Phase I study of percutaneous cryotherapy for colorectal liver metastasis.

Background: The aim was to determine the safety and feasibility of percutaneous cryotherapy for treating irresectable colorectal liver metastases. Methods: Liquid nitrogen cryoprobes were inserted percutaneously into metastases using the Seldinger technique under computed tomographic guidance. Single-probe treatments were performed with either 3·6- or 6·3-mm cryoprobes (ice-ball volumes 18 and 59 cm3 respectively), or dual-probe treatments with two adjacent 6·3-mm probes (ice-ball volume 205 cm3). Treatment involved a single freeze–thaw cycle. Results: Fifteen patients received 25 single-probe treatments and seven patients received 14 dual-probe treatments. The treatment-related mortality rate was zero and complications occurred after six of 39 treatments. Liver metastasis growth was significantly delayed for 2 months after dual-probe but not single-probe treatment. Metastasis cryotherapy stimulated an immediate rise, followed by a fall, in serum carcinoembryonic antigen (CEA) level, associated with immune upregulation that was significantly greater after dual-probe treatments. Conclusion: Ablation zones that were approximately four times larger than those produced by previously described percutaneous techniques delayed the growth of metastases, reduced serum CEA concentration, and induced detectable inflammatory and T-lymphocyte responses. Percutaneous cryotherapy for treatment of colorectal liver metastases is feasible and may have a place in conjunction with chemotherapy. © 2002 British Journal of Surgery Society Ltd