San Diego, CA USA (UroToday.com) In this session, Dr. Ristau presented his work from the Fox Chase Cancer Center on defining deliverables of mutiparametric magnetic resonance imaging (mpMRI)/ultrasound (US) fusion-guided targeted prostate biopsy.
The authors asked two questions: (1) What does targeted biopsy (TB) add over traditional transrectal ultrasound guided biopsy (TRUSB) and (2) How close are we to relying solely on the TB (i.e. removing concomitant TRUSB altogether)?
To assess this, Dr. Ristau and his colleagues developed two metrics: Actionable Intelligence Metric (AIM) and Reduction Metric (RM). These metrics were then applied to 3 distinct patient populations: (1) biopsy naïve, (2) elevated PSA with prior negative biopsy, and (3) patients on active surveillance (AS). The AIM was defined as detection of clinically significant (Gleason 3+4=7 or higher) prostate cancer on TB that was not detected on the concomitant TRUSB. This ranged from 20-47% depending on the cohort and suggested that TB added the most information in the elevated with prior negative biopsy cohort.
The reduction metric was defined as detection of clinically significant prostate cancer on TRUSB that was not detected on the concomitant TB. The resulting percentage represents the number of patients who would have had no upgrading if the TRUSB had been eliminated from the protocol. Depending on the setting, RM ranged from 72-89%. Eliminating TRUSB would result in missing the most clinically significant cancers in the AS cohort.
Both the AS and RM compared favorably with literature that contained enough information in publications to perform the calculations.
Taken together, the authors concluded that targeted biospy holds potential for improvement in prostate cancer diagnosis over TRUS-B. Two metrics – Actionable Intelligence Metric (AIM) and Reduction Metric (RM) – are introduced to help quantify, communicate, and compare deliverables of MRI-guided fusion targeted biopsy technology. Finally, they noted that further validation of these metrics in larger cohorts is needed.
Presented By: Benjamin T. Ristau, MD