Routine prostate biopsies not needed after cryotherapy if surveillance MRI is normal.

OBJECTIVES

To compare the clinically significant prostate cancer detection rate (csPCaDR) and pathological characteristics of magnetic resonance imaging (MRI) visible (MRIv) and MRI invisible (MRIi) cancers among men undergoing surveillance after ablative focal therapy (AFT) for intermediate-risk PCa.

PATIENTS AND

METHODS

A total of 305 five men enrolled in an Institutional Review Board-approved primary partial gland cryoablation (PPGCA) outcomes registry meeting the following inclusion criteria: an MRI region of interest (ROI) Prostate Imaging-Reporting and Data System 2-5 concordant with unilateral intermediate-risk disease (Gleason Grade Group [GGG] 2 or 3 disease), no gross extraprostatic extension on MRI, no GGG ≥2 contralateral to the ROI, and at least 6 months of follow-up. Protocol MRI was performed at 6, 24, 42 and 60 months. Biopsy indications evolved over time. Any Gleason pattern 4 (GP4) represented a clinically significant PCa recurrence (csPCaR). Pathological disease characteristics, csPCaDR, and salvage treatments were compared for MRIv and MRIi disease. Baseline and post-treatment characteristics were compared between MRIv and MRIi csPCaR. Ordinal and binary measures were compared with Mann-Whitney rank-sum test. Categorical testing for differences was performed with chi-square testing.

RESULTS

Of 665 post-treatment MRIs, 87 (13.1%) and 578 (86.9%) were positive (+ve) and negative (-ve) for csPCaR, respectively. Biopsies were taken in 62 of the 87 +ve MRIs and 179 of the 578 -ve MRIs, with a csPCaDR of 43.5% and 10.6% for +ve and -ve MRI, respectively. Of the 46 csPCaRs, 28 (61%) and 18 (39%) were associated with +ve and -ve MRI, respectively. The median linear length of GP4 for MRIv and MRIi csPCaR was 2.6 and 0.6 mm, respectively (P = 0.08). Four (14%) and eight (44%) MRIv and MRIi csPCaRs were managed with continued active surveillance (P = 0.03).

CONCLUSION

The cost and morbidity of surveillance following PPGCA can be safely reduced by avoiding biopsy in most cases with -ve MRI.