Preoperative models incorporating the systemic immune-inflammation index for predicting prognosis and muscle invasion in patients with non-metastatic upper tract urothelial carcinoma.

Objective: To develop preoperative models as a guide to indications for neoadjuvant chemotherapy (NAC) and regional lymph node dissection (LND) before and at radical nephroureterectomy (RNU), respectively, in patients with non-metastatic upper tract urothelial carcinoma (UTUC) by incorporating the systemic immune-inflammation index (SII).

Methods: This retrospective study enrolled 103 consecutive patients with UTUC undergoing RNU. The SII was calculated as neutrophils × platelets / lymphocytes. Multivariable Cox proportional hazard model was used to develop preoperative models for cancer-specific survival (CSS) and overall survival (OS). A model for predicting muscle invasion was developed using logistic regression analysis. Harrell's concordance-index (c-index) or the area under the receiver operating characteristic curve (AUC) was used to evaluate the accuracy of the models.

Results: During follow-up (median: 41 months), 26 and three patients died of UTUC and other causes, respectively. Performance status > 0, clinical tumor (cT) stage ≥ 3, and SII > 520 were independent adverse prognosticators for CSS, and one point was assigned to each prognosticator. Risk score models comprising the sum of the points stratified patients into three risk groups (0, 1, and 2-3; P < 0.001 for CSS and OS) with respective c-indices of 0.843 and 0.820. SII > 677 and ≥ cT3 were independently associated with muscle invasion. A model based on these variables predicted muscle invasion with AUC of 0.804.

Conclusion: Preoperative SII is significantly associated with worse survival outcomes and muscle invasion in patients with non-metastatic UTUC. Our preoperative predictive models may serve as a guide to indications for NAC and LND.