Early oncological control following partial gland cryo-ablation: a prospective experience specifying reflex MRI guided biopsy of the ablation zone.

Background: Several consensus statements recommend serial serum prostate-specific antigen (PSA), multi parametric magnetic resonance imaging (mpMRI), and prostate biopsy following partial gland ablation. We determined the rate of persistent in-field disease following primary partial gland cryo-ablation and whether PSA or mpMRI are reliable predictors of in-field disease persistence.

Methods: Between March 2017 and July 2019, subjects meeting eligibility criteria for partial gland cryoablation were enrolled into an IRB approved outcomes registry. PSA, mpMRI, and prostate biopsy (four cores targeting the ablation zone + six ipsilateral systematic cores) were performed per protocol 6 months following intervention. Binary logistic regression was employed to calculate odds ratio (OR) of PSA decrease, and suspicious mpMRI effect on cancer persistence. The performance of mpMRI for predicting in-field persistence of PCa was evaluated by area under the receiver operation characteristics curve (AUC).

Results: Of the 83 eligible men undergoing partial gland cryoablation, 70 (84.3%) underwent 6-month protocol prostate biopsy. Five (7.1%) biopsies exhibited any in-field disease persistence. Only one (1.4%) of these cancers was Gleason grade > 1. Neither PSA decrease or suspicious mpMRI reliably predicted cancer persistence, with OR of 1.6 (0.25-8.6) and 1.5 (0.02-1.3), respectively. AUC of mpMRI for predicting in-field disease persistence was 0.554.

Conclusions: In this cohort of patients undergoing partial gland cryo-ablation, the incidence of persistent disease was low. PSA and mpMRI were not reliable predictors of in-field disease persistence. Based on these data, consideration may be given to deferring early follow-up biopsy in appropriate patients.