Preoperative chemotherapy and resection margin status in colorectal liver metastasis patients: A propensity score-matched analysis

In this article, we compared the early and long-term outcomes of patients with metastatic colorectal cancer treated with chemotherapy followed by resection with those of patients undergoing surgery first, focusing our analysis on resection margin status. Patients who underwent liver resection with curative intent for colorectal liver metastases from July 2001 to January 2018 were included in the analysis. Propensity score matching was used to reduce treatment allocation bias. The cohort comprised 164 patients; 117 (71.3%) underwent liver resection first, whereas the remaining 47 (28.7%) had preoperative chemotherapy. After a 1:1 ratio of propensity score matching, 47 patients per group were evaluated. A positive resection margin was found in 13 patients in the surgery-first group (25.5%) versus 4 (8.5%) in the preoperative chemotherapy group (P = 0.029). Postmatched logistic regression analysis showed that only preoperative chemotherapy was significantly associated with the rate of positive resection margin (odds ratio 0.24, 95% confidence interval 0.07-0.81; P = 0.022). Median follow-up was 41 months (interquartile range 8-69). Cox proportional hazard regression analysis revealed that only positive resection margin was a significant negative prognostic factor (hazard ratio 2.2, 95% CI 1.18-4.11; P = 0.014). Within the preoperative chemotherapy group, median overall survival was 40 months in R0 patients and 10 months in R1 patients (P = 0.016). Although preoperative chemotherapy in colorectal liver metastasis patients may affect the rate of positive resection margin, its impact on survival seems to be limited. In the present study, the most important prognostic factor was the resection margin status.