Frozen section analysis assisted MRI targeted prostate biopsy - results of the randomized clinical FAST trial

Multiparametric magnetic resonance imaging (mpMRI) targeted prostate biopsy is still commonly combined with systematic biopsy, resulting in a high number of extracted biopsy cores. This study evaluated whether a frozen section analysis (FSA) guided biopsy strategy enabling immediate assessment of targeted biopsy and omitting systematic biopsy in case of clinically significant prostate cancer (csPCa) is non-inferior to standard combined biopsy while substantially reducing the number of biopsy cores.

In this prospective randomized trial, men with PI-RADS ≥ 4 lesions were randomized to standard combined biopsy (Arm A) or FSA guided primarily MRI-targeted biopsy (Arm B). In Arm B, three targeted cores were obtained, with two immediately analyzed by FSA. Additional systematic biopsy was performed only if FSA was negative or inconclusive. The primary endpoint was detection of csPCa (ISUP grade group ≥2). A non-inferiority margin of -10 %age points was prespecified.

A total of 160 patients were randomized (Arm A: 80, Arm B: 80). csPCa detection rates were 93% in Arm A and 97% in Arm B, yielding a risk difference of 5.0% (95% CI -5.2-14.7), meeting non-inferiority criteria. The median number of biopsy cores was reduced from 15 to 3 in Arm B (p < 0.001). Pain, discomfort, macrohematuria, and hematospermia were significantly lower in the experimental arm (all p < 0.05).

FSA guided prostate biopsy enabling immediate assessment of targeted biopsy cores is safe, minimally invasive, and non-inferior regarding the detection of csPCa to standard biopsy in men with suspicious mpMRI lesions. This approach substantially reduces biopsy cores and patient burden by omitting systematic biopsy in case of positive FSA while maintaining oncological safety.