Is cryotherapy harmful

Cochrane

Question

Is cryotherapy (cold therapy) useful or harmful for local destruction of liver metastases?

background

When cancer spreads around the body (metastasis), one of the most common organs affected is the liver. Liver cancer (primary liver cancer) and colon cancer metastases are the most common forms of cancer in the liver. More than half of people with liver metastases die from complications. Cryotherapy is a method used to destroy metastases in the liver. To do this, a special probe must be placed near the metastasis. Extreme cold is transmitted to the affected area via the probe. The cold is generated by liquid nitrogen or argon gas. The placement of the probe can be done with the help of ultrasound or computed tomography (a special X-ray method). The rapid freezing process kills the cancer cells and the metastasis shrinks. However, it is not clear whether this treatment will extend people's lives or improve their quality of life.

We have summarized the evidence on the effects of cryotherapy in destroying liver metastases. We looked for studies in patients with liver metastases from any cancer that compared cryotherapy with either no treatment for liver metastases or any other treatment option. We wanted to study the effect of cryotherapy on risk of death, quality of life, and adverse events (treatment-related side effects).

Study characteristics

We conducted our last search for evidence in June 2018. We only included one study conducted in Ukraine in this review. In 66% of the participants in this study, the primary tumor was in the intestine. In the remaining study participants, the primary tumor was located in the stomach, chest, skin or other parts of the body. The cancer had metastasized to the liver in all of the study participants. In the study, 123 participants were randomly assigned to either cryotherapy (63 patients) or conventional surgery (affected parts of the liver were removed; 60 patients).

Financial support

No information was available on the financing of the study.

Main results

The study was at high risk for bias. The participants were followed up for up to 10 years (minimum: five months). It was reported that the 10-year mortality rate was 81% (51/63) in the cryotherapy-treated group and 92% (55/60) in the conventional surgery group. We rate the trustworthiness of the evidence as low. We found no evidence of a difference in the proportion of participants with recurrent malignant tumors in the liver: 86% (54/63) of participants in the cryotherapy-treated group and 95% (57/60) of participants in the conventional surgery-treated group Group developed a new malignant tumor (low confidence level of evidence). The frequency of reported complications, with the exception of postoperative pain, was similar in both comparison groups (cryotherapy and conventional surgery). Both minor and severe pain were reported more frequently in the cryotherapy group, while severe pain was reported more frequently in the group treated with conventional surgery. However, it was not reported whether there was a difference. The incidence of adverse events (adverse events or complications) was broadly similar in both groups, but there appeared to be a difference in pain intensity and frequency between the groups. There were no intervention-related deaths or bile leaks. The study did not provide data on quality of life, mortality from cancer, or time to liver metastasis.

Reliability of Evidence

The reliability of the evidence for the effectiveness of cryotherapy compared to conventional surgery in people with liver metastases is low. We are uncertain about our estimate and cannot make any definite statement as to whether cryotherapy is useful or harmful compared to conventional surgery. We found no evidence of the benefit or harm of cryotherapy compared to no intervention or compared to systemic treatments.