LAUSR

Background. Occasionally, right hepatectomy, rather than parenchyma‐preserving hepatectomy, has been performed for solitary small colorectal liver metastasis. The relative oncologic benefits of parenchyma‐preserving hepatectomy and right hepatectomy are unclear. This study compared the outcomes of patients with solitary small colorectal liver metastasis in the right liver who underwent parenchyma‐preserving hepatectomy and those who underwent right hepatectomy. Methods. The study population consisted of a multicentric cohort of 21,072 patients operated for colorectal liver metastasis between 2000 and 2015 whose data were collected in the LiverMetSurvey registry. Patients with a pathologically confirmed solitary tumor of less than 30 mm in size in the right liver were included. The short‐ and long‐term outcomes of patients who underwent parenchyma‐preserving hepatectomy were compared to those of patients who underwent right hepatectomy. Results. Of the 1,720 patients who were eligible for the study, 1,478 (86%) underwent parenchyma‐preserving hepatectomy and 242 (14%) underwent right hepatectomy. The parenchyma‐preserving hepatectomy group was associated with lower rates of major complications (3% vs 10%; P < .001) and 90‐day mortality (1% vs 3%; P = .008). Liver recurrence occurred similarly in both groups (20% vs 22%; P = .39). The 5‐year recurrence‐free survival and overall survival rates were similar in both groups. However, in patients with liver‐only recurrence, repeat hepatectomy was more frequently performed in the parenchyma‐preserving hepatectomy group than in the right hepatectomy group (67% vs 31%; P < .001), and the overall 5‐year survival rate was significantly higher in the parenchyma‐preserving hepatectomy group than in the right hepatectomy group (55% vs 23%; P < .001). Conclusion. Parenchyma‐preserving hepatectomy should be considered the standard procedure for solitary small colorectal liver metastasis in the right liver when technically feasible.