Presentation Authors: Alice Yu*, Timothy Baloda, Eduoard Nicaise, Andrew Gusev, Mukesh Harisinghani, Amirkasra Mojtahed, Douglas Dahl, Matthew Wszolek, Anthony Zietman, Adam S. Feldman, Boston, MA
Introduction: Multiparametric MRI (mpMRI) has led to improved detection of clinically significant prostate cancer and is now increasingly used in active surveillance (AS) patients. However, most AS cohorts in the literature were described prior to widespread use of mpMRI. Our investigation compares outcomes in AS in the pre- and post-MRI era at our institution.
Methods: We used an institutional database of 1295 men who started AS between September 1996 to December 2016. The cohort was divided into pre- and post-MRI era with the cutoff in January 2014, when mpMRI was routinely incorporated into our AS protocol. Clinical outcomes were compared using Wilcoxon rank sum and Chi-square tests. Treatment-free survival was analyzed using Kaplan-Meier plots.
Results: All patients (251) in the post-MRI era had at least one mpMRI performed compared to 5.3% (55/1044) of those enrolled earlier. There was no significant difference in baseline PSA (p=0.36) or Gleason Score (GS) (p=0.395). Mean time to follow-up in the post-MRI era was 3.0Â±0.9 years compared to 8.0Â±5.1 years in the pre-MRI era. At 2 years, 21.8% of patients in the post-MRI era were treated as compared 15.7% in the pre-MRI era. By Kaplan-Meier, patients in the post-MRI group had a shorter time to treatment (1.5 vs 2.8 years, P < 0.001) (Figure 1). Among those treated, 288 underwent radical prostatectomy (RP). On surgical pathology, 4.2% of patients in the pre-MRI group had GS 8 or 9 disease, 59.0% had GS 7, and 36.8% had GS 6 disease. This is compared to 0%, 75.0% and 25.0%, respectively, in the post-MRI group. There was no difference in pathologic T stage, N stage and positive margin rates.
Conclusions: With widespread utilization of mpMRI, patients on AS are treated earlier. However, further follow up will be needed to see if this earlier identification and treatment of clinically significant disease ultimately results in a plateau in long-term treatment free survival.