R1 resection of colorectal liver metastasis - What is the cost of marginal resection?

BACKGROUND AND OBJECTIVES

The impact of resection margins on the outcome of patients with colorectal liver metastasis (CRLM) remains controversial. We evaluated the short and long-term results of R1 resection.

METHODS

Between 2006 and 2016, 202 patients underwent liver resection for CRLM. R1 resection was defined as a distance of less than 1 mm between tumor cells and the transection plain. Patient and tumor characteristics, perioperative, and long-term outcomes were assessed.

RESULTS

In 161 (79.7%) and 41 (20.3%) patients, an R0 and R1 resections were achieved, respectively. Patients that underwent an R1 resection had higher rates of disease progression while on chemotherapy (12.1% vs 5.5%, P = 0.001), need for second-line chemotherapy (17% vs 6.2%, P < 0.001), increased use of preoperative volume manipulation (14.6% vs 5.5%, P = 0.001), and inferior vena-cava involvement (21.9% vs 8.7%, P < 0.001). These patients had higher rates of major postoperative complications (19.5% vs 6.8%, P < 0.001) and reoperations (7.3% vs 2.4%, P < 0.001). Multivariate analysis demonstrated that R1 resections were not associated with decreased recurrence-free survival or overall survival.

CONCLUSIONS

Although R1 resection is associated with worse disease behavior and postoperative complications, the long-term outcome of patients following an R1 resection is non-inferior to those who underwent an R0 resection.