Serial biopsy is a mainstay for patients on active surveillance (AS) for prostate cancer. mpMRI targeting has become a standard. It is unclear whether targeted biopsy alone reliably identifies the dominant lesion, thereby obviating the need for systematic sampling.
Participants enrolled in AS with early-stage prostate cancer (PSA < 20, cT1-2, GG1-2) and underwent 2+ systematic biopsy sessions with or without MR-targeted sampling. Findings for dominant Gleason Grade (GG) and tumor localization were assessed.
Among 821 men who underwent MR fusion biopsies, 82% were diagnosed with GG1 and 18% with GG2. Sixty-two percent had their first MR fusion biopsy as diagnostic or confirmatory. Across all fusion biopsies, MRI-targeted detection of GG and/or tumor location overlapped with systematic sampling for 95% of cases. For 5% of cases, systematic biopsy was unique in detecting GG and location outside the target. Most unique lesions detected outside the target had marginally aggressive features: 73% GG2 of low volume and favorable histologic subtypes.
In men with MR-fusion biopsies, targeting alone identified the dominant GG and location most of the time (95%); 25% of dominant lesions were contiguous to the target suggesting that better sampling of the target improves detection. The remaining 5% of men had higher grade, low volume disease outside the targeted lesion of which only 2% had aggressive risk features. MR fusion targeting, without systematic sampling, may be sufficient to monitor men on AS. Few high risk cancers are missed, all of limited volume and favorable histology.
The Journal of urology. 2024 Oct 09 [Epub ahead of print]
Mary O Fakunle, Janet E Cowan, Samuel L Washington, Katsuto Shinohara, Hao G Nguyen, Peter R Carroll
Department of Urology and Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, California.