Materials and Methods: We identified men in the Michigan Urological Surgery Improvement Collaborative registry (46 hospital-based/academic/private practice urology groups) with National Comprehensive Cancer Network (NCCN) low-risk and favorable intermediate-risk prostate cancer who underwent MRI within 6 months before or after initial biopsy and enrolled in AS from June 2016 to January 2021. The primary objective was to determine the association of baseline MRI PI-RADS score (≥4 lesion) with reclassification to high-grade prostate cancer (≥grade group 3) on surveillance biopsy. Multivariable Cox proportional hazards regression models were constructed and adjusted for pathologic, MRI, and clinical/biopsy factors, with landmark time of 6 months from diagnostic biopsy. We included an interaction term between PI-RADS score and NCCN group in the Cox model.
Results: A total of 1491 men were included with median age 64 years (IQR: 59-69) with median follow-up 11.0 months (IQR: 6.0-23.0) after landmark. Baseline PI-RADS ≥ 4 lesion was associated with an increased hazard of biopsy reclassification (HR: 2.3 [95% CI: 1.6-3.2], P < .001), along with grade group 2 vs 1 (HR: 2.5 [95% CI: 1.7-3.7], P < .001), and increasing age (per 10 years; HR: 1.8 [95% CI: 1.4-2.4], P < .001). The interaction between NCCN risk group with MRI findings was not significant (P = .7).
Conclusions: In this multicenter cohort study of real-world data, baseline MRI PI-RADS score was significantly associated with early biopsy reclassification in men undergoing AS with NCCN low- or favorable intermediate-risk prostate cancer.
Active surveillance (AS) is the preferred management strategy for men diagnosed with low-risk prostate cancer and an option for men with favorable intermediate risk per National Comprehensive Cancer Network (NCCN) guidelines.1 While the utilization of AS is growing given the safety and efficacy, the risk of overtreatment and treatment-related side effects needs to be weighed against undertreating occult aggressive disease.2 There is also considerable variation in surveillance schedules and threshold for treatment, which partially arises from the heterogeneous individual outcomes of AS patients.3 In addition to traditional pathologic, clinical staging, and PSA information, MRI and biomarkers are being increasingly utilized to improve risk stratification, with the goal of refining AS selection criteria and tailoring the intensity of follow-up. Currently, NCCN guidelines recommend confirmatory biopsy, MRI, and/or molecular tumor analysis to establish AS appropriateness, with confirmatory testing optional in men with MRI before diagnostic biopsy.1
MRI is a valuable method in discriminating between low-grade and high-grade tumors for AS eligibility, along with conferring results predictive of AS outcomes based on lesion visualization from the Prostate Imaging Reporting and Data System (PI-RADS) score.4,5 However, most previous studies on the prognostic implications of baseline PI-RADS score included smaller populations from academic centers, limited inclusion of clinical and pathologic data into models, and/or ambiguous on the implications of PI-RADS 3 score.6-9 Moreover, limited literature has been published on the role of PI-RADS score stratified by NCCN risk group as predictors of AS outcome.
Data from a real-world, diverse setting regarding the prognostic information from baseline MRI PI-RADS score could potentially improve upfront risk stratification and tailor intensity of surveillance. The purpose of our study was to evaluate the association of baseline PI-RADS score with biopsy reclassification in a multicenter AS cohort.
Kiran R. Nandalur,1 Chen Shen,2 Lili Zhao,2 Sayf Al-Katib,3 Joseph Lee,4 Brian Seifman,5,6 Hong Ye,4 Kevin Ginsburg,7 Thomas Quinn,4 Sirisha Nandalur,4 Arvin George,8 David Gangwish,5 Abhay Dhaliwal,3 Connor Erwin,6 Amanda Young,6 Akram Albeer,6 and Jason Hafron5,6
- Department of Radiology and Molecular Imaging, Corewell Health William Beaumont University Hospital, Oakland University William Beaumont School of Medicine, Royal Oak, MI
- Biostatistics and Health Informatics, Corewell Health Research Institute, Royal Oak, Michigan
- Department of Radiology and Molecular Imaging, Corewell Health William Beaumont University Hospital, Royal Oak, Michigan
- Department of Radiation Oncology, Corewell Health William Beaumont University Hospital, Royal Oak, Michigan
- Department of Urology, Corewell Health William Beaumont University Hospital, Royal Oak, Michigan
- Michigan Institute of Urology, West Bloomfield, Michigan
- Department of Urology, Wayne State University, Detroit, Michigan
- Brady Urological Institute, Johns Hopkins University, Baltimore, Maryland
- Prostate cancer, version 2.2019, NCCN Clinical Practice Guidelines in Oncology. J Natl Compr Canc Netw. 2019; 17(5):479-505. doi:10.6004/jnccn.2019.0023