Prognostic impact of positive surgical margins after resection of colorectal cancer liver metastases: reappraisal in the era of modern chemotherapy.

Background: The purpose of the present study was to assess the prognostic impact of positive surgical margins (R1) after liver resection (LR) of colorectal liver metastases (CRLM) in the era of modern chemotherapy regimens. R1 resection is a negative prognostic factor after LR of CRLM. The significance of R1 margins in the era of effective chemotherapy is unknown.

Methods: From January 2000 to December 2009, 215 patients (177 men: 62 %; median age 60 years; range 30-84 years) underwent LR of CRLM. The LR was considered R1 (margin <1 mm) in 49 patients (23 %) and R0 in 166 patients (77 %). Overall, 108 (50 %) patients received preoperative chemotherapy and 156 (72 %) patients received postoperative chemotherapy.

Results: With a median follow-up of 36 months (range 1-141 months), the 5-year overall survival (OS) rate (47 vs 40 %; p = 0.05) and the disease-free survival (DFS) rate (36 vs 23 %; p = 0.006) were significantly lower in the R1 group. Recurrence developed in 152 patients (71 %) and the rate of recurrence was significantly higher (84 vs 67 %; p = 0.02) in the R1 group. On multivariate analysis, N+ status of the colorectal primary tumor (p = 0.008), presence of radiologically occult disease (p = 0.04), and R1 resection (p = 0.03) were independent adverse predictors of OS. The N+ status of the primary tumor (p = 0.003) and R1 resection (p = 0.02) were independent adverse predictors of DFS. On multivariate analysis use of postoperative chemotherapy was the only independent predictor of improved DFS (p = 0.02) in the R1 group.

Conclusions: A positive resection margin remains a significant poor prognostic factor after LR of CRLM in the era of modern chemotherapy. Postoperative chemotherapy reduces recurrence rates after R1 resection of CRLM.