Differential Prognostic Impacts of Hepatic Segment VI and VII Involvement in Hepatocellular Carcinoma.

Abstract

This study aimed to investigate the impact of hepatic segment distribution on the prognosis of patients with primary hepatocellular carcinoma (HCC). A retrospective analysis was conducted on 456 eligible patients with primary HCC admitted to the Hepatobiliary Surgery Department of Cancer Hospital, Chinese Academy of Medical Sciences, from January 2013 to December 2017. Tumor hepatic segment location was confirmed by postoperative pathology or imaging examinations, and clinical data (e.g. age, surgical method, operation time) were collected from the HIS electronic medical record system. Follow-up ended on May 5, 2019, with overall survival (OS) as the primary endpoint. Results showed that most tumors (70.39%, 321/456) were located in the right hemi-liver, with the highest incidence in Segment VI (53.73%, 245/456) and Segment VII (46.05%, 210/456). Univariate analysis identified tumor diameter, tumor characteristics, surgical method, operation time, intraoperative blood loss, and hepatic segment location as factors associated with OS. Multivariate COX analysis revealed that tumor diameter, open surgery, and intraoperative blood loss were independent predictors of poor long-term prognosis. Notably, hepatic segment location exerted contrasting effects: Segment VI tumors independently associated with poorer prognosis (HR=2.04, 95% CI=1.11-3.74, p=0.021), while Segment VII tumors served as a significant survival benefit (HR=0.47, 95% CI=0.25-0.88, p=0.018). Further subgroup analysis indicated that the protective effect of Segment VII was more pronounced in tumors ≥6 cm (p=0.03), whereas for tumors <6 cm, Segment VII involvement had no significant prognostic impact (p=0.32). For Segment VI tumors, laparotomy was associated with poorer prognosis regardless of tumor size (<6 cm: p=0.029; ≥6 cm: p=0.039), a trend not observed in non-Segment VI tumors ≥6 cm (p=0.9). Hepatic segment distribution is an independent prognostic indicator and may serve as a surrogate marker reflecting tumor biology, surgical complexity, and treatment selection, rather than an independent causal determinant, with Segment VI and VII showing distinct prognostic roles: Segment VI involvement is associated with worse survival, while Segment VII involvement confers a survival benefit. These findings provide valuable insights for precision surgical decision-making in HCC, such as prioritizing minimally invasive approaches or neoadjuvant therapy for Segment VI tumors and considering de-escalated treatment for large Segment VII tumors. Future studies should explore the molecular and immune mechanisms underlying these segment-specific differences and validate the results through multicenter prospective trials.