoembolization, with the top two contraindications being biliary obstruction and main portal vein thrombosis.

“Discrepancies in chemoembolization practice are invariably related to the paucity of level 1 evidence support in the form of comparative studies assessing protocol-based outcomes,” wrote Gaba, who added that these differences likely translate into IR training variability, which, in turn, promotes further discrepancies in chemoembolization performance.

Gaba noted that there is no definitive consensus in medical literature regarding the preferable degree of tumor embolization during chemoembolization. SIR guidelines suggest further treatment for patients with HCC or liver metastases when new or residual disease is found at follow-up, but the American Association for the Study of Liver Diseases states that there are no prospective data to support retreatment. Gaba suggested additional exploration into the best follow-up methods and the optimal application of drug-eluting beads vs. oil-based drug delivery.

“Although variation may allow a certain degree of individualization of therapy and practice of the ‘art of medicine,’ consistent and homogeneous procedure application has significant benefits, including facilitation of comparative analysis between studies and flexibility in comparison of different technologies.”