Outcome of microscopic incomplete resection (R1) of colorectal liver metastases in the era of neoadjuvant chemotherapy

Background. Data from patients with colorectal liver metastases (CRLM) who received neoadjuvant chemotherapy before resection were reviewed and evaluated to see whether neoadjuvant chemotherapy influences the predictive outcome of R1 resections (margin is 0 mm) in patients with CRLM. Methods. Between January 2000 and December 2008, all consecutive patients undergoing liver resection for CRLM were analyzed. Patients were divided into those who did and did not receive neoadjuvant chemotherapy. The outcome after R0 (tumor-free margin >0 mm) and R1 (tumor-free margin 0 mm) resection was compared. Results. A total of 264 were eligible for analysis. Median follow-up was 34 months. Patients without chemotherapy showed a significant difference in median disease-free survival (DFS) after R0 or R1 resection: 17 [95% confidence interval (CI) 10-24] months versus 8 (95% CI 4-12) months (P<0.001), whereas in patients with neoadjuvant chemotherapy the difference in DFS between R0 and R1 resection was not significant: 18 (95% CI 10-26) months versus 9 (95% CI 0-20) months (P = 0.303). Patients without chemotherapy showed a significant difference in median overall survival (OS) after R0 or R1 resection: 53 (95% CI 40-66) months versus 30 (95% CI 13-47) months (P\0.001). In patients with neoadjuvant chemotherapy, the median OS showed no significant difference: 65 (95% CI 39-92) months for the R0 group versus the R1 group, in whom the median OS was not reached (P = 0.645). Conclusions. In patients treated with neoadjuvant chemotherapy, R1 resection was of no predictive value for DFS and OS.