Multiparametric magnetic resonance imaging facilitates reclassification during active surveillance for prostate cancer

Abstract

Objective To investigate the utility of multiparametric magnetic resonance imaging (mpMRI) in the reassessment and monitoring of patients on active surveillance (AS) for Grade Group (GG) 1 prostate cancer (PCa). Patients and Methods We identified, from our prospectively maintained institutional review board‐approved database, 181 consecutive men enrolled on AS for GG 1 PCa who underwent at least one surveillance mpMRI followed by MRI/prostate biopsy (PBx). A subset analysis was performed among 68 patients who underwent serial (at least two) mpMRI/PBx during AS. Pathological progression (PP) was defined as upgrade to GG ≥2 on follow up biopsy. Results Baseline MRI was performed in 34 patients (19%). At a median follow‐up of 2.2 years for the overall cohort, the PP was 12% (6/49) for Prostate Imaging Reporting and Data System (PI‐RADS) 1–2 lesions and 37% (48/129) for the PI‐RADS ≥3 lesions. The 2‐year PP‐free survival rate was 84%. Surveillance prostate‐specific antigen density (P < 0.001) and surveillance PI‐RADS ≥3 (P = 0.002) were independent predictors of PP on reassessment MRI/PBx. In the serial MRI cohort, the 2‐year PP‐free survival was 95% for the No‐MRI‐progression group vs 85% for the MRI‐progression group (P = 0.02). MRI progression was significantly higher in the PP (62%) than in the No‐PP (31%) group (P = 0.04). If serial MRI were used for PCa surveillance and biopsy were triggered based only on MRI progression, 63% of PBx might be postponed at the cost of missing 12% of GG ≥2 PCa in those with stable MRI. Conversely, this strategy would miss 38% of those with upgrading to GG ≥2 PCa on biopsy. Stable serial mpMRI correlates with no reclassification to GG ≥3 PCa during AS. Conclusion On surveillance mpMRI, PI‐RADS ≥3 was associated with increased risk of PCa reclassification. Surveillance biopsy based only on MRI progression may avoid a large number of biopsies at the cost of missing many PCa reclassifications.

Repeat MRI during active surveillance: natural history of prostatic lesions and upgrading rates

“…However, the observed trends over time could be a product of the definitions used for the five different mpMRI progression criteria. However, it should be stated that these definitions are consistent with other analyses that focused on the same topic [7,10].…”

“…mpMRI has been proposed as an alternative for monitoring PCa progression [5,6]. However, conflicting results have previously been observed in several AS cohorts that investigated the reliability of repeat mpMRI over time [7][8][9][10][11][12][13][14][15][16][17]. Because of the lack of robust data to support the use of serial mpMRI during AS, we assessed mpMRI diagnostic accuracy in the largest series to date (n = 558) of AS patients who were submitted to confirmatory mpMRI at start of AS and followed up with scheduled repeat © 2021 The Authors BJU International © 2021 BJU International 527 mpMRI scans.…”

“…Moreover, 534 (95.7%) vs 22 (3.9%) vs 2 (0.4%) mpMRI lesions had an EPE score ≤ 2 vs 3 vs 4. The median (interquartile range [IQR]) mpMRI lesion size was 8.5 (7)(8)(9)(10)(11) mm (Table 1).…”

“…However, it remains unclear whether mpMRI can safely replace repeat biopsies during follow-up [5,6]. To date, conflicting results have been reported in previous analyses that assessed the diagnostic accuracy of serial mpMRI scans in men on AS [7][8][9][10][11][12][13][14][15][16][17]. However, most of these studies were limited by the low number of patients enrolled [7,8,13,15,16] or by short followup time [9,[15][16][17].…”

“…To date, conflicting results have been reported in previous analyses that assessed the diagnostic accuracy of serial mpMRI scans in men on AS [7][8][9][10][11][12][13][14][15][16][17]. However, most of these studies were limited by the low number of patients enrolled [7,8,13,15,16] or by short followup time [9,[15][16][17]. Moreover, only few previous analyses focused on the natural history of mpMRI prostatic lesions over time and these found a small annual growth rate in most cases [18,19].…”