Outcomes of sarcomatoid hepatocellular carcinoma patients treated with immunotherapy: A multi-institutional retrospective study.

569 Background: Sarcomatoid hepatocellular carcinoma (sHCC) is a rare and aggressive variant of HCC with poor prognosis. Because of its low incidence and exclusion from pivotal trials, the efficacy of immune checkpoint inhibitors (ICI) remains unclear. We conducted a multi-institutional retrospective study through the Taiwan Liver Cancer Association Research Group (TRG) to evaluate outcomes of sHCC patients treated with ICI-based regimens. Methods: Patients with pathologically confirmed sHCC diagnosed between 2017/01/01 and 2024/12/31 were identified across referral centers in Taiwan. Demographic, clinicopathologic, treatment, and outcome data were collected. Patients were categorized into curative resection, systemic therapy, and supportive care groups. Overall survival (OS) was defined from diagnosis to death or last follow-up. Among systemic therapy recipients, OS was compared between ICI, tyrosine kinase inhibitors (TKIs: sorafenib or lenvatinib), and chemotherapy. Results: Seventy-two patients with sHCC were identified. Nine underwent curative resection without recurrence. The remaining 63 either recurred or were unresectable. In this cohort (N=63), median age was 65 years; 71.4% were male, 33.3% had HBV, 20.6% had HCV, 92.1% were Child–Pugh A, 42.9% had macrovascular invasion, and 68.3% had extrahepatic metastasis. Twenty received supportive care (median OS 6.75 months), and 43 received systemic therapy (median OS 11.19 months). The overall median OS of the recurred/unresectable cohort was 10.01 months. Within systemic therapy, 13 patients received ICI-based regimens (median OS 14.35 months), 15 received sorafenib/lenvatinib (7.56 months), and 15 received chemotherapy (10.77 months). Baseline characteristics were comparable across groups. ICI therapy was associated with significantly longer OS than TKIs, and numerically but not statistically superior OS compared with chemotherapy. Conclusions: This multi-institutional analysis represents one of the largest real-world cohorts of sHCC. ICI-based therapy demonstrated meaningful survival benefit over sorafenib/lenvatinib and numerically improved survival over chemotherapy. Despite the aggressive biology of sHCC, immunotherapy may offer a rational treatment option. Prospective validation in larger datasets is warranted. Clinical outcomes of patients with sarcomatoid HCC. Treatment group N Median OS (months) Resection, no recurrence 9 Not reached Recurrence/unresectable cohort 63 10.01 Supportive care only 20 6.75 Systemic therapy 43 11.19 ICI-containing regimen 13 14.35 Sorafenib/Lenvatinib 15 7.56 Chemotherapy 15 10.77