A high-efficiency hepatic cryosurgical unit has been developed and evaluated. It is capable of simultaneously driving three implantable insulated cryoneedle probes. The system has been used to treat 18 patients with secondary and 4 patients with primary liver cancer: open (n = 12), total laparoscopic (n = 6), laparoscopic assisted (n = 4). In three patient laparoscopic cryotherapy was repeated inside 6 months. Intraoperative bleeding was encountered in three patients undergoing high-volume hepatic freezing but the bleeding was easily controlled. A fall in the core body temperature was encountered in 10 out of 22 patients and averaged 0.4 degree C. There was one postoperative death from liver failure in an 80-year-old patient in whom a large hepatoma was frozen. The most consistent postoperative biochemical change was hyperbilirubinaemia (n = 3). A right-sided pleural effusion developed in two patients after freezing of lesions on the superior surface of the right lobe. A survival benefit was encountered in three patients, one with central cholangiocarcinoma and the other two with large solitary secondary deposits (melanoma, colon cancer). Seven patients with multiple metastases and two patients with large hepatomas developed recurrence at the frozen site or elsewhere in the liver inside 12 months of follow-up and no clinical benefit could be demonstrated by cryotherapy in this group. In nine patients, the follow-up has been too short (< 18 months) to permit any conclusion on outcome. The current limitations of hepatic cryotherapy are largely due to incomplete tumor destruction.(ABSTRACT TRUNCATED AT 250 WORDS)