Impact of immediate TRUS rebiopsy in a patient cohort considering active surveillance for favorable risk prostate cancer

Abstract

Introduction and objective: Active surveillance (AS) is an option for the management of favorable risk prostate cancer (CaP) in the PSA era. Published studies have reported variable inclusion criteria for cohort selection. Accurate assessment of individual patient risk in AS is dependent not only upon rigorous selection criteria, but also reliability of diagnosis at tissue biopsy. To date, the impact of immediate transrectal ultrasound (TRUS) rebiopsy in confirming candidates for AS has been incompletely defined.

Methods: From a total of over 567 men, 67 met criteria for AS (Gleason <7, PSA <10, PSAD <0.15, <3 cores with <50% involvement of any 1 core). Fifty-two men agreed to a 12-core TRUS rebiopsy within 6 months of first diagnosis performed in clinic. Statistical analysis was performed using Wilcoxon signed rank test and logistic regression to determine predictors of rebiopsy characteristics, histopathologic outcomes, and impact on treatment choice.

Results: Mean cohort age was 63.9 years (range 56-72 years), PSA 5.9 ng/ml (4.1-10), and PSA density 0.12 ng/ml/cc at initial biopsy. Tumor involved 1.1 cores and 3.2% (range 1%-5%) of the total tissue. Average time to rebiopsy was 2.7 months. Notably, 29 of 52 men (56%) demonstrated no evidence of CaP on repeat biopsy; 14 of 23 men with a positive repeat biopsy showed either an increase in cancer volume (2.8% mean increase) and 9 (18%) were upgraded to Gleason pattern 3+4 = 7. Rebiopsy demonstrated 9 (17%) patients exceeded AS criteria. Nine patients chose curative surgical intervention (radical prostatectomy) based on increased cancer volume or grade (4) or an elective desire for treatment (5). All had organ confined disease with negative margins on final pathologic analysis. Statistical review revealed that initial Gleason score, PSA density, and number of positive cores at first biopsy were not predictive of men with higher volume/grade on re-biopsy.

Conclusions: Immediate TRUS repeat biopsy after diagnosis frequently fails to redemonstrate prostate cancer confirming the favorable-risk nature of disease burden in this group being considered for AS. A subset of patients are upgraded (17%) leading to reconsideration of AS. We conclude this clinic-based approach provides valuable additional information to discriminate appropriate AS candidates.

Keywords: Active surveillance; Prostate cancer; TRUS biopsy.