Performance of systematic, MRI-targeted biopsies alone or in combination for the prediction of unfavourable disease in MRI-positive low-risk prostate cancer patients eligible for active surveillance
To assess the upstaging/upgrading rates of low-risk prostate cancer (PCa) according to the biopsy scheme used (systematic (SB), targeted biopsies (TB), or both) in the setting of positive pre-biopsy MRI.
Patients and methods
We included 143 consecutive men fulfilling the Toronto University active surveillance (AS) criteria who underwent a pre-biopsy positive MRI, a combination of SB and software-based fusion TB, and a radical prostatectomy, in two expert centres. The primary endpoints were the pathological upgrading and upstaging rates. Overall unfavourable disease (OUD) was defined by any pT3-4 and/or pN1 and/or ≥ GG 3.
Using TB alone would have missed 21.7% of cancers including 16.7% of ≥ GG 3. The use of TB was significantly associated with a lower risk of ≥ Grade Group (GG) 3 disease (p < 0.006) in RP specimens. Combination of SB and TB lowered this risk by 39%, compared with TB alone. The biopsy scheme did not affect the upstaging rates which were substantial even in case of combination scheme (from 37 to 46%). OUD was detected in approximately 50% of cases. The presence of high grade on TB was the only independent predictive factor for both ≥ GG 2 (p = 0.015) and ≥ GG 3 (p = 0.023) in RP specimens.
High grade on TB biopsies represented the major predictor of upgrading. Combination of SB and TB better defined the sub-group of patients having the lowest risk of reclassification, compared with TB or SB alone. The risk of non-organ-confined disease remained high, and could not be accurately predicted by MRI or systematic/targeted biopsy features.
KeywordsProstate cancer Radical prostatectomy Active surveillance Low risk Biopsy Targeted biopsies, MRI Fusion biopsies
Protocol/project development: GP, BM and MR. Data collection or management: GP, J-BB, ML, CA, JA, RA, J-R G, GL, DP, AS, CT, MS, BM and MR. Data analysis: GP and MR. Manuscript writing/editing: GP, BM and MR.
Compliance with ethical standards
Conflicts of interest
The authors declares that they have no competing interest.
All procedures performed in studies involving human participants were in accordance with the ethical standards.
Informed consent was systematically obtained from each participant.