Lymphocyte-to-monocyte ratio is a predictor of clinically significant prostate cancer at prostate biopsy

Inflammation plays critical roles at different stages of carcinogenesis and cancer progression. Several previous studies showed conflicting results for the predictive role of systemic inflammation markers in the detection of clinically significant prostate cancers (CSPCs). We aimed to determine the predictive roles of lymphocyte-to-monocyte (LMR) and eosinophil-to-lymphocyte ratios (ELR) in the detection of CSPC at standard 12-core transrectal ultrasound-guided prostate biopsy (12-core-TRUS-Bx) using our large-cohort database.

Clinical and pathological data of a total of 1740 men, who underwent initial standard 12-core TRUS-Bx, were analyzed. LMR and ELR were calculated from the prebiopsy complete blood count. Definitions of CSPC, LMR, and ELR were "Gleason grade group ≥2," "the lymphocyte counts/the monocyte counts," and "the eosinophil counts/the lymphocyte counts," respectively.

Median (interquartile range) of serum prostate-specific antigen (PSA) level and prostatic volume before TRUS-Bx were 7.59 (5.02-13.12) ng/ml and 38.2 (29.0-52.9) ml, respectively. Benign prostatic lesions, clinically insignificant prostate cancers (CIPCs), and CSPCs were detected in 1179 (67.8%), 180 (10.3%), and 381 (21.9%) patients, respectively. The patients with CSPCs had older age, a higher prevalence of diabetes mellitus or hypertension, a higher rate of digital rectal examination abnormality, higher serum PSA level, lower serum testosterone level, and lower LMR than those with benign lesions or CIPCs. However, there was no difference in ELR among the three (benign lesions, CIPCs and CSPCs). In all the patients, multivariate regression analysis showed that lower LMR was an independent predictor of CSPCs compared with ELR. In the subset of men with prostate volume ≥39.3 ml, lower LMR was an independent predictor of CSPCs compared with ELR. In the subset of men with prostate volume <39.3 ml, men with lower LMR showed the tendency of having a higher probability of CSPCs without any statistical significance on the contrary to ELR.

Our data indicate that LMR can play an independent predictive role in the detection of CSPCs at initial 12-core-TRUS-Bx compared with ELR. The predictive role of the LMR appears to be significant for men with larger prostate volume rather than those with smaller prostate volume.