Prebiopsy multiparametric MRI and PI-RADS version 2.0 for differentiating histologically benign prostate disease from prostate cancer in biopsies: A retrospective single-center comparison

Magnetic Resonance Imaging, Clinical, and Biopsy Findings in Suspected Prostate Cancer: A Systematic Review and Meta-Analysis

Importance

Multiple strategies integrating magnetic resonance imaging (MRI) and clinical data have been proposed to determine the need for a prostate biopsy in men with suspected clinically significant prostate cancer (csPCa) (Gleason score ≥3 + 4). However, inconsistencies across different strategies create challenges for drawing a definitive conclusion.

Objective

To determine the optimal prostate biopsy decision-making strategy for avoiding unnecessary biopsies and minimizing the risk of missing csPCa by combining MRI Prostate Imaging Reporting & Data System (PI-RADS) and clinical data.

Data Sources

PubMed, Ovid MEDLINE, Embase, Web of Science, and Cochrane Library from inception to July 1, 2022.

Study Selection

English-language studies that evaluated men with suspected but not confirmed csPCa who underwent MRI PI-RADS followed by prostate biopsy were included. Each study had proposed a biopsy plan by combining PI-RADS and clinical data.

Data Extraction and Synthesis

Studies were independently assessed for eligibility for inclusion. Quality of studies was appraised using the Quality Assessment of Diagnostic Accuracy Studies 2 tool and the Newcastle-Ottawa Scale. Mixed-effects meta-analyses and meta-regression models with multimodel inference were performed. Reporting of this study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline.

Main Outcomes and Measures

Independent risk factors of csPCa were determined by performing meta-regression between the rate of csPCa and PI-RADS and clinical parameters. Yields of different biopsy strategies were assessed by performing diagnostic meta-analysis.

Results

The analyses included 72 studies comprising 36 366 patients. Univariable meta-regression showed that PI-RADS 4 (β-coefficient [SE], 7.82 [3.85]; P = .045) and PI-RADS 5 (β-coefficient [SE], 23.18 [4.46]; P < .001) lesions, but not PI-RADS 3 lesions (β-coefficient [SE], -4.08 [3.06]; P = .19), were significantly associated with a higher risk of csPCa. When considered jointly in a multivariable model, prostate-specific antigen density (PSAD) was the only clinical variable significantly associated with csPCa (β-coefficient [SE], 15.50 [5.14]; P < .001) besides PI-RADS 5 (β-coefficient [SE], 9.19 [3.33]; P < .001). Avoiding biopsy in patients with lesions with PI-RADS category of 3 or less and PSAD less than 0.10 (vs <0.15) ng/mL2 resulted in reducing 30% (vs 48%) of unnecessary biopsies (compared with performing biopsy in all suspected patients), with an estimated sensitivity of 97% (vs 95%) and number needed to harm of 17 (vs 15).

Conclusions and Relevance

These findings suggest that in patients with suspected csPCa, patient-tailored prostate biopsy decisions based on PI-RADS and PSAD could prevent unnecessary procedures while maintaining high sensitivity.

Evaluation of Physicochemical Properties, Pharmacokinetics, Biodistribution, Toxicity, and Contrast-Enhanced Cancer MRI of a Cancer-Targeting Contrast Agent, MT218

OBJECTIVES

Preclinical assessments were performed according to the US Food and Drug Administration guidelines to determine the physicochemical properties, pharmacokinetics, clearance, safety, and tumor-specific magnetic resonance (MR) imaging of MT218, a peptidic gadolinium-based MR imaging agent targeting to extradomain B fibronectin for MR molecular imaging of aggressive tumors.

MATERIALS AND METHODS

Relaxivity, chelation stability, binding affinity, safety-related target profiling, and effects on CYP450 enzymes and transporters were evaluated in vitro. Magnetic resonance imaging was performed with rats bearing prostate cancer xenografts, immunocompetent mice bearing murine pancreatic cancer allografts, and mice bearing lung cancer xenografts at different doses of MT218. Pharmacological effects on cardiovascular, respiratory, and central nervous systems were determined in rats and conscious beagle dogs. Pharmacokinetics were tested in rats and dogs. Biodistribution and excretion were studied in rats. Single and repeated dosing toxicity was evaluated in rats and dogs. In vitro and in vivo genotoxicity, in vitro hemolysis, and anaphylactic reactivity were also performed.

RESULTS

At 1.4 T, the r1 and r2 relaxivities of MT218 were 5.43 and 7.40 mM -1 s -1 in pure water, 6.58 and 8.87 mM -1 s -1 in phosphate-buffered saline, and 6.54 and 8.70 mM -1 s -1 in aqueous solution of human serum albumin, respectively. The binding affinity of MT218 to extradomain B fragment is 3.45 μM. MT218 exhibited no dissociation of the Gd(III) chelates under physiological conditions. The peptide degradation half-life ( t1/2 ) of MT218 was 1.63, 5.85, and 2.63 hours in rat, dog, and human plasma, respectively. It had little effect on CYP450 enzymes and transporters. MT218 produced up to 7-fold increase of contrast-to-noise ratios in the extradomain B fibronectin-rich tumors with a dose of 0.04 mmol/kg for at least 30 minutes. MT218 had little pharmacological effect on central nervous, cardiovascular, or respiratory systems. MT218 had a mean plasma elimination half-life ( t1/2 ) of 0.31 and 0.89 hours in rats and dogs at 0.1 mmol/kg, respectively. No detectable Gd deposition was observed in the brain at 6 hours postinjection of MT218 at 0.1 mmol/kg in rats. MT218 was not mutagenic and had no mortality or morbidity in the rats or dogs up to 1.39 and 0.70 mmol/kg/d, respectively. The no observed adverse effect level of MT218 in Sprague-Dawley rats was 1.39 mmol/kg for single dosing and 0.46 mmol/kg/d for repeated dosing. The no observed adverse effect level in dogs was 0.07 mmol/kg/d. MT218 exhibited no genotoxicity, hemolysis, and anaphylactic reactivity.

CONCLUSION

The preclinical assessments showed that the targeted contrast agent MT218 has high r1 and r2 relaxivities, satisfactory physicochemical properties, pharmacokinetic, and safety profiles and produces effective tumor enhancement in multiple cancer types in rats and mice at reduced doses.

Which measurement method should be used for prostate volume for PI-RADS? A comparison of ellipsoid and segmentation methods

PURPOSE

Prostate volume and PSA density (PSAd) are important in the risk stratification of suspected prostate cancer (Pca). PI-RADS v2.1 allows for determining volume via segmentation or ellipsoid calculation. The purpose of our study was to compare ellipsoid and segmentation volume calculation methods and evaluate if PSAd diagnostic performance is altered.

METHODS

We retrospectively assessed 397 patients (mean age/standard deviation: 63.7/7.4 years) who underwent MRI and prostate biopsy or prostatectomy, with Pca classified by Gleason ≥3 + 4 and ≥4 + 4 disease. Prostate total volumes were determined with ellipsoid calculations (TVe) and with semi-automated segmentation (TVs), along with inter-rater reliability with intraclass correlation coefficient (ICC). PSAd was calculated for TVe and TVs and ROC curves were created to compare performance for Gleason ≥3 + 4 and ≥4 + 4 disease.

RESULTS

TVe was significantly higher than TVs (p < 0.0001), with mean TVe = 55.4 mL and TVs = 51.0 mL. ROC area under the curve for PSAd derived with TVe (0.63, 95%CI:0.59-0.68) and TVs (0.64, 95%CI:0.59-0.68) showed no significant difference for Gleason ≥3 + 4 disease (p = 0.45), but PSAd derived with TVs (0.63, 95%CI: 0.58-0.68) significantly outperformed TVe (0.61, 95%CI: 0.57-0.67) for Gleason ≥4 + 4 disease (p = 0.02). Both methods demonstrated excellent inter-rater reliability with TVe with ICC of 0.93(95%CI: 0.92-0.94) and TVs with ICC of 0.98(95%CI: 0.98-0.99).

CONCLUSION

Traditional ellipsoid measurements tend to overestimate total prostate volume compared to segmentation, but both methods demonstrate similar diagnostic performance of derived PSA density for PI-RADS clinically significant disease. For higher grade disease, PSAd derived from segmentation volumes demonstrates statistically significant superior performance. Both methods are viable, but segmentation volume is potentially better.