A therapy for smaller cancers of the liver known as radiofrequency ablation may be more effective than the more conventional treatment known as percutaneous ethanol injection, say doctors who compared the two treatment approaches in a new study.¹

Two Distinct Therapies
Radiofrequency ablation is an emerging form of liver cancer treatment meant for patients who have tumors that cannot be removed surgically for various reasons.² Radiofrequency ablation, or RFA, involves the use of energy that is delivered through a metal probe inserted into tumors or other tissues. When the probe is in place, metal prongs open out to extend the reach of the therapy. RF energy is then directed into the tumor, causing atoms in the cells to vibrate and create friction, which in turn, creates high heat and kills the targeted cells. Doctors typically use imaging software like computed tomography (CT scan) or MRI (magnetic resonance imaging) to ensure that the therapy has been effective.³

Percutaneous ethanol injection is considered the more standard non-surgical treatment approach for liver cancer. It's been an available treatment for more than 20 years. Using a thin needle and ultrasound imaging or CT scan as a guide, doctors inject alcohol directly into the tumor tissue.

When it comes to smaller liver cancer tumors (those less than 4 centimeters (about 1.5 inches) in size), medical experts at Chang Gung University in Taipei, Taiwan say RFA is better than percutaneous ethanol injection.

Docs: RFA is Better for Smaller Cancers
To compare success rates using radiofrequency ablation versus ethanol injection, Shi-Ming Lin, MD, in the Liver Research Unit at the university and his colleagues recruited 157 men and women who had been diagnosed with smaller hepatocellular carcinomas for the study.

Lin's team divided the patients into three groups. One group of patients was given a standard percutaneous ethanol injection dose, a second group received a higher dose of ethanol, and the final group underwent RFA. They measured the rate of cell necrosis, or death; overall patient survival; whether any existing tumors developed further; the incidence of additional new tumors; and the odds of cancer-free patient survival.

After all patients had undergone their assigned treatment, Lin and his team followed each of them for an average of 2 years postoperatively. They noted that outcomes incrementally improved with standard percutaneous ethanol injection, as well as higher dose ethanol injection. But outcomes were the most successful for patients who underwent radiofrequency ablation.

In the group given standard ethanol injection, complete tumor necrosis was 88%. But the rate of necrosis was 92% in the group given a higher dose of ethanol injection, and 96% in the group that underwent RFA.

"Significantly fewer sessions were required to achieve complete tumor necrosis in the radiofrequency ablation group than in the other 2 groups," the researchers wrote.

Tumor progression rates were the lowest in the group that received RFA compared to ethanol injection, and both the cancer-free and overall rates of survival of the patients, collectively, were highest in those that underwent radiofrequency ablation compared to the other treatments.

All outcomes in the study were found to be significant.

Study Caveat
The only drawback to this study, Lin and his team wrote, was that they used a lower power generator and smaller electrode in the RFA procedures than what are being developed and used by other clinicians today.

But if they had used more standard equipment, they wrote, the results would likely have been even better. "Various recent advances in radiofrequency electrodes with a larger ablation zone and other types of radiofrequency generators with a higher radiofrequency power … may cause the rate of complete tumor necrosis or local tumor progression to change when these new devices are used to perform radiofrequency ablation in hepatocellular carcinoma."

1. Lin SM, Lin CJ, Lin CC, Hsu CW, Chen YC. Radiofrequency ablation improves prognosis compared wieht ethanol injection for hepatocellular carcinoma < or =4 cm. Gastroenterology 2004 Dec;127(6):1714-23.
2. Ng KK, Lam CM, Poon RT, Ai V, Tso WK, Fan ST. Thermal ablative therapy for malignant liver tumors: a critical appraisal. J Gastroenterol Hepatol 2003 Jun;18(6):616-29.
3. Society of Interventional Radiology. About RFA Procedures.

John Martin is a long-time health journalist and an editor for Priority Healthcare. His credits include coverage of health news for the website of Fox Television's The Health Network, and articles for the New York Post and other consumer and trade publications.