Objective: The authors defined a new macroscopic classification of liver metastases from colorectal cancer.
Summary background data: There were different prognostic results after the same operative procedure for liver metastases with similar background factors.
Methods: Eighty-one resected liver metastases were classified into simple nodular (SN) or confluent nodular (CN) types according to the characteristics of the cut surface of the tumor.
Results: The 5-year survival rates after hepatectomy were 41.7% for the SN lesions (n = 39) and 23.1% for the CN lesions (n = 42). The difference between the survival curves was statistically significant (p = 0.0307). Multivariate analysis using Cox's proportional hazards model revealed that the macroscopic type (p = 0.023), the tumor diameter (p = 0.0001), and the presence of lymph node metastases (p = 0.0016) were statistically significant independent prognostic factors.
Conclusion: The new macroscopic classification may be valuable as a prognostic factor reflecting the biologic behavior of liver metastases.