Prognostic value of preoperative fibrinogen in metastatic clear cell renal cell carcinoma patients undergoing cytoreductive nephrectomy: A propensity score-matched study.

563 Background: The measurement of serum fibrinogen (FIB) levels is often overlooked in metastatic clear cell renal cell carcinoma (mccRCC). This study aims to investigate the prognostic value of preoperative serum FIB levels in mccRCC patients undergoing cytoreductive nephrectomy (CN) followed by systemic therapy. Methods: This retrospective study analyzed 209 mccRCC patients who underwent CN from 2010 to 2022. The optimal cutoff value of preoperative serum FIB levels was determined via receiver operating characteristic (ROC) curve. Survival outcomes were evaluated by the Kaplan-Meier method and Cox proportional hazards models. The predictive ability was evaluated by ROC curve. Propensity Score Matching (PSM) was performed to equate demographic and clinical characteristics. Results: An optimal cutoff value of 4.39 g/L for the FIB levels was determined and patients were categorized into high and low FIB groups. With a median follow-up time of 61.1 months, patients in the low FIB group exhibited significantly higher median OS compared with the high FIB group (53.1 vs 27.9 months, p < 0.001). The ROC curve demonstrated that the serum FIB predicted a 36-month overall survival with an AUC of 0.652, while the AUC for the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) risk category was 0.558. After PSM matching, high FIB levels remained significantly associated with poorer OS (24.0 vs 50.2 months; p = 0.019). Conclusions: Serum FIB level is a significant prognostic factor for mccRCC patients undergoing CN followed by systemic therapy. This finding underscores the potential of FIB as a biomarker that could be integrated into the prognostic model for preoperative risk stratification and management strategies.