Should inclusion criteria for active surveillance for low-risk prostate cancer be more stringent? From an interim analysis of PRIAS-JAPAN.

PURPOSE: To define clinical and pathological factors predicting reclassification at the time of 1-year repeat biopsy (re-Bx) based on a Japanese cohort forming part of the Prostate Research International: Active Surveillance (PRIAS) study. PATIENTS AND METHODS: The inclusion criteria for the PRIAS study are as follows: clinical stage T1c/T2, PSA ≤ 10 ng/ml, PSA density (PSAD) < 0.2 ng/ml per milliliter, one or two positive biopsy cores, and Gleason score (GS) ≤ 6 at initial diagnostic biopsy. Baseline clinical characteristics and prostate-specific antigen doubling time (PSADT) at the time of re-Bx were analyzed via multivariate logistic regression with respect to reclassification and 'no cancer' status on the 1-year re-Bx. RESULTS: A total of 386 patients were enrolled in PRIAS-JAPAN by the end of 2013. Of these, 216 underwent re-Bx at 1 year. A total of 73 patients (33.8 %) were reclassified, whereas 74 (34.3 %) had no cancer. Older age, a higher PSAD, a higher positive core rate, and a shorter PSADT were significant predictors of reclassification. The positive core rate was the predictor common to reclassification, no cancer, and high GS, upon re-Bx. CONCLUSIONS: An interim analysis of a Japanese AS cohort participating in PRIAS revealed that the positive core rate was strongly associated with reclassification at the 1-year re-Bx. However, although amendment of the PRIAS inclusion criteria to incorporate a positive core might reduce any concern about underestimation, this would also reduce the number of patients undergoing AS.