Interaction of tumour biology and tumour burden in determining outcome after hepatic resection for colorectal metastases

Aims: To determine the outcome of colorectal liver metastasis (CRLM) patients based on tumour burden, represented by tumour number and size, and tumour biology as assessed by an inflammatory response to tumour (IRT) and margin positivity. Methods: Data were collated from CRLM patients undergoing resection from January 1993 to March 2007. Patients were divided into: low (<= 3 metastases and/or <= 3 cm); moderate (4-7 metastases and/or >3-<= 5 cm); and high (>= 8 metastases and/or >5 cm) tumour burden. Results: Seven hundred and five patients underwent resection, of which 154 (21.8%), 262 (37.2%) and 289 (41.0%) patients were in the low, moderate and high tumour burden groups, respectively. The 5-year disease-free (P < 0.001) and overall (P < 0.001) survival were significantly different between the groups. IRT (P < 0.001), extent of resection (P < 0.001) and margin (P < 0.001) also differed between the groups. Sub-group analysis revealed that IRT was the only adverse predictor for disease-free and overall survival in the low group. In the moderate group, IRT predicted poorer disease-free survival on multivariate analysis. In the high group, R1 resection and transfusion were predictors of poorer disease-free survival and age >= 65 years, R1 resection and IRT were adverse predictors of overall survival. Conclusion: Resection margin influenced the outcome of patients with high tumour burden, hence the importance of achieving clear margins. IRT influenced the outcome of patients with less aggressive disease.