Abstract
Background and objective
As most Prostate Imaging Reporting and Data System (PI-RADS) 5 lesions on MRI harbor Gleason grade (GG) group ≥2 disease on biopsy, optimal management of patients with imaging-biopsy discordance remains unclear. To estimate grade misclassification, we evaluated the incidence of Gleason upgrading among patients with GG1 disease in the setting of a PI-RADS 5 lesion.
Methods
We conducted a single-institution retrospective analysis to identify patients with GG1 prostate cancer on fusion biopsy with MRI demonstrating ≥1 PI-RADS 5 lesion. Primary study outcome was identification of ≥GG2 disease on subsequent active surveillance (AS) biopsy or radical prostatectomy (RP). We used multivariable models to examine factors associated with reclassification.
Results
We identified 110 patients with GG1 disease on initial biopsy and ≥1 PI-RADS 5 lesion. There were 104 patients (94.6%) initially managed with AS and 6 (5.5%) received treatment. Sixty-one patients (58.7%) on AS underwent additional biopsies. Of these, 43 (70.5%) patients had tumor upgrading, with 32 (74.4%) upgraded on first surveillance biopsy. Forty-four (40%) patients ultimately received treatment, including prostatectomy in 15 (13.6%) and radiation in 25 (22.7%). Two patients (1.8%) developed metastases. In multivariable models, genomic classifier score was associated with upgrading. Limitations include a lack of multi-institutional data and long-term outcomes data.
Conclusions
Most patients diagnosed with GG1 prostate cancer on MRI-Ultrasound fusion biopsy in the setting of a PI-RADS 5 lesion were found to have ≥GG2 disease on subsequent tissue sampling, suggesting substantial initial misclassification and reinforcing the need for confirmatory testing.