Concordance Between MRI Findings and Targeted Biopsy for Local Recurrence Following Radical Prostatectomy

To characterize biopsy outcomes for lesions suspicious for prostate bed recurrence detected on magnetic resonance imaging (MRI) after radical prostatectomy (RP) and therefore improve understanding of the correlation between MRI suspicion for recurrence and biopsy-confirmed viable cancer.

We identified patients with biochemical recurrence (BCR) after RP who underwent MRI-targeted biopsy of a suspected prostate bed lesion from 2013 to 2019. A 5-point index score was used by a genitourinary radiologist to grade radiographic suspicion for recurrent prostate cancer. Targeted biopsy of the MRI lesion served as the reference standard. We then evaluated for associations between clinicopathologic factors and biopsy outcome.

Targeted biopsy was positive in 52 of 94 patients overall (55%). Higher index of suspicion on MRI was associated with increased probability of biopsy-confirmed recurrent cancer in the prostate bed (90% for score of 5; 36% for scores 1-2, P = .003). Receipt of androgen deprivation therapy after RP and before recurrence biopsy was significantly associated with positive biopsy (29% vs 9.5%; P = .022). Adverse pathology at RP and time to BCR were not associated with biopsy outcomes.

MRI is an important tool for detecting prostate bed recurrences; lesions with a high index of suspicion on MRI are likely to represent viable cancer on biopsy. Suspected local recurrences on MRI should be accompanied by confirmatory biopsy in patients who are eligible for salvage radiotherapy to a recurrent nodule in the prostate bed for possible dose escalation.