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The impact of portal pedicle clamping on survival from colorectal liver metastases in the contemporary era of liver resection: a matched cohort study.

INTRODUCTION
Portal pedicle clamping (PPC) may impact micro-metastases' growth. This study examined the association between PPC and survival after a hepatectomy for colorectal liver metastases (CRLM).


METHODS
A matched cohort study was conducted on hepatectomies for CRLM at a single institution (2003-2012). Cohorts were selected based on PPC use, with 1:1 matching for age, time period and the Clinical Risk Score. Outcomes were overall and recurrence-free survival (OS and RFS). Cox regression was performed to assess the association between PPC and survival.


RESULTS
Of 481 hepatectomies, 26.9% used PPC. One hundred and ten pairs of patients were matched in the cohorts. There was no significant difference in OS [hazard ratio (HR) 1.18; 95% confidence interval (CI): 0.76-1.83], with a 5-year OS of 57.8% (95%CI: 52.4-63.2%) with PPC versus 62.3% (95%CI: 57.1-67.5%) without. Five-year RFS did not differ (HR 0.98; 95%CI: 0.71-1.35) with 29.7% (95%CI: 24.9-34.5%) with PPC versus 28.0% (95%CI: 23.2-32.8%) without. When adjusting for extent of resection, transfusion, operative time and surgeon, there was no difference in OS (HR 0.91; 95%CI: 0.52-1.60) or RFS (HR: 0.86; 95%CI: 0.57-1.30).


CONCLUSIONS
PPC was not associated with a significant difference in OS or RFS in a hepatectomy for CRLM. PPC remains a safe technique during hepatectomy.