Abstract: Abstract： Objective To evaluate the suitability of preoperative magnetic resonance imaging (MRI) positivity as a pre⁃ dictor of biochemical recurrence after radical prostatectomy (RP). Methods Data of 115 diagnosed prostate cancer patients with RP from 2006 to 2013 were collected retrospectively. According to MRI results, patients were divided into MRI positive group (n=87) and MRI negative group (n=28). The preoperative clinical data were compared between two groups. Biochemi⁃ cal recurrence was defined as increase or persistence of serum prostate specific antigen (PSA) levels>0.2 μg/L after surgery. Cox proportional hazard regression model was used to analyze the risk factors associated with biochemical recurrence. Re⁃ sults The survival time was shorter in MRI positive group than that of MRI negative group. The preoperative PSA level was higher in MRI positive group than that of MRI negative group (P < 0.05). There was no significant difference in the age of pa⁃ tients between two groups. In MRI positive group, the proportion of preoperative PSA>20 μg/L , the proportion of patients at clinical stage T3, the proportion of patients with pathological Gleason score≥8, the proportion of patients with seminal vesi⁃ cle invasion (SVI) and the proportion of patients with endocrine therapy were higher than those of negative group (P < 0.05). The univariate analysis showed that preoperative MRI positivity, PSA level, biopsy Gleason score, clinical stage, pathological Gleason score, SVI level and lymph node invasion (LNM) were associated with biochemical recurrence (P < 0.05)．However, the multivariate analysis showed that only preoperative MRI positivity, biopsy Gleason score and clinical stage were indepen⁃ dent prognostic factors (P < 0.05). Conclusion Preoperative MRI positivity can predict biochemical recurrence after RP successfully, and improve the prognosis of patients.

Key words: prostatic neoplasms, carcinoma, prostatectomy, recurrence, magnetic resonance imaging, survival analysis