Positive association between preoperative lymphocyte-to-monocyte ratio and risk of the status of positive surgical margins by prostate cancer: results in 497 consecutive patients treated only by radical prostatectomy

Background Positive surgical margins (PSM) is one of the most important factors affecting the prognosis of prostate cancer (PCa) patients after radical prostatectomy (RP). Although some studies have found the preoperative systematic inflammation-based scores the neutrophil-to-lymphocyte ratio (NLR), the platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR) can predict the incidence and prognosis of PCa, few studies have explored the predictive value of preoperative systematic inflammation-based scores on the PSMs for PCa patients after RP. Methods From June 2014 to September 2020 a total of 497 patients underwent RP at our institution. Blood samples from all patients were collected within one week before surgery. Preoperative clinical characteristics including age, body mass index (BMI), prostate-specific antigen (PSA), and biopsy Gleason sum (BGS) were assessed. Postoperatively pathological specimens were assessed for pathological Gleason sum (PGS), pathological stage, and margin status. Results In the multivariable analysis including preoperative variables, PSA and LMR were the independent predictive factors for PSM (OR: 2.817; 95% CI, 1.836-4.320, P<0.001; OR: 1.124; 95% CI, 1.018-1.240, P=0.021. Considering pre-, intra-, and postoperative variables, BGS, perineural invasion, seminal vesicle invasion (SVI), pathologic Gleason sum (PGS) combined, were associated with increased risk of PSM in the univariable analysis (P<0.001 for all variables). However, in the multivariable analysis, perineural invasion (OR: 2.672; 95% CI, 1.649-4.330; P<0.001), PGS (OR: 2.52; 95% CI, 1.556-4.082; P<0.001) were independent predictive factors for the incidence of PSM. Finally, LMR was shown to be an independent predictive factor (OR: 0.881; 95% CI, 0.779-0.996; P=0.043) for apical PSMs, with increasing LMR predicting the lower incidence of apex location. And we also found that LMR was an independent factor that predicts multifocal positive margins (OR: 1.179; 95% CI, 1.023-1.358; P=0.023). Conclusions Preoperative LMR could be used as an independent predictor to predict the incidence of PSMs after RP. And Considering pre-, intra-, and postoperative variables, we also found that preoperative LMR could predict the occurrence of apical and multifocal PSMs.