BACKGROUND:Two-stage hepatectomy of bilobar colorectal liver metastases is widely used and shows encouraging survival results. However, the risk of dropout after the first stage remains high and is associated with poor survival. The objective of our study was to evaluate the factors associated with long-term survival based on the pathologic response to preoperative systemic chemotherapy in colorectal liver metastases patients who underwent two-stage hepatectomy.METHODS:The pathologic response to preoperative chemotherapy and its effect on second-stage completion and survival were retrospectively evaluated in 67 patients treated between 2003 and 2013.RESULTS:A total of 56 patients underwent two-stage hepatectomy for initially nonresectable colorectal liver metastases. Chemotherapy was combined with a biotherapy in 32 cases. The tumor regression grade, modified tumor regression grade, and Blazer grade were used to classify patients as responders (tumor regression grade and modified tumor regression grade 1-3, Blazer 0-1) or nonresponders (tumor regression grade and modified tumor regression grade 4-5, Blazer 2) after the first stage. Tumor response in the three classifications was associated with second-stage completion (tumor regression grade 1-3: OR = 4.01, 95% CI: 1.12-14.36, P = .033; modified tumor regression grade 1-3: OR = 3.8, 95% CI: 1.13-12.6, P = .03; Blazer 0-1: OR = 5.45, 95% CI: 1.66-17.85, P = .005). Triple chemotherapy was also associated with responders. The median overall survival of responders was significantly higher (Blazer 0-1: 42.9 months versus Blazer 2: 20.1 months, P = .018; tumor regression grade 1-3: 42.9 months versus tumor regression grade 4-5: 25.1 months, P = .04).CONCLUSION:A pathologic response to chemotherapy is associated with second-stage completion and longer survival. Further studies are needed to achieve the early identification of patients for whom the benefit of the second surgical stage is less straightforward.