Preoperative systemic immune-inflammation index as a significant prognostic factor after TURBT in patients with non-muscle-invasive bladder cancer: A retrospective study based on propensity score matching analysis.

OBJECTIVE: To investigate the association of the preoperative systemic immune-inflammation index (SII) with recurrence-free survival (RFS) after transurethral resection of the bladder tumor (TURBT) of non-muscle-invasive bladder cancer (NMIBC) using propensity score matching (PSM) analysis. METHODS: The clinicopathological characteristics and follow-up data of NMIBC patients were collected retrospectively from two tertiary medical centers. A 1:1 PSM analysis was carried out using the nearest-neighbor method (caliper size: 0.02). Cox regression analysis was used to identify the risk factors associated with RFS. RESULTS: A total of 416 NMIBC patients were included in this study. Before and after matching, patients with increased SII had worse RFS (p < 0.0001 and p = 0.027, respectively). Multivariate Cox analysis identified SII as an independent predictor of RFS before (HR [95% CI]: 1.789 [1.232, 2.599], p = 0.002) and after matching (HR [95% CI]: 1.646 [1.077, 2.515], p = 0.021). In the matched subgroup analysis, an elevated SII had a significant association with postoperative worse RFS in the T1 stage (p = 0.025), primary status (p = 0.049), high-grade (p = 0.0015), and multiple lesions (p = 0.043) subgroups. CONCLUSION: SII could accurately stratify the prognosis of NMIBC patients before and after PSM analysis. An elevated SII was significantly associated with worse RFS in NMIBC patients.