INTRODUCTION AND OBJECTIVE:
Digital rectal examination (DRE) is a well-established prognostic indicator for biochemical recurrence (BCR) in prostate cancer (PCa) patients considered for radical prostatectomy (RP). The introduction of multiparametric MRI (mpMRI) can improve the ability to preoperatively identify men with extracapsular extension (ECE). However, little is known about the added value of mpMRI according to different stage at DRE and this is what we aimed to explore.
2,098 patients with PCa treated with RP between 2015 and 2020 at seven referral centers were identied. All men had available data on clinical stage determined at DRE performed by the attending urologist and complete MRI data. BCR was dened as two PSA ≥0.2 ng/ml after RP. Patients were stratied in cT1c, cT2 and cT3 stages at DRE. We tested whether the presence of ECE at mpMRI impacted on BCR within each cT group. Kaplan-Meier (KM) analyses assessed time to BCR. Multivariable Cox regression models (MVA) tested the added value of MRI within each cT stage in predicting BCR. Covariates were PIRADS group, PSA level and biopsy grade group (GG)
Overall, 1,231 (59%), 762 (36%) and 104 (5%) patients had cT1c, cT2 and cT3 disease at DRE. Among these, mpMRI detected an ECE in 94 patients with cT1c, in 96 patients with cT2 and in 77 patients with cT3. 1,006 patients (48%) had ECE at RP specimen. Median follow-up was 34 mo and 240 patients experienced BCR. The 3- year BCR-free survival rate was 84%. Patients with cT1c and cT2 diseases and concomitant ECE at mpMRI had lower 3-yr BCR-free survival rates compared to their counterparts with organ-conned PCa at MRI (90 vs 78% and 84 vs 69%; all p<0.001). ECE at mpMRI was also associated with worse outcomes in patients with cT3 disease at univariable KM analysis (79 vs 65%; p=0.038). At MVA, mpMRI improved the prediction of BCR according to cT stage, where the presence of ECE at mpMRI was associated with increased risk of BCR in both cT1c (HR 1.71, p=0.003) and cT2 (HR 1.52, p=0.02) disease. The inclusion of mpMRI data improved the discrimination (c-index) of models predicting BCR from 66 to 71%. Conversely, when adjusting for covariates, a positive MRI for ECE did not signicantly increased the risk of recurrence in patients with cT3 (HR 1.83, p=0.1).
We demonstrated that MRI adds important predictive value to DRE in patients with organ conned PCa only. ECE at mpMRI was indeed associated with higher risk of BCR in patients with organ conned palpable or unpalpable lesions at DRE. On the other hand, the added value of MRI in patients with suspected locally advanced disease (cT3) at DRE was limited. Therefore, MRI does not add staging information in these patients and its use might not be routinely recommended for staging purposes in men with locally advanced PCa.
Source of Funding: