The impact of R1 resection for colorectal liver metastases on local recurrence and overall survival in the era of modern chemotherapy: An analysis of 1,428 resection areas.

BACKGROUND: It is still unclear whether a positive surgical margin after resection of colorectal liver metastases remains a poor prognostic factor in the era of modern perioperative chemotherapy. The aim of this study was to evaluate whether preoperative chemotherapy has an impact on reducing local recurrence after R1 resection, and the impact of local recurrence on overall survival. METHODS: Between 2000 and 2014, a total of 421 patients underwent resection for colorectal liver metastases at our unit after preoperative chemotherapy. The overall number of analyzed resection areas was 1,428. RESULTS: The local recurrence rate was 12.8%, significantly higher after R1 resection than after R0 (24.5% vs 8.7%; P < .001). These results were also confirmed in patients with response to preoperative chemotherapy (23.1% after R1 vs 11.2% after R0; P < .001). At multivariate analysis, R1 resection was the only independent risk factor for local recurrence (P < .001). At the analysis of the 1,428 resection areas, local recurrence significantly decreased according to the increase of the surgical margin width (from 19.1% in 0 mm margin to 2.4% in ≥10 mm). At multivariable logistic regression analysis for overall survival, the presence of local recurrence showed a significant negative impact on 5-year overall survival (P < .001). CONCLUSION: Surgical margin recurrence after modern preoperative chemotherapy for colorectal liver metastases was still significantly higher after R1 resection than it was after R0 resection. Local recurrence showed a negative prognostic impact on overall survival. R0 resection should be recommended whenever technically achievable, as well as in patients treated by modern preoperative chemotherapy.