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ASCO calls for more research into radiofrequency ablation of hepatic metastases from CRC
Currently there is not enough evidence to form a practice guideline.
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After a comprehensive systematic review of literature published from 1996 to 2007, an American Society of Clinical Oncology panel concluded that there is not enough clinical evidence to construct a guideline for the use of radiofrequency ablation for patients with extrahepatic colorectal cancer.
A clinical evidence review was published online Oct. 19 in the Journal of Clinical Oncology.
The panel reviewed 245 articles collected in Medline and the Cochrane Library to develop the evidence review of the use of radiofrequency ablation in colorectal cancer. The panel considered the efficacy of surgical hepatic resection vs. radiofrequency ablation for resectable tumors, the utility of radiofrequency ablation for unresectable tumors and which radiofrequency ablation technique — open, laparoscopic or percutaneous — was optimal.
Its recommendations were based on evidence from single-arm, retrospective and prospective trials. No randomized controlled trials were included in the review because radiofrequency ablation has not undergone such a trial. The panel concluded that “there are no compelling data to guide use of radiofrequency ablation in patients with viable extrahepatic disease” and “radiofrequency ablation in the setting of known extrahepatic disease is not supported by data at this time.”
Al B. Benson III, MD, associate director for clinical investigation at the Robert H. Lurie Comprehensive Cancer Center of Northwestern University and a member of the panel that drafted the guidelines, said there is a lack of level-one evidence.
“There is extensive literature, but the literature is what we consider observational,” Benson told HemOnc Today. “When you have regimens that can improve survival for metastatic disease and you have surgical resection for metastatic disease that is curative in some cases, there is a need to define where other local interventions such as radiofrequency ablation fit into the mix. The only way we’re going to find out is not by doing simple observational studies but by conducting comparative trials.”
ASCO did not go so far as to discourage use of radiofrequency ablation until the device is more rigorously tested, and Benson said it would be difficult to phase out a treatment that has been in use for years.
The panel noted that patient reluctance to join trials, reluctance on the part of physicians to recommend enrollment to their patients and limited resources are obstacles to conducting more clinical trials. Benson said only 3% to 5% of patients with cancer participate in clinical trials, but designing a randomized, controlled trial to test the efficacy and utility of radiofrequency ablation would not be difficult. The panel suggested eight such trials, including a comparison between hepatic resection vs. radiofrequency ablation for resectable colorectal metastases or comparing systemic chemotherapy vs. radiofrequency ablation for liver-predominant colorectal cancer.
“This reflects, in part, questions that have been raised because of the current utilization of this technology,” Benson said. “Clinically, radiofrequency ablation is being used, but we don’t have a definitive answer about how much it improves outcomes for patients compared with chemotherapy in this specific case. Without these types of trials, we cannot adequately define the appropriate role for RFA in this population.”
Benson said medical devices are not tested as rigorously as other therapies for a variety of reasons, including commercial concerns. The panel urged manufactures of medical devices to take note of this review and allow prospective, randomized trials to define optimal use.
He wants the FDA to demand stronger testing of equipment such as radiofrequency ablation.
“We should see a shift when you have a device that is actually a therapy from which we would expect a certain level of efficacy. If you’re expecting a certain level of efficacy, then you should do comparative trials.” – by Jason Harris
Wong SL. J Clin Oncol. 2009;doi:10.1200/JCO.2009.23.4450.
