Prostate MRI: staging and decision-making

Prior MRI-imaging impact of patients submitted to brachytherapy for prostate cancer

INTRODUCTION

Brachytherapy for the treatment of prostate cancer is a well-established option. Use of Multiparametric Magnetic Resonance Imaging (mpMRI) for staging and diagnosis of prostate cancer has come to change the current paradigm. In this study we aim to assess the impact of performing mpMRI to evaluate the presence of extracapsular lesions before brachytherapy in patients with prostate cancer concerning biochemical recurrence and time to nadir.

METHODS

Review data from 73 patients submitted to brachytherapy. The following factors were evaluated: age, initial PSA, MRI local staging results, ISUP, nadir, time to nadir, PSA at one-year, biochemical recurrence, and time to recurrence.

RESULTS

Median age was 68 years (51-72) and median follow-up 53 months (30-72). Concerning imaging modality 30,1% (n = 22) patients performed mpMRI. In the mpMRI group, 90.9% (n = 20) had at least one suspect lesion on mpMRI. Time to nadir was 27 months (3-64) in patients where mpMRI was not performed and 23.5 months (2-48) in patients submitted to mpMRI (P = .244). The median value of nadir was 0.42 ng/mL (<0.001-2) in patients submitted to mpMRI and vs 0.28 ng/mL (<0.001-4) in patients without MRI (P = .062) Recurrence utilizing Phoenix criteria was 9% (n = 2) in patients with MRI and 9.2% (n = 5) without mpMRI (P = .456), median follow-up of 43 months (12-72) for the MRI group with 58 months (30-78) for the non-mpMRI group. Both groups were statistically similar.

CONCLUSION

Our results allow us to conclude that in our series MRI did not influence biochemical recurrence, time to nadir, or nadir value.

Extraprostatic incidental findings on prostate mpMRI: A pictorial review from the ESUR junior network

The role of multiparametric MRI (mpMRI) in prostate cancer setting is increasingly consolidated and, as a result, its usage in clinical practice is in exponential growth. However, beyond the prostate gland, several key structures are included in the field of view of mpMRI scans. Consequently, various extra-prostatic incidental findings (IFs) belonging to different anatomical systems can be accidentally recognized. Therefore, it is mandatory for a radiologist to be familiar with the wide range of pathologies potentially encountered, to guide management and avoid patient anxiety and costs due to additional work-up prompted by clinically insignificant extra-prostatic findings. With this pictorial review, we aim to illustrate a wide range of IFs that can be detected when performing mpMRI of the prostate, focusing on their imaging characteristics, differential diagnosis, and clinical relevance. Additionally, we propose the CheckDEEP, the Checklist for DEtection of ExtraProstatic findings, to be used for a thorough evaluation of target areas within each anatomical system.

Longitudinal evaluation of apparent diffusion coefficient values as a predictor of Prostate Cancer Research International Active Surveillance reclassification

PURPOSE

This study aimed to evaluate the effectiveness of apparent diffusion coefficient (ADC) parameters in distinguishing between Prostate Cancer Research International Active Surveillance (PRIAS) non-reclassification and reclassification groups during active surveillance (AS) of prostate cancer.

METHODS

We included 55 patients who fulfilled the PRIAS criteria and underwent ≥ 2 magnetic resonance imaging (MRI) including diffusion-weighted imaging with an interval of ≤ 3 years between baseline and second MRI. A mono-exponential fitting model was used to automatically create ADC maps with minimum b-values of 0 and maximum of 2000 s/mm². For detectable lesions on ADC maps, the lesions were manually segmented on each slice of the ADC maps. For undetectable lesions, the corresponding normal-appearing zone of the lobe on each slice of ADC maps was segmented. The ADC data for each slice were summed to obtain the 25th, 50th, and 75th percentile ADC values of the histogram at baseline and second MRI. These ADC parameters at baseline and second MRI, and the changes of ADC parameters from baseline to second MRI were compared between PRIAS non-reclassification and reclassification groups.

RESULTS

The PRIAS reclassification group had significantly lower 25th, 50th, and 75th percentile ADC values at second MRI compared to the non-reclassification group. The non-reclassification group had significantly lower changes in ADC values in these percentiles compared to the reclassification group.

CONCLUSION

The ADC parameters at second MRI and the changes from baseline to second MRI may be effective distinguishing factors between PRIAS non-reclassification and reclassification groups.

Periprostatic schwannoma mimicking metastatic lymphadenopathy in a case of multifocal prostate adenocarcinoma

Schwannomas of the prostate are a rare entity and usually diagnosed incidentally following surgical management of presumed benign prostate hyperplasia or prostate adenocarcinoma. We present a case of sporadic periprostatic schwannoma diagnosed in conjunction with multifocal prostate adenocarcinoma on pre-operative multiparametric magnetic resonance imaging.

Multiparametric MRI with in-bore targeted biopsy in the diagnostic pathway of prostate cancer: Data from a single institution experience

BACKGROUND

Accuracy of multiparametric MRI (mpMRI) for the detection of significant prostate cancer (CaP) varies in the literature as only few studies use radical prostatectomy specimens as their gold standard. On another hand, MRI-targeted prostate biopsy is emerging as an alternative to the traditional randomized biopsy, with a higher detection rate of high-grade cancers. However, data on MRI guided in bore biopsy is lacking.

MATERIAL AND METHODS

We reviewed every patient that had his mpMRI, MRI guided in bore biopsy and radical prostatectomy performed in our hospital between November 2015 and December 2020. The diagnostic performances of both mpMRI and MRI targeted biopsy in sampling PIRADS index lesions were studied, using radical prostatectomy specimens as the gold standard. Sensitivity, specificity, positive predictive value and negative predictive value of mpMRI for detecting T3 stage, extra-capsular extension, seminal vesicles involvement and lymph node disease were also evaluated.

RESULTS

Sixty-two met our inclusion criteria. For PIRADS≥3 lesions, sensitivity and positive predictive value for detecting clinically significant CaP were of 83.5% and 94.7%. A total of 32.2% prostate cancers on targeted biopsy were upgraded on final pathology, with an upgrading to ISUP≥2 in 3.2% and to ISUP≥3 in 14.5%. A total of 20.9% of cancers were downgraded but without any downgrading to ISUP 1. When final pathology is taken as a gold standard, sensitivity of mpMRI was 31.8% for T3 staging prediction, 30.0% for extra-capsular extension, 28.7% for seminal vesicles involvement and 66.7% for lymph node disease prediction. Specificity was 89.3%, 93.1%, 95.3%, and 92.7%, respectively.

CONCLUSION

mpMRI has an acceptable accuracy for the prediction of significant CaP and index lesion detection but is unreliable for CaP staging. Comparison between pathology and biopsy results revealed that the in-bore biopsy technique has an upgrading and downgrading rate comparable in the literature to fusion biopsy, but higher than the combined biopsy approach.

Value of clinical parameters and MRI with PI-RADSV2 in predicting seminal vesicle invasion of prostate cancer

OBJECTIVE

To investigate the usefulness of magnetic resonance imaging (MRI) with Prostate Imaging Reporting and Data System version 2 (PI-RADS_V2) and clinical parameters in predicting seminal vesicle invasion (SVI).

MATERIAL AND METHODS

In this retrospective study, we identified 569 prostate cancer patients who underwent radical prostatectomy with MRI before surgery. SVI was interpreted with PI-RADS_V2. Clinical parameters such as the prostate-specific antigen (PSA) and Gleason score (GS) were analyzed for the prediction of SVI. Logistic regression models and receiver operating characteristic (ROC) curves were used to evaluate SVI based on clinical parameters and MRI with PI-RADS_V2.

RESULTS

The median age at presentation was 67 years (43-85 years). The median PSA level was 6.1 ng/mL (2.2-72.8 ng/mL). There were 113 patients with a biopsy GS of ≥ 8. A total of 34 patients (6.0%) were interpreted to have SVI by MRI of which 20 were true positive, and 52 patients (9.1%) had true SVI in the final pathologic analysis. In multivariable analysis, PSA (HR: 1.03, 95% CI: 1.00-1.07), biopsy GS ≥ 8 (HR: 4.14, 95% CI: 2.12-8.09), and MRI with PI-RADS_V2 (HR: 14.67, 95% CI: 6.34-33.93) were significantly associated with pathologic SVI. The area under the curve of the model based on the clinical parameters PSA and GS plus MRI (0.862) was significantly larger than that of the model based on clinical parameters alone (0.777, p < 0.001).

CONCLUSIONS

MRI with PI-RADS_V2 using the clinical parameters PSA and GS was effective in predicting SVI.

Imaging assessment of local recurrence of prostate cancer after radical prostatectomy

Definitive therapy for prostate cancer includes radical prostatectomy and radiation therapy. Treatment is elected based on patient preference, biological tumor factors, and underlying health. Post prostatectomy, men are surveyed for disease recurrence with serial PSA measurements, digital rectal exam, and imaging studies depending on nomogram predicted risk of local disease recurrence and distant metastasis. In men with rising PSA levels, pathologically incomplete surgical margins or, if symptoms of metastasis develop, imaging may be obtained to localize disease. In cases of known biochemical recurrence, imaging is used to target biopsy, to contour in salvage radiation therapy and to assess disease response. For local disease recurrence, the most commonly performed exams are pelvic MRI and transrectal US. CT can evaluate for lymph node metastasis, but is suboptimal in the evaluation of the prostatectomy bed. PET/CT and PET/MRI have been used successfully to evaluate for local disease recurrence. The PI-RADSv2.1 manual provides a risk level and lexicon for use in description of prostate carcinoma prior to prostatectomy, but does not address imaging features post-surgery. A detailed description of nodal, bony, and visceral metastasis is given elsewhere. This manuscript outlines the context in which appropriate imaging exams may be obtained and focuses on imaging findings concerning for local disease recurrence after prostatectomy on various imaging modalities including CT, US, MRI, and PET.