Postoperative adjuvant treatment strategy for hepatocellular carcinoma with microvascular invasion: a non-randomized interventional clinical study.

Background: Microvascular invasion (MVI) is considered to be one of the important prognostic factors that affect postoperative recurrence in patients with hepatocellular carcinoma (HCC) with variable results across their treatment options. This study was carried out to investigate efficacy of postoperative adjuvant RT in HCC patients with MVI.

Methods: This was single center, prospective study carried out in HCC patients with MVI, aged 35-72 years. All patients were non-randomly allocated to receive standard postoperative treatment of HBV/HCV and nutritional therapy or RT in addition to standard postoperative treatment (1:1). The primary endpoints assessed were relapse-free survival and overall survival. The prognostic factors associated with survival outcomes were also analyzed. The safety events were graded according to NCI-CTCAE v4.03 criteria.

Results: Of the 115 patients eligible for study, 59 patients were included in analysis. Univariate analysis revealed that MVI classification (P = 0.009), post-operative treatment strategies (P = 0.009) were prognostic factors for worst RFS; tumor size (P = 0.011), MVI classification (P = 0.005) and post-operative treatment (P = 0.015) were associated for OS. The 1-, 2-, 3-year RFS rates were 86.2, 70.5 and 63.4% for patients in RT group, and 46.4, 36.1, and 36.1% in control group. For OS, corresponding rates were 96.6, 80.7, and 80.7% for patients in RT group and 79.7, 58.3, and 50.0% in control group. Subgroup classification of HCC patients according to low risk MVI showed significantly longer RFS (P = 0.035) and OS (P = 0.004) in RT group than control group, while for high risk MVI, RT depicted longer OS than control group with no significance (P = 0.106). Toxicities were usually observed in acute stage with no grade 4 toxicities.

Conclusion: Postoperative adjuvant RT following hepatectomy offers better RFS for HCC patients with MVI than with standard postoperative therapy. Also, it will be useful to control microscopic lesions in both M1 (low risk) and M2 (high risk) subgroups of HCC patients with MVI.

Trial Registration: Trial Registration number: ChiCTR1800017371 . Date of Registration: 2018-07-26. Registration Status: Retrospectively registered.