Improvement of the intermediate risk prostate cancer sub-classification by integrating MRI and fusion biopsy features

MRI characteristics and oncological follow-up of patients with ISUP grade group 4 or 5 prostate cancer

OBJECTIVES

To analyze multiparametric MRI (mpMRI) characteristics of patients with International Society of Urological Pathology (ISUP) grade group (GG) 4 or 5 prostate cancer (PC) and to correlate MRI parameters with the occurrence of biochemical recurrence (BCR) after radical prostatectomy (RPE).

METHODS

In this single-center cohort study consecutive patients with mpMRI and ISUP GG 4 or 5 PC were retrospectively analyzed. Clinical, MR-guided biopsy, and diagnostic mpMRI parameter were assessed. A subcohort of patients with RPE and follow-up was analyzed separately. A univariate and multivariate analyses were performed to determine parameters that are associated to patients with BCR after RPE.

RESULTS

145 patients (mean age 70y, median PSA 10.9 ng/ml) were analyzed. 99% had a PI-RADS classification of 4 or 5, 48% revealed MRI T3 stage, and median diameter of the MRI index lesion (IL) was 15 mm. IL showed a median ADC value of 668 ×10-6 mm2/s and exhibited contrast enhancement in 94% of the cases. For patients with follow-up after RPE (n = 82; mean follow-up time 68 ± 27 m), MRI parameters were significantly different for contact length of the IL to the pseudocapsule (LCC), MRI T3 stage, and IL localization (p < 0.05). Higher PSAD and MRI T3 stage were independent parameters for the risk of BCR when incorporating clinical, biopsy, and MRI parameters.

CONCLUSION

ISUP GG 4 or 5 PC has distinctive characteristics on mpMRI and were detected on MRI in all cases. In addition, higher PSAD and MRI T3 stage were significant predictors for BCR after RPE.

Risk of adverse pathological features for intermediate risk prostate cancer: Clinical implications for definitive radiation therapy

BACKGROUND

Intermediate risk prostate cancer represents a largely heterogeneous group with diverse disease extent. We sought to establish rates of adverse pathological features important for radiation planning by analyzing surgical specimens from men with intermediate risk prostate cancer who underwent immediate radical prostatectomy, and to define clinical pathologic features that may predict adverse outcomes.

MATERIALS AND METHODS

A total of 1552 men diagnosed with intermediate risk prostate cancer who underwent immediate radical prostatectomy between 1/1/2005 and 12/31/2015 were reviewed. Inclusion criteria included available preoperative PSA level, pathology reports of transrectal ultrasound-guided prostate biopsy, and radical prostatectomy. Incidences of various pathological adverse features were evaluated. Patient characteristics and clinical disease features were analyzed for their predictive values.

RESULTS

Fifty percent of men with high risk features (defined as PSA >10 but <20 or biopsy primary Gleason pattern of 4) had pathological upstage to T3 or higher disease. The incidence of upgrade to Gleason score of 8 or higher and the incidence of lymph node positive disease was low. Biopsy primary Gleason pattern of 4, and PSA greater than 10 but less than 20, affected adverse pathology in addition to age and percent positive biopsy cores. Older age and increased percentage of positive cores were significant risk factors of adverse pathology.

CONCLUSION

Our findings underscore the importance of comprehensive staging beyond PSA level, prostate biopsy, and CT/bone scan for men with intermediate risk prostate cancer proceeding with radiation in the era of highly conformal treatment.

Confirmation by Early Oncologic Outcomes After Surgery of the Accuracy of Intermediate-risk Prostate Cancer Classification Based on Magnetic Resonance Imaging Staging and Targeted Biopsy

Over the past decade, prostate cancer (PCa) diagnosis drastically evolved from systematic biopsies (SBs) to multiparametric magnetic resonance imaging (mpMRI) and targeted biopsy (TB), which have emerged as powerful imaging tools for diagnosis, staging, and preoperative planning. MRI and TB should now be widely adopted for assessing prognosis and be incorporated into predictive models. To date, the standard intermediate risk classification (IRC) defined unfavourable and favourable disease with clinical information and overall biopsy data. Roumiguie et al have proposed a new model based on mpMRI staging and grade group on TB and validated it using radical prostatectomy (RP) pathology (Urol Oncol 2020;38:386-92). The aim of our study was to validate the accuracy of this new IRC with early oncologic outcomes and biochemical recurrence (BCR) after RP. From a prospective database of RP patients with positive prebiopsy mpMRI (Prostate Imaging-Reporting and Data System score ≥3) followed by SB in combination with TB, 454 patients with intermediate-risk PCa were included. Median follow-up was 31.5 mo. The new IRC outperformed the standard IRC in predicting BCR (p =  0.007). The area under the curve was 0.613 for the new MRI- and TB-based IRC versus 0.575 for the standard IRC. This new IRC could optimise the prediction of recurrence risk before treatment decision-making.

Patient summary

Outcomes after surgery confirm the accuracy of the new classification of intermediate-risk prostate cancer based on magnetic resonance imaging (MRI) staging and targeted biopsy data. We found that this new classification outperformed the standard classification in predicting biochemical recurrence of cancer for men with positive MRI findings undergoing targeted biopsies.