What is a safe future liver remnant size in patients undergoing major hepatectomy for colorectal liver metastases and treated by intensive preoperative chemotherapy?

BACKGROUND: A multidisciplinary approach involving preoperative chemotherapy has become common practice in patients with colorectal liver metastases (CLM). The definition of a safe future liver remnant (FLR) volume based on preoperative clinical data in these patients is lacking. Our aim was to identify predictors of postoperative morbidities in patients undergoing major hepatectomy after intensive preoperative chemotherapy for CLM.
METHODS: Between January 2000 and August 2010, a total of 101 consecutive patients with CLM underwent major hepatectomy after preoperative chemotherapy (≥6 cycles of oxaliplatin or irinotecan regimen with or without targeted therapies). The FLR ratio was calculated by two formulas: actual FLR (aFLR) ratio, and standardized FLR (sFLR) ratio. Predictors of postoperative overall morbidity, sepsis, and liver failure were identified by univariate and multivariate analyses.
RESULTS: Fifty-eight patients (57.4%) had 95 postoperative complications. Sepsis and postoperative liver failure occurred in 23 (22.8%) and 16 patients (15.8%), respectively. On univariate analysis, small aFLR ratio was significantly associated with all complications, and sFLR ratio was associated with sepsis and liver failure. In receiver-operating characteristic analysis, the cutoff of aFLR ratio in predicting overall morbidity, sepsis, and liver failure was 44.8, 43.1, and 37.7%, respectively, and that of sFLR ratio in predicting sepsis and liver failure was 43.6 and 48.5%, respectively. On multivariate analysis, these aFLR and sFLR ratio cutoffs were independent predictors of all complications and of sepsis and liver failure, respectively.
CONCLUSIONS: This study provides a cutoff FLR ratio for safe postoperative outcome after major hepatectomy in CLM patients receiving six or more cycles of preoperative chemotherapy.