Margin status remains an important determinant of survival after surgical resection of colorectal liver metastases in the era of modern chemotherapy.

Objective: To determine the impact of surgical margin status on overall survival (OS) of patients undergoing hepatectomy for colorectal liver metastases after modern preoperative chemotherapy.

Background: In the era of effective chemotherapy for colorectal liver metastases, the association between surgical margin status and survival has become controversial.

Methods: Clinicopathologic data and outcomes for 378 patients treated with modern preoperative chemotherapy and hepatectomy were analyzed. The effect of positive margins on OS was analyzed in relation to pathologic and computed tomography-based morphologic response to chemotherapy.

Results: Fifty-two of 378 resections (14%) were R1 resections (tumor-free margin <1 mm). The 5-year OS rates for patients with R0 resection (margin ≥1 mm) and R1 resection were 55% and 26%, respectively (P = 0.017). Multivariate analysis identified R1 resection (P = 0.03) and a minor pathologic response to chemotherapy (P = 0.002) as the 2 factors independently associated with worse survival. The survival benefit associated with negative margins (R0 vs R1 resection) was greater in patients with suboptimal morphologic response (5-year OS rate: 62% vs 11%; P = 0.007) than in patients with optimal response (3-year OS rate: 92% vs 88%; P = 0.917) and greater in patients with a minor pathologic response (5-year OS rate: 46% vs 0%; P = 0.002) than in patients with a major response (5-year OS rate: 63% vs 67%; P = 0.587).

Conclusions: In the era of modern chemotherapy, negative margins remain an important determinant of survival and should be the primary goal of surgical therapy. The impact of positive margins is most pronounced in patients with suboptimal response to systemic therapy.