AIM:To determine the safety and efficacy of efficacy of percutaneous cryosurgery for treatment of patients with hepatic colorectal metastases. METHODS: Three hundred and twenty-six patients with non-resectable hepatic colorectal metastases underwent percutaneous cryosurgery under the guidance of ultrasound or CT. Follow-up was 1 mo after cryosurgery and then every 4 mo thereafter by assessment of tumor markers, liver ultrasonography, and abdominal CT. For lesions suspicious of recurrence, a liver biopsy was performed and subsequent repeat cryosurgery was given if histology was positive for cancer. RESULTS: All patients underwent a total of 526 procedures of cryosurgery. There were 151 patients who underwent repeat procedures of cryosurgery for recurrent tumors in the liver and extrahepatic places. At 3 mo after cryosurgery, carcinoembryonic antigen (CEA) levels in 197 (77.5%) patients who had elevated markers before cryosurgery decreased to normal range. Among 280 patients who received CT following-up, cryotreated lesions showed complete response (CR) in 41 patients (14.6%), partial response (PR) in 115 patients (41.1%), stable disease (SD) in 68 patients (24.3%) and progressive disease (PD) in 56 patients (20%). The recurrence rate was 47.2% during a median follow-up of 32 mo (range, 7-61). Sixty one percent of the recurrences were seen in liver only and 13.9% in liver and extrahepatic areas. The recurrence rate at cryotreated site was only 6.4% for all cases. During a median follow-up of 36 mo (7-62 mo), the median survival of all patient was 29 mo (range 3-62 mo). Overall survival was 78%, 62%, 41%, 34% and 23% at 1, 2, 3, 4 and 5 years, respectively, after the treatment. Patients with tumor size less than 3 cm, tumor in right lobe of liver, lower CEA levels (< 100 ng/dL) and post- cryosurgery TACE had higher survival rate. There wasno significant difference in terms of survival based on the number of tumors, pre-cryosurgery chemotherapy and the timing of the development of metastases (synchronous vs metachronous). Patients who underwent 2-3 procedures of cryosurgery had increased survival compared to patients who received cryosurgery once only. There was no intra-cryosurgery mortality. Main adverse effects, such as hepatic bleeding, cryoshock, biliary fistula, liver failure, renal insufficiency and liver abscess were only observed in 0.3%-1.5% of patients. CONCLUSION:Percutaneous cryosurgery was a safe modality for hepatic colorectal metastases. Rather than an alternative to resection, this technique should be regarded as a complement to hepatectomy and as an additional means of achieving tumor eradication when total excision is not possible. AIM: To determine the safety and efficacy of efficacy of percutaneous cryosurgery for treatment of patients with hepatic colorectal metastases. METHODS: Three hundred and twenty-six patients with non-resectable hepatic colorectal metastases underwent percutaneous cryosurgery under the guidance of ultrasound or CT. Follow -up was 1 mo after cryosurgery and then every 4 mo thereafter by assessment of tumor markers, liver ultrasonography, and abdominal CT. For lesions suspicious of recurrence, a liver biopsy was performed and subsequent repeat cryosurgery was given if histology was positive for cancer. RESULTS: All patients underwent a total of 526 procedures of cryosurgery. There were 151 patients who underwent repeat procedures of cryosurgery for recurrent tumors in the liver and extrahepatic places. At 3 mo after cryosurgery, carcinoembryonic antigen (CEA) levels in 197 (77.5% ) patients who had elevated markers before cryosurgery decreased to normal range. Among 280 patients who received CT following-up, cryotreated lesions showed complete response (CR) in 41 patients (14.6%), partial response (PR) in 115 patients (41.1%), stable disease PD) in 56 patients (20%). The recurrence rate was 47.2% during a median follow-up of 32 mo (range, 7-61). Sixty one percent of the recurrences were seen in liver only and 13.9% in liver and During a median follow-up of 36 mo (7-62 mo), the median survival of all patients was 29 mo (range 3-62 mo). Overall survival was 78%, 62%, 41%, 34% and 23% at 1, 2, 3, 4 and 5 years, respectively, after the treatment. Patients with tumor size less than 3 cm, tumor in right lobe of liver , lower CEA levels (<100 ng / dL) and post-cryosurgery TACE had higher survival rate. There was no significant difference in terms of survival based on the number of tumors, pre-cryosurgery chemotherapy and the timing of the devPatients who underwent 2-3 procedures of cryosurgery had increased survival compared to patients who received cryosurgery once only. There was no intra-cryosurgery mortality. Main adverse effects, such as hepatic bleeding, cryoshock, biliary fistula, liver failure, renal insufficiency and liver abscess were only observed in 0.3% -1.5% of patients. CONCLUSION: Percutaneous cryosurgery was a safe modality for hepatic colorectal metastases. Rather than an alternative to resection, this technique should be regarded as a complement to hepatectomy and as an additional means of achieving tumor eradication when total excision is not possible.