Background : The effect of the resection margin on surgical outcomes in hepatocellular carcinoma (HCC) patients with microvascular invasion (MVI) remains in debate. This study aims to investigate whether sub-classification of MVI affects the impact of resection margin width on surgical prognosis for solitary HCC patients after curative liver resection.

Methods : MVI status of HCC patients who underwent hepatectomy in our Hospital between May 2018 and December 2019 was further divided into no vascular invasion (NVI), microvessel invasion (MI) and microscopic portal vein invasion (MPVI). The impact of resection margin width on progression-free survival (PFS) and overall survival (OS) for HCC patients with different MVI status and the factors influencing postoperative prognosis were all evaluated.

Results : MVI was identified histologically in 133 patients (22.1%). The 3-year OS and RFS rates of the patients in the NVI, MI and MPVI group were 87.4%, 70.2%, 53.9% and 59.5%, 47.7%, 29.9%, respectively (p<0.0001). Wide resection margin (≥1cm) resulted in better 3-year recurrence and overall survival versus a narrow resection margin (<1cm) among patients with MI (64.5% versus 23.7%; 80.7% versus 50.0%; both p<0.05). However, wide resection margin did not improve the surgical outcomes in patients in the NVI and MPVI group. Multivariate analysis indicated that tumor size, MI and MPVI were the independent risk factors affecting RFS and OS after curative liver resection.

Conclusions : Wide resection margin could improve the surgical outcomes after curative liver resection for patients with MI. For patients with MPVI and without NVI, resection margin width did not influence the long-term outcomes after hepatectomy.