How useful is radiofrequency ablation (RFA) in treating liver metastases from colorectal cancer?
To answer that question, American Society for Clinical Oncology scientists included two C3 advocates, Rob Michelson and Dr. Andrew Guisti, on an expert panel looking at published RFA research.
The Expert Panel wishes to dedicate this Clinical Evidence Review to Rob Michelson, who served as the patient representative at the Panel meeting in October 2007 and passed away early in 2008. His contributions at the meeting and as a reviewer of the first draft were substantive and thought provoking.
While the panel could not find sufficient evidence to establish an evidence-based practice guideline for RFA to treat cancer that had spread to the liver from the colon or rectum, they did complete a review of existing studies and called for more research into the usefulness of RFA to improve outcomes for patients with liver metastases from colorectal cancer.
In reviewing existing medical literature, the panel focused on three important questions:
- The effectiveness of RFA versus surgical resection for those tumors that could be surgically removed (resectable).
- The usefulness of RFA to treat tumors that could not be surgically removed (unresectable).
- RFA approaches (open, laparoscopic, or percutaneous).
Radiofrequency ablation uses metal probes and low frequency electric current to heat and destroy tumor tissue. Radiofrequency also seals small blood vessels to reduce bleeding risk. Because heat is confined to the cancerous tissue, patients don’t feel it and normal liver tissue is protected.
RFA can be performed during an open surgery, laparoscopically, or through the skin percutaneously. During all treatments, good imaging is critical to be able to see the tumor being ablated. CT scans, MRI, or ultrasound can be used during percutaneous RFA, but intraoperative ultrasound is used during an open or laparoscopic operation.
Postablation syndrome occurs in about 30 to 40 percent of patients, usually beginning three days after an RFA procedure and lasting about five days. Patients experience low-grade fever, chills, malaise, achiness, pain, and nausea and vomiting. It is more common when large tumor volumes are treated and is probably due to inflammation as treated tissues die.
Other complications from RFA were relatively low and were more common in open as opposed to percutaneous methods. There were fewer complications among more experienced doctors and in hospitals with more RFA experience.
The Expert Panel included an Appendix to help doctors discuss options with patients to manage liver metastases from colorectal cancer.
Panel members concluded,
There is a compelling need for more research to determine the efficacy and utility of RFA to increase local recurrence-free, progression-free, and disease-free survival as well as overall survival for patients with colorectal hepatic metastases. Clinical trials have established that hepatic resection can improve overall survival for patients with resectable colorectal hepatic metastases.