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 study compares AS outcomes in the MRI and pre-MRI era at our institution.  

Methods:

We used an institutional database of 1291 men enrolled in AS between September 1996 and December 2016. The cohort was divided into pre- and post-MRI era with the cut-off in July 2014, when mpMRI-US fusion biopsy was routinely incorporated into our AS protocol. Treatment-free survival was compared using the log-rank test and multivariable Cox regression. 

Results:

In total, 276 were from the MRI era and 1015 were from the pre-MRI era. Freedom from treatment at 2 and 5 years were 82% vs 90% and 63% vs 77% in the MRI and pre-MRI eras respectively. Men in the MRI era were more likely to undergo treatment even after controlling for baseline characteristics (P=0.003). Median time between diagnosis and treatment was 2.5 years (interquartile range, IQR 1.7-3.4) in the MRI era versus 5.9 years (IQR 2.8-8.9) in the pre-MRI era.

Conclusion:

In the MRI-era, men on active surveillance experienced earlier disease reclassification. 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. 

Funding: N/A