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

Background The prognosis impact of positive margins after resection of colorectal liver metastases (CLM) in patients treated with modern effective chemotherapy has not been elucidated. The objective was to compare oncologic outcomes after R0 and R1 resections in the era of modern effective chemotherapy. Methods Between 1999 and 2010, all consecutive patients undergoing liver resection for CLM were analyzed retrospectively. Patients with extrahepatic metastases, macroscopic residual tumor, treated with combined radiofrequency, or not treated with chemotherapy were excluded. Survival and recurrence after R0 (tumor-free margin >0 mm) and R1 resections were analyzed. Results Among 466 patients 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 patients treated or not by preoperative chemotherapy. R1 status was associated with more intrahepatic recurrences. Overall survival (OS) (44 vs. 61 %; p = 0.047) and disease-free survival (DFS) (8 vs. 26 %; p = 0.082) were lower in patients 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 patients treated with preoperative chemotherapy, OS 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 era of modern effective chemotherapy, R1 resection leads to more intrahepatic recurrences but did not affect OS in selected patient responders to neoadjuvant chemotherapy. Postoperative chemotherapy protects from recurrences whatever the margin resection status.