Index lesion contouring on prostate MRI for targeted MRI/US fusion biopsy - Evaluation of mismatch between radiologists and urologists

Association of Pathological Features and Multiparametric MRI-Based Radiomics With TP53-Mutated Prostate Cancer

BACKGROUND

TP53 mutations are associated with prostate cancer (PCa) prognosis and therapy.

PURPOSE

To develop TP53 mutation classification models for PCa using MRI radiomics and clinicopathological features.

STUDY TYPE

Retrospective.

POPULATION

388 patients with PCa from two centers (Center 1: 281 patients; Center 2: 107 patients). Cases from Center 1 were randomly divided into training and internal validation sets (7:3). Cases from Center 2 were used for external validation.

FIELD STRENGTH/SEQUENCE

3.0T/T2-weighted imaging, dynamic contrast-enhanced imaging, diffusion-weighted imaging.

ASSESSMENT

Each patient's index tumor lesion was manually delineated on the above MRI images. Five clinicopathological and 428 radiomics features were obtained from each lesion. Radiomics features were selected by least absolute shrinkage and selection operator and binary logistic regression (LR) analysis, while clinicopathological features were selected using Mann-Whitney U test. Radiomics models were constructed using LR, support vector machine (SVM), and random forest (RF) classifiers. Clinicopathological-radiomics combined models were constructed using the selected radiomics and clinicopathological features with the aforementioned classifiers.

STATISTICAL TESTS

Mann-Whitney U test. Receiver operating characteristic (ROC) curve analysis and area under the curve (AUC). P value <0.05 indicates statistically significant.

RESULTS

In the internal validation set, the radiomics model had an AUC of 0.74 with the RF classifier, which was significantly higher than LR (AUC = 0.61), but similar to SVM (AUC = 0.69; P = 0.422). For the combined model, the AUC of RF model was 0.84, which was significantly higher than LR (0.64), but similar to SVM (0.80; P = 0.548). Both the combined RF and combined SVM models showed significantly higher AUCs than the radiomics models. In the external validation set, the combined RF and combined SVM models showed AUCs of 0.83 and 0.82.

DATA CONCLUSION

Pathological-radiomics combined models with RF, SVM show the association of TP53 mutations and pathological-radiomics features of PCa.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 2.

PIRADS≥4 MRI lesion: Is performing systematic biopsies still essential for detecting clinically significant prostate cancer?

INTRODUCTION

In the era of targeted prostate biopsies, the necessity of performing randomized biopsies systematically is under question. Our objective is to evaluate the rate of clinically significant prostate cancer (csPCa), defined by presence of ISUP≥2 prostate cancer, diagnosed only on randomized cores in case of a PIRADS≥4 target lesion on MRI. The secondary objective is to evaluate whether specific variables can predict the presence of undetected csPCa in targeted biopsies.

METHODS

Retrospective data on targeted biopsies performed from 2015 to 2021 in our hospital were collected. Procedures were performed with MRI/Transrectal US fusion Trinity platform from Koelis®. All the MRI images were reviewed and the targets were classified using the PIRADS V2.1 classification. Inclusion criteria comprised procedures featuring at least one PIRADS≥4 targeted lesion were included. All procedures consisted 1-4 targeted cores and 12-core systematic biopsy.

RESULTS

We included 358 patients. In 44 patients (12.3%) csPCa was exclusively detected in randomized cores. Among these cases, only 12 patients (27.2%) showed no cancer on the targeted biopsies. Merely 4 patients (9.09%) lacked csPCa-positive cores on the same side as the index lesion. Factors such as PSA, PSA density, prostate volume, and digital rectal examination showed no significant association with the presence of csPCa exclusively on randomized cores. Likewise, the size, location, and PIRADS classification of the target demonstrated no significant impact.

CONCLUSION

Our findings indicate that in 12.3% of cases, targeted biopsies alone are insufficient for detecting the presence of csPCa. As such, systematic biopsies remain necessary to date.

LEVEL OF EVIDENCE: 4

Comparison of Targeted Biopsy and Combined Biopsy to Avoid Unnecessary Systematic Biopsy in Patients with PI-RADS 5 Lesions

PURPOSE

To evaluate the detection rates of prostate cancer (PCa) and clinically significant prostate cancer (CSPCa) detection via target biopsy (TB), systematic biopsy (SB), and combined biopsy (CB) in patients with PI-RADS 5 lesions.

METHODS

Patients with at least one PI-RADS 5 lesion were retrospectively enrolled in a prospectively collected database. The patients underwent multiparametric magnetic resonance imaging (mpMRI) followed by transrectal TB of PI-RADS 5 lesions and SB. The PCa and CSPCa detection rates and cores of TB and SB were compared with those of CB.

RESULTS

In 585 patients, prostate biopsy revealed PCa in 560 cases (95.73%) and CSPCa in 549 cases (93.85%). PCa was detected in T2 patients (93.13%, 217/233) and in T3/4 patients (97.44%, 343/352). CSPCa was detected in T2 patients (89.27%, 208/233) and in T3/4 patients (96.87%, 341/352). The positive rates of TB for T2/3/4, T3/4, and T2 were 94.02%, 96.21%, and 90.56%, respectively. SB added 1.71% (10/585) PCa and 1.37% (8/585) CSPCa detection to TB. There was no difference between TB and SB in detecting different stages of cancer (p > 0.05). In the biopsy core analysis, TB had fewer biopsy cores and a higher detection rate than SB (all p < 0.05).

CONCLUSIONS

In patients with PI-RADS score 5 lesions, TB can achieve the same detection rate as, with fewer biopsy cores than, CB. SB adds minimal clinical value and can be omitted for these patients.