Introduction:

We retrospectively reviewed the follow-up findings of patients who had undergone prostate biopsy for their PIRADS 4 or 5 multiparametric MRI(mpMRI) findings (all PIRADS versions) and had a negative histology.

Methods:

There were 162 biopsy naive patients between 2012-2021 fulfilling these criteria. 25% of the patients had suspicious DRE findings. All MRI ‘s were evaluated by two very experienced uroradiologists. 104 patients had either cognitive or software fusion MR targeted biopsies with 4+8/10 cores. The remaining 58 patients had in bore biopsies with 4-5 cores.

Results:

Mean patient age and PSA were 62.4±8.7 and 7.2±2.9, respectively at the initial work-up. In a mean follow-up period of 42±22months, 44 (27.1%) patients were lost to follow-up. Details of the follow-up were at the attending physician ‘s discretion (reevaluation of DRE/initial mpMRI etc). Of the remaining 118 patients, 48 (40%)  had continuously regressive PSA findings and 70 (60%) had  persistently high PSA. Of these 70 patients, 48 (69%) had repeat mpMRI within 6-24 months which showed in  30 patients  (63%)  regressive findings  (PIRADS 1-3) and in  18 (38%) PIRADS 4-5 index lesion persistence . The latter group was recommended to have a re-biopsy. 13 of these 18 patients underwent MRI targeted re-biopsy. Prostate cancer was diagnosed in 5 (38%) patients, of those 3 (23%) were clinically significant (>GG1).

Conclusion:

Patients should be warned against the relative  relaxing effect of  a negative biopsy in the face of a PIRADS 4-5 index lesion. While PSA decrease was observed in most patients during the follow-up, persistent MRI findings were present in nearly half of the patients with persistently high PSA. A re-biopsy is warranted in those patients which showed significant prostate cancer in a quarter of the patients. 

Funding: N/A