Cochrane: Liver cancer (hepatocellular carcinoma) is the fifth most common cancer worldwide. In the majority of people, liver cancer is diagnosed at advanced stages of the disease and is mostly accompanied by liver cirrhosis. In high-income countries, about 30% of people present with the more favourable early liver cancer. For these people, percutaneous ablation techniques (destruction of the cancer cells by heat, cold, or chemical substances such as ethanol), surgical resection (removal of part of the liver), and liver transplantation (which is limited by organ donor shortage) are currently considered potentially curative treatments.
We aimed to investigate the role of percutaneous injection of ethanol (PEI) and acetic acid (PAI) as compared with other treatments or no intervention for early liver cancer. This review excluded the effects of radiofrequency thermal ablation as this has been already addressed in a previous Cochrane Hepato-Biliary Group systematic review.
Study characteristics
The review authors searched the medical literature in order to clarify the role of PEI and PAI for the treatment of liver cancer and to compare their benefits and harms with no treatment, with placebo (a pretend treatment), or with other treatments (such as laser, cryoablation, or microwave ablation; hepatic resection; and liver transplantation). We collected and analysed data from randomised clinical trials (where people were allocated at random to one of two or more treatments groups) of people with liver cancer who were able to receive PEI or PAI. Evidence is current to July 2014.
Key results and quality of evidence
The review authors only identified three randomised trials with 261 participants. The risk of bias was low in one and high in two trials. We found two trials that compared PEI versus PAI and one trial that compared PEI versus surgery. We found no trials that compared PEI or PAI versus sham (pretend) intervention, best supportive care, cryotherapy, laser-induced thermotherapy, or high-frequency ultrasound. We found no randomised trials that compared PAI versus surgery.
The review authors found low-quality evidence suggesting that PEI yielded the same result as PAI regarding overall survival (the length of time that the person remains alive) and recurrence-free survival (time that the person remains free of cancer). We calculated the number of participants that would be required to judge a relative risk reduction (relative risk is a comparison of the risk of an event happening for one treatment group compared with another treatment group) for survival of 20%. We found that for the comparisons PEI versus PAI, the number of participants was too low to reach valid conclusions. In both groups, participants reported the occurrence of mild side effects such as transient fever, flushing, and local pain. Based on one randomised trial with high risk of bias, there was very low quality evidence that surgical resection does not seem to be superior to PEI in people with early liver cancer. Of note, no severe side effects occurred in people treated with PEI while there were three postoperative deaths in people treated surgically. Again, too few participants were randomised to claim or reject important differences.
There is a need for more randomised clinical trials assessing interventions for people with early-stage liver cancer. Such trials should be conducted with low risks of bias (systematic errors, that is overestimation of benefits and underestimation of harms) and of play of chance (random errors, that is errors due to too few participants and too few outcomes).
- See more at: http://summaries.cochrane.org/CD006745/LIVER_percutaneous-ethanol-injection-for-the-treatment-of-early-liver-cancer#sthash.7kfz4UGR.dpuf