Intra-Tumoral Vascular Growth Patterns is a Robust Indicator of Adjuvant PD-1 Inhibitors Following Liver Resection in Hepatocellular Carcinoma: A Multicenter Cohort and Multiomics Study

Hepatocellular carcinoma (HCC) is a common malignancy worldwide, with the number of new cases and deaths increasing yearly. Curative surgery continues to be the preferred treatment for early-stage HCC. However, some early-stage HCC often experience early recurrence after surgery, and one of the most common risk factors is microvascular invasion (MVI). Nevertheless, the overall prognosis of some MVI-negative patients is also not satisfactory. Whether there are other hidden robust risk factors for recurrence is of intense interest to clinical scientists.

In contrast to the classic capillary pattern, cobweb-like pattern of vascular is present in renal cell carcinoma, thyroid follicular carcinoma and HCC. Specifically, this particular vascular pattern is a continuous lining of sinusoid-like vessels that isolate and encapsulate individual tumor clusters, and Fang et al. named it vessels that encapsulate tumor clusters (VETC). CD34 or CD31 immunohistochemical staining of tumor tissue can easily identify the vascular pattern of VETC, which can exist at any stage of HCC, accounting for about 40%-50.6%. VETC could directly invade adjacent vascular and migrate as tumor clusters instead of epithelial-mesenchymal transition pathway, which may well explain why VETC-positive HCC is closely associated with higher postoperative recurrence rate and poor prognosis. Due to the high proportion of VETC vascular patterns and poor prognosis, it is necessary to adopt effective adjuvant treatment. Zhuan et al found that unresectable VETC+HCC could benefit from treatment with sorafenib in a subsequent study. Similarly, another study found that FGF 2 and FGFR 3-4 (rather than VEGF-A or VEGFR 1-3) were high expression in VETC+ HCC, which raise the possibility that lenvatinib is a potentially effective treatment modality. Recently, a multicenter randomized controlled trial of postoperative adjuvant Sintilimab reported encouraging positive results, suggesting the possibility of its application in VETC-positive patients. Whether the combination of lenvatinib and Sintilimab can further improve the prognosis is also worth exploring.

To address these clinical challenges, the investigators conducted a multicenter study involving three surgical cohorts with postoperative active surveillance cohort(AC), adjuvant Sintilimab cohort(AS), and adjuvant Sintilimab plus Lenvatinib cohort(ASL). The cases in the AS cohort were mainly from a previous prospective cohort study initiated by the investigator's center and a later cohort expansion (NCT05307926). Moreover, multi-omics sequencing analysis aims to further explore the molecular biological characteristics between VETC positive and negative HCC.