OBJECTIVE To establish the prognostic importance of different patient and tumor characteristics in cryotherapy for liver metastases from colorectal cancer. BACKGROUND Hepatic cryotherapy has been used as a treatment of nonresectable liver metastases from colorectal cancer in almost 1000 patients worldwide, and its safety and efficacy are well established. However, tumor eventually recurs in most patients and they die of their disease. The knowledge of prognostic factors would allow the selection of patients who are more likely to benefit from this treatment and patients who may need additional treatment. METHODS Between April 1990 and May 1997, 195 patients were treated with hepatic cryotherapy. Out of this group, the authors identified 116 patients with colorectal cancer who received cryotherapy for ablation of liver metastases. Survival was estimated with the Kaplan-Meier method, using the log-rank test for univariate analysis for significance of possible prognostic factors. For multivariate analysis, a Cox regression was used. RESULTS One patient (0.9%) died of postoperative myocardial infarction. The total perioperative morbidity rate was 27.6%. Median survival and the 5-year survival rate were 26 months and 13.4%. The following factors were identified as independently associated with a favorable outcome: low presurgical serum level of carcinoembryonic antigen (CEA), small (< or =3 cm) diameter of cryoablated metastases, absence of untreated extrahepatic disease at laparotomy, absence of nodal involvement at primary resection, complete cryotreatment, synchronous development of liver metastases, and good or moderate differentiation of the primary tumor. Although univariate analysis suggested a favorable prognosis in patients who did not receive blood transfusion during surgery and patients younger than 51 years, this was not confirmed in multivariate analysis. In addition, normalization of the serum CEA level after treatment was an important prognostic marker in the subgroup of patients with elevated serum CEA levels before surgery. CONCLUSIONS Hepatic cryotherapy is a safe and effective treatment option for patients with nonresectable liver metastases from colorectal cancer, with promising results regarding survival. The prognostic factors established in this series may allow better patient selection to improve the outcome in suitable patients.