Abstract: ObjectiveTo investigate the predictive value of preoperative systemic immune-inflammatory index (SII)
for tumor recurrence in non-invasive bladder cancer (NMIBC) patients who underwent transurethral resection of bladder
tumor (TURBT). MethodsThe clinical data of 201 patients newly diagnosed with NMIBC were retrospectively analyzed.
Clinical data such as laboratory examination and pathological results were collected. Neutrophil-to-lymphocyte ratio (NLR),
platelet-to-lymphocyte ratio (PLR) and SII were calculated based on the blood routine results one week before surgery. The
receiver operating characteristic (ROC) curves were used to compare the accuracy of the three indicators in predicting tumor
recurrence in NMIBC patients. According to the optimal cut-off value of SII, the patients were divided into high SII and low
SII groups, and the differences in the clinical characteristics of the patients were compared between the two groups. Patients
were followed up after surgery. The recurrence curves of patients in high SII and low SII groups were plotted using the
Kaplan-Meier method. Multivariate Cox regression model was used to analyze the independent risk factors affecting tumor recurrence in NMIBC patients, and then these factors were included and a nomogram was constructed to predict the 1-year,
2-year and 3-year recurrence-free survival rate of NMIBC patients. The prediction accuracy and consistency of nomogram
were determined by the concordance index (C-index) and the calibration curve. ResultsThe areas under the curve (AUC)
of NLR, PLR and SII for predicting tumor recurrence in patients with NMIBC were 0.664, 0.656, and 0.729, respectively.
There was higher accuracy of SII in predicting tumor recurrence in NMIBC patients than that of NLR and PLR (Z=2.398,
2.454, respectively, both P<0.05). The optimal cut-off value of SII was 385, and 201 patients were divided into low SII group
(SII<385, n=130 ) and high SII group (SII≥385, n=71). Compared with the low SII group, the proportion of tumor volume ＞3
cm, the proportion of pathological T1 stage and tumor recurrence rate were higher in high SII group (all P＜0.05). The
median follow-up time of all patients was 62 (33-84) months after surgery, and 45 patients (22.4%) recurred during the
follow-up period. Multivariate Cox regression analysis showed that high SII (HR=2.829, 95%CI: 1.416-5.654), tumor T1
stage (HR=3.091, 95%CI: 1.660-5.757), tumor size >3 cm (HR=2.339, 95%CI: 1.152-4.751) and multiple tumors (HR=
2.083, 95%CI: 1.033-4.202) were independent risk factors for postoperative tumor recurrence (all P＜0.05). The C-index for
internal verification of nomogram was 0.768 (95%CI: 0.699-0.837). The calibration curves indicated good agreement
between the nomogram predictions and the actual observations. ConclusionPreoperative SII can be used as an indicator to
predict tumor recurrence in patients with NMIBC. The prediction accuracy of SII is higher than that of NLR and PLR. The
nomogram according to independent risk factors has high predictive value.

Key words: urinary bladder neoplasms, recurrence, nomograms, non-invasive bladder cancer, systemic immuneinflammatory index, transurethral resection of bladder tumor