The prognostic value of systemic immune-inflammation index in patients with unresectable hepatocellular carcinoma treated with immune-based therapy

This study evaluates the Systemic Immune-Inflammation Index (SII) for predicting immune-based therapy response and prognosis in unresectable hepatocellular carcinoma (HCC) patients.A cohort of 268 HCC patients treated with immune-based therapy from January 2019 to March 2023 was studied. The training group of 93 patients received atezolizumab plus bevacizumab (T+A) treatment, while 175 patients in the validation group were treated with tyrosine kinase inhibitors (TKIs) and anti-PD-(L)1 therapy. SII’s cutoff point was determined using X-tile analysis based on overall survival (OS) in the training cohort. Prognostic factors were identified through univariate and multivariate logistic and Cox regression analyses, with survival outcomes compared using Kaplan-Meier methods. The predictive accuracy of SII was assessed using receiver operating characteristic (ROC) curves. The optimal cutoff for SII was 752*10 ⁹ . Univariate and multivariate logistic regression indicated that SII was a strong predictor for the objective response rate (ORR). The ORR was significantly different between the low SII and high SII subgroups (34.72% vs. 9.52%, P = 0.019), similar results were validated in the validation group (34.09% vs. 16.28%, P = 0.026). SII also demonstrated prognostic significance in Cox regression and Kaplan-Meier analyses. ROC curves showed that the SII’s predictive function was superior among common clinical indicators, with relevance even in AFP-negative patients. Lower SII was associated with a higher T cell ratio, higher CD8 ⁺ T cell and GranzymeB ⁺ CD8 ⁺ T cell number in peripheral blood. SII is a viable predictor of the efficacy and prognosis of various kinds of immune-based therapy in HCC patients, potentially serving aiding therapeutic decisions, thus increasing the likelihood of patients benefiting from immune-based therapy.