Objective To investigate the predictive value of preoperative fibrinogen (FIB) combined with systemic immune-inflammation index (SII) on biochemical recurrence (BCR) after radical prostatectomy for prostate cancer.

Methods A total of 110 prostate cancer patients were selected as study subjects, and the ROC curve was used to determine the optimal cut-off values of FIB and SII, establish the FIB-SII prognostic score, compare the correlation between the FIB-SII score and the clinical indexes of prostate cancer patients, and analyze the influencing factors of biochemical recurrence-free survival (BRFS) of prostate cancer patients.

Results The ROC curve analysis showed that the optimal cutoff values for FIB and SII were 3.08 g/L and 506.66, respectively. Based on these cutoff values, patients were divided into three groups: the FIB-SII 0 group (58 cases, defined as FIB ≤ 3.08 g/L or SII ≤ 506.66), the FIB-SII 1 group (24 cases, defined as FIB ＞ 3.08 g/L or SII ＞ 506.66), and the FIB-SII 2 group (28 cases, defined as FIB ＞ 3.08 g/L and SII ＞ 506.66). The 5-year biochemical recurrence-free survival rates for the FIB-SII 0, 1, and 2 groups were 74.1%, 57.0%, and 42.7%, respectively, with statistically significant differences among the groups (χ² = 14.51, P ＜ 0.01). Univariate Cox regression analysis showed that preoperative PSA, Gleason score, surgical margins, nerve invasion, pathological stage, FIB, SII and FIB-SII scores were influential factors affecting BRFS after radical prostate cancer patients. Multifactorial Cox regression analysis showed that Gleason score, surgical margins and FIB-SII score were independent influences on BRFS after radical prostate cancer patients.

Conclusion Preoperative FIB-SII score is an independent influence factor of BRFS after radical prostate cancer patients, and it has some value in predicting the prognosis of prostate cancer patients.