Prognostic factors for cryotherapy of colorectal liver metastases

Background. Cryotherapy is a local ablative treatment option for non-resectable liver tumours. We aimed to identify prognostic indicators, that may allow better selection or stratification for adjuvant therapies of patients. Methods. Fifty-five patients had cryotherapy for colorectal liver metastases. The patient-, tumour- and operative details were recorded prospectively. Mean follow up was 24 months. A uni- and multivariate analysis for possible prognostic factors was performed. Results. There was a trend towards better survival for patients with unilobar liver metastases, preoperative serum levels of carcinoembrional antigen (CEA) not exceeding 20 ng/ml and patients undergoing ‘R0’-treatment. Patients with multiple or large (>4 cm) liver metastases, patients undergoing cryotherapy combined with liver resection and patients receiving blood transfusion intraoperatively, especially when exceeding 4 units packed red cells, had a significantly impaired survival in univariate analysis. In multivariate analysis (Cox regression) the amount of intraoperative blood transfusion was the only independent prognostic indicator. Conclusion. Intraoperative blood transfusion has a negative impact on survival following hepatic cryotherapy for colorectal liver metastases and should be avoided by refinement of surgical technique whenever possible. Patients with multiple liver metastases or metastases of more than 4 cm in size have an impaired prognosis—therefore trials of adjuvant therapies following hepatic cryotherapy for colorectal liver metastases should include number and size of metastases for stratification of patient groups.