Active surveillance (AS) has gained acceptance as an alternative to definitive therapy for many men with prostate cancer (PCa). Confirmatory biopsies to assess the appropriateness of AS are routinely performed and negative biopsies are regarded as a favorable prognostic indicator. Our study sought to determine the prognostic implications of negative multi-parametric magnetic resonance imaging (mpMRI)-transrectal ultrasound (TRUS) guided fusion biopsy (FB) consisting of extended sextant, systematic biopsy (SB) plus mpMRI-guided targeted biopsy of suspicious MRI lesions.

All patients referred with Gleason Grade Group (GG) 1 or 2 PCa based on an outside SB underwent confirmatory FB. Patients continuing AS after positive FB (FB(pos)) or negative FB (FB(neg)) were followed. Baseline characteristics of the FB(neg) and positive FB FB(pos) patients were compared. Cox-regression analysis was used to determine the prognostic significance of a FB(neg). Kaplan-Meier survival curves were used to estimate GG progression over time.

542 patients were referred with GG 1 (466) or GG 2 (76) PCa of whom 111 (20.5%) were FB(neg). A total of 60 FB(neg) and 122 FB(pos) patients were followed on AS with median times to GG progression of 74.3 and 44.6 months, p<0.01, respectively. A negative FB was associated with a reduction in the risk of GG progression (HR 0.41 95% CI 0.22-0.77, p<0.01).

A negative confirmatory FB confers a favorable prognosis for GG progression. These results can be used when counseling patients about the risk of progression and planning future follow-up and biopsies for patients on AS.