PURPOSE:It frequently is observed that widely varying prognoses are given for patients with the same extent of liver metastases from colorectal cancer, even though the same treatment is performed on these patients. One of the reasons for this variance is that prognostic factors for these patients have not been defined. This study was designed to elucidate which clinicopathologic factors were the most important in the prognosis of 73 patients with unresectable synchronous liver metastasis from colorectal cancer.METHODS:Univariate and multivariate analysis of 11 clinicopathologic factors were performed using the Cox proportional hazard model. Survival curves were generated using the Kaplan‐Meier method.RESULTS:Extent of liver metastases was the most significant variable in this survival analysis, although the extent of lymph node metastases of the primary lesion also was significant. However, the method of treatment was not a significant determinant in the survival for patients with unresectable liver metastases. Median survival of patients with H1, H2, and H3was 13, 12, and 6 months, respectively, and there was a significant difference between survival curves for patients with H1and patients with H3. Median survival of patients with n0, n1and n2was 13, 7, and 7 months respectively, and there was a significant difference between survival curves for patients with n0and patients with n2. Median survival of 6 patients with H1and n0and of 17 patients with H3and n2was 28 and 4 months, respectively. There was a significant difference in survival curves between these two groups.CONCLUSION:Longevity of patients with unresectable synchronous liver metastases from colorectal cancer is affected adversely by the presence of nodal metastases and extent of liver metastases. This should be considered in the planning treatment.