Preoperative C-reactive protein to albumin ratio as a novel prognostic biomarker for the oncological outcomes of radical nephroureterectomy.

PURPOSE: This study aimed to evaluate the prognostic impact of the preoperative C-reactive protein to albumin ratio (CAR) on progression-free survival (PFS) and cancer-specific survival (CSS) in patients with upper urinary tract urothelial carcinoma (UTUC) undergoing radical nephroureterectomy (RNU).

METHODS: A retrospective analysis was conducted using data from a single-center nephroureterectomy registry between January 2011 and December 2017. Participants were categorized into high and low CAR groups based on the optimal CAR cut-off value determined using the Youden index. The primary endpoint was PFS, the time from RNU to metastasis or disease recurrence. The secondary endpoint was CSS, the time from RNU to UTUC-related death. Median PFS and CSS were compared between the high and low CAR groups using Kaplan-Meier analysis and log-rank test. Multivariable Cox proportional hazard regression analysis was performed to assess the prognostic significance of CAR, adjusting for known prognostic factors.

RESULTS: We included 491 patients with UTUC in the analysis. The optimal CAR cut-off value was determined to be 0.036, which resulted in classifying 49.3% (242/491) of patients into the high CAR group. The high CAR group had older patients (69.8 vs. 67.4, p-value = 0.01), advanced T and N stages (p-value<0.001), high-grade tumor (p-value = 0.03), and a higher incidence of preoperative hydronephrosis (p-value < 0.01) than the low CAR group. The high CAR group demonstrated significantly inferior median PFS (78.3 vs. 100.3 months, p-value < 0.01) and CSS (73.2 vs. 96.1 months, p-value < 0.01) than the low CAR group. Moreover, high CAR independently increased the risk of disease progression (hazard ratio [HR]: 1.80, 95% confidence interval [CI]: 1.23-2.64, p < 0.01) and UTUC-related mortality (HR: 1.79, 95% CI: 1.15, p < 0.01).

CONCLUSION: Pre-operative CAR is independently associated with poor PFS and CSS in patients with UTUC undergoing RNU. Moreover, CAR may be an independent UTUC prognostic factor, offering a cost-effective and minimally invasive marker. However, further validation through large-scale, multi-center studies is necessary to confirm these findings and determine the optimal CAR cut-off value.