BACKGROUND: The prognosis impact of positive margins after resection of colorectal liver metastases (CLM) in @entity1 treated with modern effective chemotherapy has not been elucidated. The objective was to compare oncologic outcomes after R0 and R1 resections in the @entity7971 of modern effective chemotherapy. METHODS: Between 1999 and 2010, all consecutive @entity1 undergoing liver resection for CLM were analyzed retrospectively. @entity1 with extrahepatic metastases, macroscopic @entity41 , treated with combined radiofrequency, or not treated with chemotherapy were excluded. Survival and recurrence after R0 ( @entity5 -free margin >0  mm) and R1 resections were analyzed. RESULTS: Among 466 @entity1 undergoing hepatectomy for CLM, 191 were eligible. Of them, 164 (86  %) received preoperative chemotherapy and 105 (55  %) received postoperative chemotherapy. R1 resection (10  %) was comparable in @entity1 treated or not by preoperative chemotherapy. R1 status was associated with more intrahepatic recurrences. @entity1349 ( @entity1349 ) (44 vs. 61  %; p  =  0.047) and disease-free survival (DFS) (8 vs. 26  %; p  =  0.082) were lower in @entity1 after R1 compared to R0 resection (32  months of median follow-up). Preoperative chemotherapy and major hepatectomy were prognostic factors of survival, whereas postoperative chemotherapy was a protective factor from recurrences. In @entity1 treated with preoperative chemotherapy, @entity1349 and DFS were similar between R1 and R0 resections (40 vs. 55  %, p  =  0.104 and 9 vs. 22  %, p  =  0.174, respectively). CONCLUSION: In the @entity7971 of modern effective chemotherapy, R1 resection leads to more intrahepatic recurrences but did not affect @entity1349 in selected @entity1 responders to neoadjuvant chemotherapy. Postoperative chemotherapy protects from recurrences whatever the margin resection status.

Significance of R1 Resection for Advanced Colorectal Liver Metastases in the XXXX of Modern Effective Chemotherapy.

@entity1 :: ('9606', 'Species') :: ['Patients', 'patients', 'patient'] @entity7971 :: ('26284', 'Gene') :: ['era'] @entity41 :: ('MESH:D018365', 'Disease') :: ['residual tumor'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumor'] @entity1349 :: ('MESH:D011475', 'Disease') :: ['OS', 'Overall survival']
@entity7971 :: (26284,Gene) :: ['Era']
