Transition zone prostate cancer is associated with better clinical outcomes than peripheral zone cancer

OBJECTIVES: To determine the biological significance of zonal origins in prostate cancer. PATIENTS AND METHODS: Altogether, 270 consecutive radical prostatectomy cases from 2009 to 2012 were adopted. Cases were divided into those having transition zone (TZ) cancer or peripheral zone (PZ) cancer. Cases with indeterminate tumor location and central zone cancers were excluded from the analyses. Prognosis and clinicopathological features were compared between the two tumor locations. Biochemical recurrence (BCR) and clinical progression (CP) were adopted as prognostic outcome measures. Immunohistochemical features of the v‐ets avian erythroblastosis virus E26 oncogene homolog (ERG)/serine peptidase inhibitor, Kazal‐type 1 (SPINK1) status, and loss of phosphatase and tensin homolog (PTEN‐loss), as well as conventional preoperative and postoperative characteristics, were analyzed. RESULTS: This cohort comprised 93 cases of TZ cancer and 160 cases of PZ cancer. TZ cancer cases showed significantly higher BCR and CP‐free survival rate than PZ cancer cases. Notably, no TZ cancer cases developed CP during the 7.8 years of median follow‐up time. Tumor location was an independent predictive factor for BCR in the multivariate analysis. Additionally, TZ cancer cases showed a significantly lower prevalence of ERG‐overexpression and PTEN‐loss than PZ cancer cases (3.2% vs 20.1% and 2.2% vs 18.2%, respectively). CONCLUSION: TZ cancer cases showed a better prognosis and different immunohistochemical features. Conservative treatment strategies could be considered for TZ cancer cases.