Critical review of the prognostic significance of pathological variables in patients undergoing resection for colorectal liver metastases.

OBJECTIVE: The aim of this study was to identify prognostic factors, particularly pathological variables, that influence disease-free and overall survival following resection for colorectal liver metastases (CRLM). METHODS: Patients undergoing CRLM resection from January 2005 to December 2011 were included. Data analysed included information on demographics, laboratory results, operative findings, histopathological features and survival. RESULTS: A total of 259 patients were included. Of these, 138 (53.3%) patients developed recurrent disease, of which 95 died. The median length of follow-up in the remaining patients was 28 months (range: 12-96 months). There were significant associations between recurrence and higher tumour number (P = 0.002), presence of perineural invasion (P = 0.009) and positive margin (R1) resection (P = 0.002). Multivariate analysis showed all three prognostic factors to be independent predictors of disease-free survival. Significantly poorer overall survival after hepatic resection for CRLM was observed in patients undergoing hemi-hepatectomy or more radical resection (P = 0.021), patients with a higher number of tumours (P = 0.024) and patients with perineural invasion (P < 0.001). Multivariate analysis showed perineural invasion to be the only independent predictor of overall survival. CONCLUSIONS: The presence of perineural invasion, multiple tumours and an R1 margin were associated with recurrent disease. Perineural invasion was also an independent prognostic factor with respect to overall survival.