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Updated: Oct 15, 2025
Use of MRI-ultrasound Fusion to Achieve Targeted Prostate Biopsy
Published on: April 9, 2019
Repeat MRI during active surveillance: natural history of prostatic lesions and upgrading rates
Stefano Luzzago1,2, Mattia Luca Piccinelli1,3, Francesco A Mistretta1
1Department of Urology, IEO European Institute of Oncology, IRCCS, Milan, Italy.
Objectives:
To assess upgrading rates in patients on active surveillance (AS) for prostate cancer (PCa) after serial multiparametric magnetic resonance imaging (mpMRI).
Methods:
We conducted a retrospective analysis of 558 patients. Five different criteria for mpMRI progression were used: 1) a Prostate Imaging Reporting and Data System (PI-RADS) score increase; 2) a lesion size increase; 3) an extraprostatic extension score increase; 4) overall mpMRI progression; and 5) the number of criteria met for mpMRI progression (0 vs 1 vs 2-3). In addition, two definitions of PCa upgrading were evaluated: 1) International Society of Urological Pathology Grade Group (ISUP GG) ≥2 with >10% of pattern 4 and 2) ISUP GG ≥ 3. Estimated annual percent changes methodology was used to show the temporal trends of mpMRI progression criteria. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of mpMRI progression criteria were also analysed. Multivariable logistic regression models tested PCa upgrading rates.
Results:
Lower rates over time for all mpMRI progression criteria were observed. The NPV of serial mpMRI scans ranged from 90.5% to 93.5% (ISUP GG≥2 with >10% of pattern 4 PCa upgrading) and from 98% to 99% (ISUP GG≥3 PCa upgrading), depending on the criteria used for mpMRI progression. A prostate-specific antigen density (PSAD) threshold of 0.15 ng/mL/mL was used to substratify those patients who would be able to skip a prostate biopsy. In multivariable logistic regression models assessing PCa upgrading rates, all five mpMRI progression criteria achieved independent predictor status.
Conclusion:
During AS, approximately 27% of patients experience mpMRI progression at first repeat MRI. However, the rates of mpMRI progression decrease over time at subsequent mpMRI scans. Patients with stable mpMRI findings and with PSAD < 0.15 ng/mL/mL could safely skip surveillance biopsies. Conversely, patients who experience mpMRI progression should undergo a prostate biopsy.
Insights
Serial multiparametric MRI (mpMRI) can help monitor prostate cancer (PCa) during active surveillance (AS). While mpMRI progression rates decrease over time, criteria like PI-RADS score changes can predict cancer upgrading, guiding biopsy decisions.
Area of Science:
- Urology
- Radiology
- Oncology
Background:
- Active surveillance (AS) is a management strategy for low-risk prostate cancer (PCa).
- Serial multiparametric magnetic resonance imaging (mpMRI) is increasingly used to monitor PCa during AS.
- Assessing mpMRI progression is crucial for guiding treatment decisions and avoiding unnecessary biopsies.
Purpose of the Study:
- To evaluate the rate of upgrading in patients with PCa on AS based on serial mpMRI findings.
- To identify reliable mpMRI criteria for detecting PCa progression during AS.
- To determine the predictive value of mpMRI progression for PCa upgrading.
Main Methods:
- Retrospective analysis of 558 patients undergoing AS for PCa.
- Evaluation of five mpMRI progression criteria: PI-RADS score increase, lesion size increase, extraprostatic extension, overall progression, and number of criteria met.
- Assessment of two PCa upgrading definitions: ISUP Grade Group (GG) ≥2 with >10% pattern 4, and ISUP GG ≥3.
- Analysis of temporal trends, sensitivity, specificity, PPV, and NPV of mpMRI progression criteria.
- Multivariable logistic regression to identify independent predictors of PCa upgrading.
Main Results:
- mpMRI progression rates decreased over time with serial scans.
- The Negative Predictive Value (NPV) of serial mpMRI for PCa upgrading ranged from 90.5% to 99%.
- All five evaluated mpMRI progression criteria were independent predictors of PCa upgrading.
- A prostate-specific antigen density (PSAD) threshold of 0.15 ng/mL/mL was identified for potentially skipping biopsies.
Conclusions:
- Approximately 27% of patients show mpMRI progression at the first repeat scan, with rates decreasing subsequently.
- Stable mpMRI findings and a PSAD < 0.15 ng/mL/mL may allow patients to safely skip surveillance biopsies.
- Patients with evidence of mpMRI progression should be considered for prostate biopsy to assess for cancer upgrading.
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