Preoperative HAIC enlarges future liver remnant in initial unresectable HCC patients with Vp3 tumor thrombus

Background Conversion strategy is the optimal treatment for patients with unresectable hepatocellular carcinoma (uHCC). However, a severe lack of future liver remnant (FLR) may result in early withdrawal. In this small sample retrospective study, we investigated FLR changes after conversion therapies. Notably, patients with ipsilateral Vp3 portal vein tumor thrombus (PVTT) showed a significant FLR increase after treatment and provided an advantage for carrying out radical surgery. Methods 53 uHCC patients with Vp0 to Vp3 tumor thrombus were enrolled and divided into two groups (Vp0–2 and Vp3) based on the initial PVTT status. All patients received anti-PD-L1 and anti-VEGF therapy combined with hepatic arterial infusion chemotherapy (HAIC) every three weeks. The FLR was measured at baseline and after 3–4 cycles. The odds ratio (OR) between Vp3 and FLR changes was calculated. Results Among the 53 patients, 28 achieved complete response (CR) or partial response (PR) after conversion treatment. FLR did not change in Vp0–2 group, regardless of the response. While a significant FLR increase was observed in Vp3 group, especially in patients with CR and PR. 10 cases of successfully converted Vp3 patients showed an average FLR enlargement of 18.5%. Conclusion According to our study, Vp3 patients demonstrated greater FLR enlargement after conversion therapy combined with HAIC, probably due to the thrombus’ restriction on blood flow to the tumor side liver. This observation may help to increase both the surgeons’ and the uHCC patients’ confidence in continuing treatment.