Introduction : Increasingly, patients with multiple colorectal liver metastases (CRLM) are surgically treated. R1par surgery remains one of the negative prognostic factors for overall survival(OS). According to our data on R1 in main intrahepatic vascular contact (MVC) ,we investigate the oncological outcome of patients with multiple bilobar disease with bilateral MVC (BC), compared to patients with unilateral MVC (UC) and patients with disease and no MVC (NC).

Methods : This single-institution study included patients who underwent hepatectomy for multiple (≥4) bilobar CRLM lesions from 2004-2019. Three-hundred-fifty-five patients meet the inclusion criteria. One-hundred-thirty-two patients with R1par resection were excluded. Three groups were defined: NC, UC, BC. After pairwise propensity score match 145 patients were analyzed.

Results : No differences between groups were observed in the preoperative variables. Increased surgical time, hilar clamping, and blood loss were reported in the BC group. Postoperative minor morbidity, liver failure rate, overall and local recurrences were higher in the BC group. BC patients were more likely to be re-resected. Cumulative OS 3-5 years survival in NC, UC, BC were 54%- 40%, 49% - 35%, 57%-24% (p <0.91). At multivariate analysis, factors influencing OS, were N status of the primitive lesions, RAS status, and repeated hepatectomy.

Conclusions : Patients with BC and lesions ≥ 4 are generally considered unresectable or suitable for staged hepatectomy. This retrospective study shows that these patients can be submitted to the so called enhanced-one-staged hepatectomy with the same oncological results, however surgical complexity, postoperative minor morbidity and postoperative liver failure are increased.