Abstract: PD61-05
Sources of Funding: Joseph and Diane Steinberg Charitable Trust

Introduction

While the value of MRI-US Fusion-targeted biopsy (MRF-TB) in the identification of occult, clinically significant prostate cancer (csPCa), has been well described, the accuracy of targeting using available fusion platforms is not as clear. As the need for repeat biopsy among men with negative or low risk MRF-TB remains to be defined, we evaluated the outcomes of repeat MRF-TB among men with initially negative or low risk MRF-TB.

Methods

Between 6/2012 and 9/2016, 1,584 consecutive men undergoing pre-biopsy prostate MRI followed by MRF-TB and systematic biopsy (SB) were enrolled in prospective date registry. 195 men underwent repeat MRI and MRF-TB for continued suspicion of csPCa. 76 men were excluded from analysis due to outside facility or 1.5T MRI, hip implant or interval focal therapy. Upgrade was defined as an increase in Gleason score (GS) from 3+3 to ≥3+4 or from 3+4 to ≥4+3 among men with PCa noted on first MRF-TB, or any cancer among men with no cancer on first MRF-TB. Biopsy outcomes were stratified per MRI findings and progression.

Results

119 men (mean age 65.9±7.7 years, mean PSA 5.8±4.5 ng/mL) underwent repeat MRF-TB. The median interval between initial and repeat biopsy was 17.1±8.9 months. On repeat biopsy, 50% (59) had concordant GS, 17% (20) were downgraded, and 34% (40) were upgraded. Of the 40 upgrades, 42% (17) were due to an increase in GS and 58% (23) were due to newly detected PCa, as illustrated in Table 1._x000D_ _x000D_ PI-RADS score was predictive of the likelihood of upgrade on repeat MRF-TB (Table 2). 53% of men with PI-RADS 4 and 5 demonstrated upgrade on repeat biopsy compared to 26% of men with PI-RADS 3. 82% (9/11) of upgrades in men with PI-RADS 1 and 2 were due to newly detected GS 6 disease.

Conclusions

53% of men with PI-RADS 4 and 5 lesions were upgraded on repeat MRF-TB, suggesting a need for repeat sampling among men with low risk or negative MRF-TB and persistent PI-RADS 4 and 5 regions noted on follow-up MRI. Among men with PI-RADS 1 or 2 on repeat imaging, continued observation may be reasonable given the low likelihood (5%) of csPCa on repeat MRF-TB.

Funding

Joseph and Diane Steinberg Charitable Trust