Detection of clinically significant prostate cancer with 18F-DCFPyL PET/multiparametric MR

Focal therapy for prostate cancer

Traditional treatments for localized prostate cancer include radical prostatectomy or radiation therapy but pose challenges due to treatment related side effects, namely erectile dysfunction and urinary incontinence. In recent years, focal therapy has emerged as a viable treatment option for localized low-intermediate risk prostate cancer in carefully selected patients. Short and medium-term studies show acceptable cancer control outcomes and reduced morbidity when comparing focal therapy to whole gland treatment for prostate cancer, however there is paucity of long-term studies. Here we review focal ablative therapies commonly used, discuss the role of imaging in monitoring treatment, and summarize oncologic outcomes based on studies to date.

Diagnostic Accuracy of PSMA PET-Guided Prostate Biopsy in Prostate Cancer-A Systematic Review and Meta-analysis

PURPOSE

Early diagnosis and treatment of prostate cancer (PC) are crucial for effective management and improved patient outcomes. Newer imaging modalities like prostate-specific membrane antigen PET have shown superior diagnostic performance in detecting PC and clinically significant PC (csPC). This systematic review and meta-analysis aims to synthesize evidence on the diagnostic performance of PSMA PET-guided prostate biopsy in detecting PC and csPC.

PATIENTS AND METHODS

The study followed the PRISMA-DTA guidelines. Using a predefined search strategy, 3 databases (PubMed, Embase, and Web of Science) were systematically searched using appropriate keywords. A meta-analysis was conducted using diagnostic accuracy parameters of the included studies. Risk of bias assessment was done using the QUADAS-2 tool.

RESULTS

Out of 378 articles, 20 were assessed for full-text screening and 10 articles with 874 patients were finally included. Eight studies reported a pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio of 0.90 (95%confidence interval [CI], 0.82-0.95), 0.93 (95% CI, 0.57-0.99), 12.3 (95% CI, 1.5-98.9), 0.10 (95% CI, 0.05-0.20), and 117 (95% CI, 12-1178), respectively, for detecting PC using PSMA PET-guided prostate biopsy with an area under the summary receiver operating characteristics curve of 0.94 (95% CI, 0.92-0.96). Similarly, 6 studies reported a pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio of 0.89 (95% CI, 0.82-0.94), 0.65 (95% CI, 0.49-0.79), 2.6 (95% CI, 1.6-4.1), 0.17 (95% CI, 0.09-0.31), and 15 (95% CI, 6-41), respectively, for detecting csPC using PSMA PET-guided prostate biopsy with area under summary receiver operating characteristics curve of 0.86 (95% CI, 0.82-0.88).

CONCLUSIONS

PSMA PET-guided prostate biopsy has a high diagnostic accuracy in detecting PC and csPC in patients with clinical suspicion of PC, and provides a 1-stop solution for early diagnosis and staging of PC.

Fluorine-18-labelled Prostate-specific Membrane Antigen Positron Emission Tomography/Computed Tomography or Magnetic Resonance Imaging to Diagnose and Localise Prostate Cancer. A Prospective Single-arm Paired Comparison (PEDAL)

BACKGROUND AND OBJECTIVE

Multiparametric magnetic resonance imaging (mpMRI) of the prostate is used for prostate cancer diagnosis. However, mpMRI has lower sensitivity for small tumours. Prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA-PET/CT) offers increased sensitivity over conventional imaging. This study aims to determine whether the diagnostic accuracy of 18F-DCFPyL PSMA-PET/CT was superior to that of mpMRI for detecting prostate cancer (PCa) at biopsy.

METHODS

Between 2020 and 2021, a prospective multicentre single-arm phase 3 imaging trial enrolled patients with clinical suspicion for PCa to have both mpMRI and PSMA-PET/CT (thorax to thigh), with reviewers blinded to the results of other imaging. Multiparametric MRI was considered positive for Prostate Imaging Reporting and Data System (PIRADS) 3-5. PSMA-PET/CT was assessed quantitatively (positive maximum standardised uptake value [SUVmax] >7) and qualitatively (five-point lexicon of certainty). Patients underwent targeted and systematic biopsy, with the technique at the discretion of the treating urologist. Clinically significant PCa (csPCa) was defined as International Society of Urological Pathology grade group (GG) ≥2. The primary outcome was the diagnostic accuracy for detecting PCa, reported as sensitivity, specificity, negative predictive value (NPV), and area under the curve (AUC) of the receiver operating curve. The secondary endpoints included a comparison of the diagnostic accuracy for detecting csPCa, assessing gains in combining PMSA-PET/CT with mpMRI to mpMRI alone.

KEY FINDINGS AND LIMITATIONS

Of the 236 patients completing both mpMRI and PSMA-PET/CT, 184 (76.7%) had biopsy. Biopsy histology was benign (n = 73), GG 1 (n = 27), and GG ≥2 (n = 84). The diagnostic accuracy of mpMRI for detecting PCa (AUC 0.76; 95% confidence interval [CI] 0.69, 0.82) was higher than that of PSMA-PET/CT (AUC 0.63; 95% CI 0.56, 0.70, p = 0.03). The diagnostic accuracy of mpMRI for detecting csPCa (AUC 0.72; 95% CI 0.67, 0.78) was higher than that of PSMA-PET/CT (AUC 0.62; 95% CI 0.55, 0.69) but not statistically significant (p = 0.27). A combination of PSMA-PET/CT and mpMRI showed excellent sensitivity (98.8%, 95% CI 93.5%, 100%) and NPV (96%, 95% CI 79.6%, 99.9%) over mpMRI alone (86.9% and 80.7%, respectively, p = 0.01). Thirty-two patients (13.6%) had metastatic disease. They tended to be older (68.4 vs 65.1 yr, p = 0.023), and have higher prostate-specific antigen (PSA; median PSA 9.6 vs 6.2ng/ml, p < 0.001) and abnormal prostate on digital rectal examination (78.2% vs 44.1%, p < 0.001).

CONCLUSIONS AND CLINICAL IMPLICATIONS

Multiparametric MRI had superior diagnostic accuracy to PSMA-PET/CT for detecting PCa, though the difference is not significant in case of csPCa detection. A combination of mpMRI and PSMA-PET/CT showed improved sensitivity and NPV. PSMA-PET/CT could be considered for diagnostic use in patients unable to have mpMRI or those with concerning clinical features but negative mpMRI.

PATIENT SUMMARY

In this trial, we compared the ability of 18F-labelled prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA-PET/CT) with that of multiparametric magnetic resonance imaging (mpMRI) to diagnose prostate cancer by biopsy in a prostate-specific antigen screening population. We found that MRI was superior to PSMA to diagnose prostate cancer, though there was no difference in ability to diagnose clinically significant prostate cancer. PSMA-PET/CT could be considered for diagnostic use in patients unable to have mpMRI or those with concerning clinical features but negative mpMRI. Combining MRI with PSMA-PET increases the negative predictive value over MRI alone and may help men avoid invasive prostate biopsy.

Comparison of Multiparametric MRI and the Combination of PSMA Plus MRI for the Intraprostatic Diagnosis of Prostate Cancer: A Systematic Review and Meta-Analysis

PURPOSE

The aim of this study was to perform a head-to-head comparison of multiparametric MRI (mpMRI) and the combination of prostate-specific membrane antigen (PSMA) PET plus MRI (PSMA + MRI) for detecting intraprostatic clinically significant prostate cancer (csPCa).

PATIENTS AND METHODS

Relevant databases were searched through November 2023. Only studies directly comparing mpMRI and PSMA + MRI (PET/MRI or PET/CT + mpMRI) were included. A meta-analysis with a random-effects model was used to estimate pooled sensitivity, specificity, and area under the curve for each approach.

RESULTS

A total of 19 studies were included. On a patient-level analysis, PSMA + MRI had higher sensitivity (9 studies) than mpMRI for csPCa detection (96% [95% confidence interval (CI): 92%, 98%] vs 89% [95% CI: 81%, 94%]; P = 0.04). The patient-level specificity (4 studies) of PSMA + MRI was 55% (95% CI: 31%-76%) compared with 50% (95% CI: 44%-57%) of mpMRI ( P = 0.67). Region-level sensitivity (10 studies) was 85% (95% CI: 74%-92%) for PSMA + MRI and 71% (95% CI: 58%-82%) for mpMRI ( P = 0.09), whereas specificity (4 studies) was 87% (95% CI: 76%-94%) and 90% (95% CI: 82%-95%), respectively ( P = 0.59). Lesion-level sensitivity and specificity were similar between modalities with pooled data from less than 4 studies.

CONCLUSIONS

PSMA + MRI had superior pooled sensitivity and similar specificity for the detection of csPCa compared with mpMRI in this meta-analysis of head-to-head studies.

Head-to-head comparison of prostate-specific membrane antigen PET and multiparametric MRI in the diagnosis of pretreatment patients with prostate cancer: a meta-analysis

OBJECTIVES

To compare prostate-specific membrane antigen (PSMA) PET with multiparametric MRI (mpMRI) in the diagnosis of pretreatment prostate cancer (PCa).

METHODS

Pubmed, Embase, Medline, Web of Science, and Cochrane Library were searched for eligible studies published before June 22, 2022. We assessed risk of bias and applicability by using QUADAS-2 tool. Data synthesis was performed with Stata 17.0 software, using the "midas" and "meqrlogit" packages.

RESULTS

We included 29 articles focusing on primary cancer detection, 18 articles about primary staging, and two articles containing them both. For PSMA PET versus mpMRI in primary PCa detection, sensitivities and specificities in the per-patient analysis were 0.90 and 0.84 (p<0.0001), and 0.66 and 0.60 (p <0.0001), and in the per-lesion analysis they were 0.79 and 0.78 (p <0.0001), and 0.84 and 0.82 (p <0.0001). For the per-patient analysis of PSMA PET versus mpMRI in primary staging, sensitivities and specificities in extracapsular extension detection were 0.59 and 0.66 (p =0.005), and 0.79 and 0.76 (p =0.0074), and in seminal vesicle infiltration (SVI) detection they were 0.51 and 0.60 (p =0.0008), and 0.93 and 0.96 (p =0.0092). For PSMA PET versus mpMRI in lymph node metastasis (LNM) detection, sensitivities and specificities in the per-patient analysis were 0.68 and 0.46 (p <0.0001), and 0.91 and 0.90 (p =0.81), and in the per-lesion analysis they were 0.67 and 0.36 (p <0.0001), and 0.99 and 0.99 (p =0.18).

CONCLUSION

PSMA PET has higher diagnostic value than mpMRI in the detection of primary PCa. Regarding the primary staging, mpMRI has potential advantages in SVI detection, while PSMA PET has relative advantages in LNM detection.

CLINICAL RELEVANCE STATEMENT

The integration of prostate-specific membrane antigen (PSMA) PET into the diagnostic pathway may be helpful for improving the accuracy of prostate cancer detection. However, further studies are needed to address the cost implications and evaluate its utility in specific patient populations or clinical scenarios. Moreover, we recommend the combination of PSMA PET and mpMRI for cancer staging.

KEY POINTS

• Prostate-specific membrane antigen PET has higher sensitivity and specificity for primary tumor detection in prostate cancer compared to multiparametric MRI. • Prostate-specific membrane antigen PET also has significantly better sensitivity and specificity for lymph node metastases of prostate cancer compared to multiparametric MRI. • Multiparametric MRI has better accuracy for extracapsular extension and seminal vesicle infiltration compared to ate-specific membrane antigen PET.

Multiparametric MRI and 18F-PSMA-1007 PET/CT for the Detection of Clinically Significant Prostate Cancer

Background Multiparametric MRI (mpMRI) is effective for detecting prostate cancer (PCa); however, there is a high rate of equivocal Prostate Imaging Reporting and Data System (PI-RADS) 3 lesions and false-positive findings. Purpose To investigate whether fluorine 18 (18F) prostate-specific membrane antigen (PSMA) 1007 PET/CT after mpMRI can help detect localized clinically significant PCa (csPCa), particularly for equivocal PI-RADS 3 lesions. Materials and Methods This prospective study included participants with elevated prostate-specific antigen (PSA) levels referred for prostate mpMRI between September 2020 and February 2022. 18F-PSMA-1007 PET/CT was performed within 30 days of mpMRI and before biopsy. PI-RADS category and level of suspicion (LOS) were assessed. PI-RADS 3 or higher lesions at mpMRI and/or LOS 3 or higher lesions at 18F-PSMA-1007 PET/CT underwent targeted biopsies. PI-RADS 2 or lower and LOS 2 or lower lesions were considered nonsuspicious and were monitored during a 1-year follow-up by means of PSA testing. Diagnostic accuracy was assessed, with histologic examination serving as the reference standard. International Society of Urological Pathology (ISUP) grade 2 or higher was considered csPCa. Results Seventy-five participants (median age, 67 years [range, 52-77 years]) were assessed, with PI-RADS 1 or 2, PI-RADS 3, and PI-RADS 4 or 5 groups each including 25 participants. A total of 102 lesions were identified, of which 80 were PI-RADS 3 or higher and/or LOS 3 or higher and therefore underwent targeted biopsy. The per-participant sensitivity for the detection of csPCa was 95% and 91% for mpMRI and 18F-PSMA-1007 PET/CT, respectively, with respective specificities of 45% and 62%. 18F-PSMA-1007 PET/CT was used to correctly differentiate 17 of 26 PI-RADS 3 lesions (65%), with a negative and positive predictive value of 93% and 27%, respectively, for ruling out or detecting csPCa. One additional significant and one insignificant PCa lesion (PI-RADS 1 or 2) were found at 18F-PSMA-1007 PET/CT that otherwise would have remained undetected. Two participants had ISUP 2 tumors without PSMA uptake that were missed at PET/CT. Conclusion 18F-PSMA-1007 PET/CT showed good sensitivity and moderate specificity for the detection of csPCa and ruled this out in 93% of participants with PI-RADS 3 lesions. Clinical trial registration no. NCT04487847 © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Turkbey in this issue.

Diagnostic performance of 18F‑DCFPyL PET vs. 68Ga‑PSMA PET/CT in patients with suspected prostate cancer: A systemic review and meta‑analysis

In this systematic review and meta-analysis, the diagnostic performance of 68Ga-prostate-specific membrane antigen (PSMA) positron emission tomography (PET)/CT was compared with that of 18F-DCFPyL PET for patients with suspected prostate cancer (PCa). Up to September 2023, the PubMed, Embase and Web of Science databases were thoroughly searched for relevant papers. Studies examining the diagnostic performance of 18F-DCFPyL PET and 68Ga-PSMA PET/CT in patients with suspected PCa were included in the present review. The Quality Assessment of Diagnostic Performance Studies-2 tool was used to rate the diagnostic performance of each study. The diagnostic performance of 18F-DCFPyL PET and 68Ga-PSMA PET/CT for primary PCa was examined by 13 studies included, comprising 1,178 patients. The pooled sensitivity and specificity of 18F-DCFPyL PET were 0.92 (95% CI, 0.85-0.96) and 0.59 (95% CI, 0.08-0.96), respectively. For 68Ga-PSMA PET/CT, the pooled sensitivity and specificity were 0.96 (95% CI, 0.88-0.99) and 0.71 (95% CI, 0.57-0.82), respectively. 18F-DCFPyL PET and 68Ga-PSMA PET/CT both had an area under the receiver operating characteristic curve of 0.92 (95% CI, 0.89-0.94). In addition, the Fagan nomogram revealed that the post-test probabilities for 18F-DCFPyL PET and 68Ga-PSMA PET/CT could rise to 69 and 77% when the pre-test probability was set at 50%. In conclusion, a comparable diagnostic performance for patients with suspected PCa was determined for 18F-DCFPyL PET and 68Ga-PSMA PET/CT. However, it is crucial to keep in mind that the findings of the present meta-analysis come from investigations with modest sample sizes. Therefore, more extensive research is required to obtain more solid data.

Prognostic Value of PSMA PET/CT in Prostate Cancer

Prostate-specific membrane antigen (PSMA) is a transmembrane glycoprotein expressed in the majority of prostate cancer (PCa). PSMA has an enzymatic function that makes metabolic substrates such as folate available for utilization by PCa cells. Intracellular folate availability drives aggressive tumor phenotype. PSMA expression is, therefore, a marker of aggressive tumor biology. The large extracellular domain of PSMA is available for targeting by diagnostic and therapeutic radionuclides, making it a suitable cellular epitope for theranostics. PET imaging of radiolabeled PSMA ligands has several prognostic utilities. In the prebiopsy setting, intense PSMA avidity in a prostate lesion correlate well with clinically significant PCa (csPCa) on histology. When used for staging, PSMA PET imaging outperforms conventional imaging for the accurate staging of primary PCa, and findings on imaging predict post-treatment outcomes. The biggest contribution of PSMA PET imaging to PCa management is in the biochemical recurrence setting, where it has emerged as the most sensitive imaging modality for the localization of PCa recurrence by helping to guide salvage therapy. PSMA PET obtained for localizing the site of recurrence is prognostic, such that a higher lesion number predicts a less favorable outcome to salvage radiotherapy or surgical intervention. Systemic therapy is given to patients with advanced PCa with distant metastasis. PSMA PET is useful for predicting response to treatments with chemotherapy, first- and second-line androgen deprivation therapies, and PSMA-targeted radioligand therapy. Artificial intelligence using machine learning algorithms allows for the mining of information from clinical images not visible to the human eyes. Artificial intelligence applied to PSMA PET images, therefore, holds great promise for prognostication in PCa management.

Systematic Review and Metanalysis on the Role of Prostate-Specific Membrane Antigen Positron Emission Tomography/Magnetic Resonance Imaging for Intraprostatic Tumour Assessment

The present systematic review and meta-analysis are focused on the diagnostic accuracy of PSMA PET/MRI in primary prostate cancer assessment. A literature search was conducted on the PubMed database using the terms "PSMA" AND "prostate cancer" or "prostate" AND "PET/MRI" or "PET MRI" or "PET-MRI" or "PET-MR" AND "primary" or "staging." Ten articles were eligible for analysis after applying the exclusion criteria. PET/MRI showed better diagnostic accuracy in detecting primary PCa compared to multiparametric (mp) MRI and PET alone. The pooled sensitivity and specificity of 68Ga-PSMA PET/MRI at the per-patient level were 0.976 (CI: 0.943-0.991) and 0.739 (CI: 0.437-0.912); respectively. PSMA PET/MRI has good sensitivity in detecting primary PCa, especially in patients with PIRADS 3 PCa.

Impact of 18F-DCFPyL PET/MRI in Selecting Men With Low-/Intermediate-Risk Prostate Cancer for Focal Ablative Therapies

PURPOSE

To compare the diagnostic performance of multiparametric (mp) MRI to 18F-DCFPyL PET/MRI for detecting clinically significant (cs) prostate cancer (PCa) in men with low-/intermediate-risk PCa being considered for focal ablative therapy (FT), using 2 interpretation schemes, and to assess the rate of exclusion from FT for each modality.

METHODS

This prospective study evaluated men with low- or intermediate-risk PCa, potential candidates for FT based on initial biopsy as per institutional protocol, who underwent 18F-DCFPyL PET/MRI. Each modality (mpMRI, PET/MRI using PROMISE classification [PET/MRI PROMISE], and PET/MRI considering any focal lesion on PET as positive [PETFL/MRI]) was assessed independently. All suspicious lesions underwent PET/MRI-ultrasound fusion biopsies. Diagnostic performances were calculated and compared using the exact binomial test on paired proportions.

RESULTS

Thirty-four men (median age, 64 years; interquartile range, 60-70 years) were included. Overall, 40 of 67 lesions (60%) identified on mpMRI and/or PET/MRI were malignant, and 34 of 40 lesions (85%) were csPCa (≥6 mm ISUP [International Society of Urological Pathology Grade Group] GG1 or ISUP-GG ≥2). On lesion-level analysis, for detecting csPCa, sensitivity appeared higher for PETFL/MRI than mpMRI and PET/MRI PROMISE (97% vs 76% and 79%, respectively [P = 0.02 and 0.03]), whereas specificity was lower (30% vs 85% and 88%, respectively [P < 0.001]). The calculated overall accuracy rates for PETFL/MRI, mpMRI, and PET/MRI PROMISE were 64%, 81%, and 84%, respectively. PETFL/MRI, mpMRI, and PET/MRI PROMISE excluded 10 of 34 (29%), 7 of 34 (21%), and 6 of 34 (18%) men from FT, respectively.

CONCLUSIONS

18F-DCFPyL PET/MRI excluded nearly 30% of patients with low-/intermediate-risk PCa from FT, with a potential role in decreasing selection failure. Compared with mpMRI, PET/MRI had a higher sensitivity for detecting csPCa in men who were candidates for FT.ClinicalTrials.gov identifier NCT03149861.

Comparing the Detection Performance Between Multiparametric Magnetic Resonance Imaging and Prostate-Specific Membrane Antigen PET/CT in Patients With Localized Prostate Cancer: A Systematic Review and Meta-analysis

PURPOSE

Multiparametric MRI (mpMRI) has been promoted as an auxiliary diagnostic tool for prostate biopsy. However, prostate-specific membrane antigen (PSMA) including 68 Ga-PSMA-11, 18 F-DCFPyL, and 18 F-PSMA-1007 applied PET/CT imaging was an emerging diagnostic tool in prostate cancer patients for staging or posttreatment follow-up, even early detecting. Many studies have used PSMA PET for comparison with mpMRI to test the diagnostic ability for early prostate cancer. Unfortunately, these studies have shown conflicting results. This meta-analysis aimed to compare the differences in diagnostic performance between PSMA PET and mpMRI for detecting and T staging localized prostatic tumors.

METHODS

This meta-analysis involved a systematic literature search of PubMed/MEDLINE and Cochrane Library databases. The pooling sensitivity and specificity of PSMA and mpMRI verified by pathological analysis were calculated and used to compare the differences between the 2 imaging tools.

RESULTS

Overall, 39 studies were included (3630 patients in total) from 2016 to 2022 in the current meta-analysis and found that the pooling sensitivity values for localized prostatic tumors and T staging T3a and T3b of PSMA PET were 0.84 (95% confidence interval [CI], 0.83-0.86), 0.61 (95% CI, 0.39-0.79), and 0.62 (95% CI, 0.46-0.76), respectively, whereas those of mpMRI were found to be 0.84 (95% 0.78-0.89), 0.67 (95% CI, 0.52-0.80), and 0.60 (95% CI, 0.45-0.73), respectively, without significant differences ( P > 0.05). However, in a subgroup analysis of radiotracer, the pooling sensitivity of 18 F-DCFPyL PET was higher than mpMRI (relative risk, 1.10; 95% CI, 1.03-1.17; P < 0.01).

CONCLUSIONS

This meta-analysis found that whereas 18 F-DCFPyL PET was superior to mpMRI at detecting localized prostatic tumors, the detection performance of PSMA PET for localized prostatic tumors and T staging was comparable to that of mpMRI.

The role of [18F]-DCFPyL PET/MRI radiomics for pathological grade group prediction in prostate cancer

PURPOSE

To evaluate the diagnostic accuracy of [18F]-DCFPyL PET/MRI radiomics for the prediction of pathological grade group in prostate cancer (PCa) in therapy-naïve patients.

METHODS

Patients with confirmed or suspected PCa, who underwent [18F]-DCFPyL PET/MRI (n = 105), were included in this retrospective analysis of two prospective clinical trials. Radiomic features were extracted from the segmented volumes following the image biomarker standardization initiative (IBSI) guidelines. Histopathology obtained from systematic and targeted biopsies of the PET/MRI-detected lesions was the reference standard. Histopathology patterns were dichotomized as ISUP GG 1-2 vs. ISUP GG ≥ 3 categories. Different single-modality models were defined for feature extraction, including PET- and MRI-derived radiomic features. The clinical model included age, PSA, and lesions' PROMISE classification. Single models, as well as different combinations of them, were generated to calculate their performances. A cross-validation approach was used to evaluate the internal validity of the models.

RESULTS

All radiomic models outperformed the clinical models. The best model for grade group prediction was the combination of PET + ADC + T2w radiomic features, showing sensitivity, specificity, accuracy, and AUC of 0.85, 0.83, 0.84, and 0.85, respectively. The MRI-derived (ADC + T2w) features showed sensitivity, specificity, accuracy, and AUC of 0.88, 0.78, 0.83, and 0.84, respectively. PET-derived features showed 0.83, 0.68, 0.76, and 0.79, respectively. The baseline clinical model showed 0.73, 0.44, 0.60, and 0.58, respectively. The addition of the clinical model to the best radiomic model did not improve the diagnostic performance. The performances of MRI and PET/MRI radiomic models as per the cross-validation scheme yielded an accuracy of 0.80 (AUC = 0.79), whereas clinical models presented an accuracy of 0.60 (AUC = 0.60).

CONCLUSION

The combined [18F]-DCFPyL PET/MRI radiomic model was the best-performing model and outperformed the clinical model for pathological grade group prediction, indicating a complementary value of the hybrid PET/MRI model for non-invasive risk stratification of PCa. Further prospective studies are required to confirm the reproducibility and clinical utility of this approach.

A Systematic Review of the Variability in Performing and Reporting Intraprostatic Prostate-specific Membrane Antigen Positron Emission Tomography in Primary Staging Studies

Context

Prostate cancer (PCa) remains one of the leading causes of cancer-related deaths in men worldwide. Men at risk are typically offered multiparametric magnetic resonance imaging and, if suspicious, a targeted biopsy. However, false-negative rates of magnetic resonance imaging are consistently 18%; therefore, there is growing interest in improving the diagnostic performance of imaging through novel technologies. Prostate-specific membrane antigen (PSMA) positron emission tomography (PET) is being utilised for PCa staging and, more recently, for intraprostatic tumour localisation. However, significant variability has been observed in how PSMA PET is performed and reported.

Objective

In this review, we aim to evaluate how pervasive this variability is in trials investigating the performance of PSMA PET in primary PCa workup.

Evidence acquisition

Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, we performed an optimal search in five different databases. After removing duplicates, 65 studies were included in our review.

Evidence synthesis

Studies dated back as early as 2016, with numerous different source countries. There was variation in the reference standard for PSMA PET, with some using biopsy specimens or surgical specimens, and in some cases, a combination of the two. Similar inconsistencies were noted when studies selected histological definitions of clinically significant PCa, while some omitted their definition altogether. The most significant variations in performing PSMA PET were the radiotracer type, dose, acquisition time after injection, and the PET camera being utilised. Substantial variation in the reporting of PSMA PET was noted, with no consistency in defining what constitutes a positive intraprostatic lesion. Across 65 studies, four different definitions were used.

Conclusions

This systematic review has highlighted considerable variation in obtaining and performing a PSMA PET study in the context of primary PCa diagnosis. Given the discrepancy in how PSMA PET was performed and reported, it questions the homogony of studies from centre to centre. Standardisation of PSMA PET is required for this to become a consistently useful and reproducible modality in the diagnosis of PCa.

Patient summary

Prostate-specific membrane antigen (PSMA) positron emission tomography (PET) is being utilised for staging and localisation of prostate cancer (PCa); however, there is significant variability in performing and reporting PSMA PET. Standardisation of PSMA PET is required for results to be consistently useful and reproducible for the diagnosis of PCa.

Dual-Tracer PET-MRI-Derived Imaging Biomarkers for Prediction of Clinically Significant Prostate Cancer

PURPOSE

To investigate if imaging biomarkers derived from 3-Tesla dual-tracer [(18)F]fluoromethylcholine (FMC) and [⁶⁸Ga]Ga-PSMA^HBED-CC conjugate 11 (PSMA)-positron emission tomography can adequately predict clinically significant prostate cancer (csPC).

METHODS

We assessed 77 biopsy-proven PC patients who underwent 3T dual-tracer PET/mpMRI followed by radical prostatectomy (RP) between 2014 and 2017. We performed a retrospective lesion-based analysis of all cancer foci and compared it to whole-mount histopathology of the RP specimen. The primary aim was to investigate the pretherapeutic role of the imaging biomarkers FMC- and PSMA-maximum standardized uptake values (SUVmax) for the prediction of csPC and to compare it to the mpMRI-methods and PI-RADS score.

RESULTS

Overall, we identified 104 cancer foci, 69 were clinically significant (66.3%) and 35 were clinically insignificant (33.7%). We found that the combined FMC+PSMA SUVmax were the only significant parameters (p < 0.001 and p = 0.049) for the prediction of csPC. ROC analysis showed an AUC for the prediction of csPC of 0.695 for PI-RADS scoring (95% CI 0.591 to 0.786), 0.792 for FMC SUVmax (95% CI 0.696 to 0.869), 0.852 for FMC+PSMA SUVmax (95% CI 0.764 to 0.917), and 0.852 for the multivariable CHAID model (95% CI 0.763 to 0.916). Comparing the AUCs, we found that FMC+PSMA SUVmax and the multivariable model were significantly more accurate for the prediction of csPC compared to PI-RADS scoring (p = 0.0123, p = 0.0253, respectively).

CONCLUSIONS

Combined FMC+PSMA SUVmax seems to be a reliable parameter for the prediction of csPC and might overcome the limitations of PI-RADS scoring. Further prospective studies are necessary to confirm these promising preliminary results.

The diagnostic performance of 18F-DCFPyL PET in patients with suspected prostate cancer: A systemic review and meta-analysis

Introduction

Our meta-analysis aimed to evaluate the diagnostic value of ¹⁸F-DCFPyL prostate-specific membrane antigen (PSMA) PET in patients with suspected prostate cancer.

Methods

We searched for articles that evaluate the diagnostic value of ¹⁸F-DCFPyL PSMA PET in patients with suspected prostate cancer in PubMed, Embase, Cochrane Library, and Web of Science until 1 August 2022. Using the QUADAS-2 instrument, two researchers independently assessed the effectiveness of the studies that were included. The four-grid table data were analyzed by Meta-disc1.4 and Stata 16.0 software. The heterogeneity of each study was tested.

Results

A total of five studies with 258 patients were included, and the pooled sensitivity and specificity of ¹⁸F-DCFPyL PSMA PET for primary prostate cancer were 0.92 (95% confidence interval (CI): 0.85-0.96) and 0.59 (95% CI: 0.08-0.96), respectively. ¹⁸F-DCFPyL PSMA PET was successful in detecting primary prostate cancer, with an area under the curve (AUC) of 0.92 (95% CI: 0.89-0.94).

Conclusions

¹⁸F-DCFPyL PSMA PET has a strong predictive value for primary prostate cancer and is an effective method for the non-invasive diagnosis of prostate cancer. More prospective articles were needed.

Diagnostic Performance of Prostate-specific Membrane Antigen Positron Emission Tomography-targeted biopsy for Detection of Clinically Significant Prostate Cancer: A Systematic Review and Meta-analysis

CONTEXT

Prostate-specific membrane antigen positron emission tomography (PSMA-PET) has gained acceptance as a staging tool for prostate cancer (PCa). Recent reports suggest an association between PSMA PET and detection of clinically significant PCa (csPCa) on prostate biopsy.

OBJECTIVE

To assess the diagnostic accuracy of PSMA PET-targeted biopsy (PSMA-PET-TB) for csPCa detection.

EVIDENCE ACQUISITION

We searched PubMed, Web of Science, and Scopus in December 2021 to identify studies assessing the accuracy of PSMA-PET-TB for csPCa detection. A diagnostic meta-analysis was performed to calculate pooled sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of PSMA-PET-TB alone and in combination with magnetic resonance imaging (MRI)-TB for detecting csPCa.

EVIDENCE SYNTHESIS

Overall, five prospective studies involving 497 patients were eligible for this meta-analysis. For csPCa detection, PSMA-PET-TB had pooled sensitivity, specificity, PPV, and NPV of 0.89 (95% confidence interval [CI] 0.85-0.93), 0.56 (95% CI 0.29-0.80), 0.69 (95% CI 0.58-0.79), and 0.78 (95% CI 0.50-0.93), respectively. Among the three studies assessing the PSMA-PET + MRI-TB strategy, the pooled sensitivity, specificity, PPV, and NPV for csPCa detection were 0.91 (95% CI 0.77-0.97), 0.64 (95% CI 0.40-0.82), 0.75 (95% CI 0.56-0.87), and 0.85 (95% CI 0.62-0.95), respectively. For lesions with a Prostate Imaging-Reporting and Data System (PI-RADS) score of 3, the sensitivity, specificity, PPV, and NPV were 0.69, 0.73, 0.48, and 0.86, respectively.

CONCLUSIONS

PSMA-PET-TB appears to have favorable diagnostic accuracy for csPCa detection and combination with MRI seems to improve this. According to our meta-analysis, PSMA-PET has promising clinical application for detection of csPCa, namely in the case of PI-RADS 3 lesions. Further prospective studies are needed to explore the true clinical utility of a PSMA-PET-based diagnostic pathway.

PATIENT SUMMARY

Prostate-specific membrane antigen positron emission tomography (PSMA-PET) is a promising imaging method for detecting clinically significant prostate cancer and seems to have additional value to magnetic resonance imaging (MRI) for detection.

Piflufolastat F 18: Diagnostic First Approval

Piflufolastat F 18 (PYLARIFY^®) is an ¹⁸F-labelled diagnostic imaging agent that has been developed by Progenics Pharmaceuticals Inc., a Lantheus company, for positron emission tomography (PET) that targets prostate-specific membrane antigen (PSMA). Piflufolastat F 18 was approved in the USA on 27 May 2021 for PET of PSMA positive lesions in men with prostate cancer with suspected metastasis who are candidates for initial definitive therapy or with suspected recurrence based on elevated serum prostate specific antigen (PSA) level. This article summarizes the milestones in the development of piflufolastat F 18 leading to this approval as a radioactive diagnostic agent in prostate cancer.