Preoperative systemic inflammation response index is an independent prognostic marker for BCG immunotherapy in patients with non‐muscle‐invasive bladder cancer

BACKGROUND: The Systemic Inflammatory Response Index (SIRI) is a novel prognostic biomarker based on peripheral blood counts of neutrophils, monocytes, and lymphocytes. Recent evidence suggests that it is associated with poor prognosis in various cancers. However, the predictive value of the SIRI in non‐muscle‐invasive bladder cancer (NMIBC) patients treated with intravesical Bacillus Calmette‐Guerin (BCG) immunotherapy remains elusive. Therefore, this study aimed to evaluate the potential of SIRI as a prognostic factor in these patients. METHODS: A total of 540 patients with NMIBC who underwent BCG immunotherapy following transurethral resection of bladder tumor (TURBT) were enrolled in this study. Using receiver operating characteristic (ROC) curves and the Youden index, patients were divided into high and low SIRI groups based on the cutoff values. Univariable and multivariable logistic regression analyses were performed to identify independent predictors of BCG non‐response. Thereafter, propensity score matching (PSM) was used to eliminate bias due to confounding factors between the low and high SIRI groups. Finally, the Kaplan–Meier method was used to compare recurrence‐free survival (RFS) and progression‐free survival (PFS) between the two groups. RESULTS: Multivariable logistic regression analysis revealed that high SIRI (p = 0.001), high MLR (p = 0.015), and high tumor pathological T stage (p = 0.015) were significantly correlated with non‐response to BCG therapy. In addition, both RFS and PFS were shorter in the high SIRI group than in the other group before and after PSM (both p < 0.05). Collectively, our results indicate that the combination of tumor pathological T staging and the SIRI can enhance the predictive power of BCG response. CONCLUSION: Pretreatment peripheral blood SIRI can be employed to predict the response to BCG immunotherapy and the prognosis of NMIBC patients. Taken together, the combination of T stage and SIRI demonstrated robust performance in predicting the response to BCG immunotherapy in NMIBC patients.