The role of PSA kinetics in men with a negative MRI-targeted prostate biopsy.

Objective: To evaluate rebiopsy rates and clinicopathologic outcomes in patients after a negative MRI-guided biopsy to better inform the management of these patients.

Methods: Patients were included with a clinical suspicion of prostate cancer (PCa) referred for fusion biopsy for a PI-RADS v2.1 lesion ≥ 3 on multiparametric MRI and a negative MRI fusion biopsy. Biopsies included targeted and systematic cores. Patients with a prior cancer diagnosis were excluded. Both baseline and follow-up clinicopathological data, and long-term PSA values were examined in these patients. Statistical analyses included Wilcoxon rank-sum test and one-way tests.

Results: Of 685 total patients, 188 (27%) had a negative fusion biopsy. Of these 88 (47%), 74 (39%), and 26 (14%) had PI-RADS 3, 4, 5 lesions, respectively. Complete follow-up was available for 182/188 patients (97%), with a median of 24 months (interquartile range: 12-38). Post-biopsy PSA levels decreased the first and the second year (-0.24; and -0.84 ng/ml/yrs respectively). In follow-up, 44 patients had an MRI (24%) and 20 had a biopsy (10%). A positive PSA velocity was the only predictive variable for repeat MRI in univariate analysis. On repeat MRI, 9 (27%) patients had disappearance of the initial lesion, 21 (48%) had a lower PIRADS score and 14 (32%) higher. Only 12/182 (6.6%) were found to have PCa during follow-up, of those 7 (3.8%) were clinically significant.

Conclusion: For patients with nonmalignant biopsy findings after an initial mpMRI showing a suspicious PI-RADS lesion, the majority of patients will have their PSAs return to baseline over time. To support this, repeat MRI frequently demonstrated a disappearance or downgrading of PIRADS lesions. These data support monitoring patients with this clinical scenario.