The impact of resection margin and microvascular invasion on long-term prognosis after curative resection of hepatocellular carcinoma: a multi-institutional study

Background: The resection margin (RM) status and microscopic vascular invasion (MVI) are known prognostic factors for hepatocellular carcinoma (HCC). An enhanced understanding of their impact on long-term prognosis is required to improve oncological outcomes. Methods: Using multi-institutional data, the different impact of the RM status (narrow, <1 cm, or wide, >= 1 cm) and MVI (positive or negative) on overall survival (OS) and recurrence-free survival (RFS) after curative liver resection of solitary HCC without macrovascular invasion was analyzed. Results: In 801 patients, 306 (38%) had a narrow RM and 352 (44%) had positive MVI. The median OS and RFS were 109.8 and 74.8 months in patients with wide RM & negative MVI, 93.5 and 53.1 months with wide RM & positive MVI, 79.2 and 41.6 months with narrow RM & negative MVI, and 69.2 and 37.5 months with narrow RM & positive MVI (both P < 0.01). On multivariable analyses, narrow RM & positive MVI had the highest hazard ratio with reduced OS and RFS (HR 2.96, 95% CI 2.11-4.17, and HR 3.15, 95% CI, 2.09-4.67, respectively). Conclusions: Concomitant having narrow RM and positive MVI increases the risks of postoperative death and recurrence by about 2-fold in patients with solitary HCC.