Comparison of risk-calculator and MRI and consecutive pathways as upfront stratification for prostate biopsy

Abstract

Purpose: In biopsy naïve men suspected for prostate cancer (PCa), it is uncertain how a risk-calculator and bi-parametric (bp) MRI should be combined to decide on prostate biopsy, balancing cancer detection rates and diagnostic burden.

Methods: Prospective, single centre cohort study (August 2018-April 2019). All patients referred with serum PSA ≥ 3 ng/ml or abnormal digital rectal examination received bpMRI and risk for PCa was calculated using the ERSPC risk-calculator. Men with either PI-RADS ≥ 3 or calculator risk-score > 20% were recommended to undergo systematic biopsy (SB) and targeted biopsy (TB) of any visible lesion (reference pathway). Eight different derived diagnostic pathways were compared to the reference pathway regarding cancer detection, number of biopsies and bpMRIs performed.

Results: Of 496 patients; 233 (47%) had a risk-calculator score of > 20%; 201 (41%) had PI-RADS score ≥ 3. The reference pathway detected PCa in 32.1%, clinically significant (cs) PCa in 19.4%, with 41% avoided biopsies, but 0% avoided bpMRI. Stratification with only risk-calculator: 76% csPCa diagnosed, 53% avoided biopsies and 100% avoided bpMRI. Stratification with only bpMRI: 97% csPCa diagnosed, 59% avoided biopsies, but 0% avoided bpMRI. A pathway with risk-calculator first, followed only with bpMRI when high-risk: 81% csPCa diagnosed, 72% avoided biopsies and 53% avoided bpMRI.

Conclusion: Upfront bpMRI as a risk stratification tool outperforms risk-calculator in detecting significant disease. Applying the risk-calculator first to decide on performing an MRI, avoids 1 out of 2 MRIs, but up to 1 out of 5 significant cancers are missed.

Keywords: Prostate MRI; Prostate biopsy; Prostate cancer; Prostate cancer screening; Risk calculator; Risk-prediction tool.