Effect of 18F-DCFPyL PET/CT on the Management of Patients with Recurrent Prostate Cancer: Results of a Prospective Multicenter Registry Trial

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.

Controversies in prostate cancer management: Consensus recommendations from experts in northern Spain

In recent years, various aspects of prostate cancer (PC) management have undergone significant changes, including the implementation of therapeutic strategies such as the use of new hormonal agents like abiraterone, apalutamide, enzalutamide or darolutamide and the incorporation of next generation imaging techniques (NGI). However, the evidence regarding the role of NGI and the therapeutic decision-making based on their findings is not solid. Following the methodology of the Advanced Prostate Cancer Consensus Conference (APCCC), a multidisciplinary expert consensus was developed to address controversial questions concerning the use of NGI and clinical management in four priority scenarios: localized PC, PC after radical prostatectomy, PC after radiotherapy with curative intent, and metastatic hormone-sensitive PC. This consensus represents the opinions of medical oncology, radiation oncology and urology physicians and provides useful recommendations for clinical practice.

Prostate-specific Membrane Antigen: Diagnostics

Since its clinical introduction in May 2011, prostate-specific membrane antigen (PSMA)-PET/computed tomography has quickly gained worldwide recognition as a significant breakthrough in prostate cancer diagnostics. In the meantime, several new PSMA radioligands for PET imaging have been introduced into routine clinical practice. This article aims to introduce the most commonly used tracers and their key areas of application.

Prostate Magnetic Resonance Imaging Using the Prostate Imaging for Recurrence Reporting (PI-RR) Scoring System to Detect Recurrent Prostate Cancer: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVE

Prostate Imaging for Recurrence Reporting (PI-RR) was introduced in 2021 to standardize the interpretation and reporting of multiparametric magnetic resonance imaging (MRI) for prostate cancer following whole-gland treatment. The system scores image on a scale from 1 to 5 and has shown promising results in single-center studies. The aim of our systematic review and meta-analysis was to assess the diagnostic performance of the PI-RR system in predicting the likelihood of local recurrence after whole-gland treatment.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for diagnostic test accuracy were followed. Relevant databases were searched up to December 2023. Primary studies met the eligibility criteria if they reported MRI diagnostic performance in prostate cancer recurrence using PI-RR. Diagnostic performance for MRI was assessed using two different cutoff points (≥3 or ≥4 for positivity according to the PI-RR system). A meta-analysis with a random-effects model was used to estimate pooled sensitivity and specificity values.

KEY FINDINGS AND LIMITATIONS

Sixteen articles were identified for full-text reading, of which six were considered eligible, involving a total of 467 patients. Using a cutoff of PI-RR ≥3 (4 studies) for recurrent disease, the sensitivity was 77.8% (95% confidence interval [CI] 69.9-84.1%) and the specificity was 80.2% (95% CI 58.2-92.2%). Using a cutoff of PI-RR ≥4 (4 studies), the sensitivity was 61.9% (95% CI 35.6-82.7%) and the specificity was 86.6% (95% CI 75.1-93.3%). Overall, the inter-rater agreement varied from fair to excellent.

CONCLUSIONS AND CLINICAL IMPLICATIONS

PI-RR is accurate in detecting local recurrence after whole-gland treatment for prostate cancer and shows fair-to-good to excellent inter-reader agreement. Overall, a PI-RR cutoff of ≥3 showed high sensitivity and specificity.

PATIENT SUMMARY

We reviewed studies that reported on how good MRI scans using a scoring system called PI-RR were in detecting recurrence of prostate cancer. We found that this system shows good performance, with fair to excellent agreement between different radiologists.

Effect of 18F-DCFPyL PET on changes in management of patients with prostate cancer: a systematic review and meta-analysis

Purpose

Prostate-specific membrane antigen (PSMA)-targeted imaging has gained increasing interest in its application in prostate cancer lesion detection. Compared with 68Galium (68Ga), 18Fluoride (18F)-labeled imaging agent has easier syntheses, lower price, and a longer half-time. 2-(3-{1-Carboxy-5-[(6-[18F]fluoro-pyridine-3-carbonyl)-amino]-pentyl}-ureido)-pentanedioic acid positron emission tomography (18F-DCFPyL PET) has been recently approved by the U.S. Food and Drug Administration. Several studies have proven its superiority to conventional imaging techniques in detecting prostate cancer lesions. However, the impact of 18F-DCFPyL PET on the management of patients with prostate cancer is not well established. Thus, we performed a systematic review and meta-analysis of available data to evaluate the impact of 18F-DCFPyL PET on the management of patients with prostate cancer.

Methods

The PubMed, Embase, Scopus, and Cochrane databases were searched up to April 2024. Studies that reported the proportion of changes in management after 18F-DCFPyL PET was performed in patients with prostate cancer were included. The Grading of Recommendations Assessment, Development, and Evaluation system was used for the quality evaluation of the included studies. The proportion of changes in management was pooled using a random effects model. Meta-regression analyses were performed to assess the potential correlation between the PET positivity and management changes.

Results

Fourteen studies (3,078 patients with prostate cancer) were included in our review and analysis. The pooled percentage of management changes was 43.5% (95% confidence interval [CI]: 33-54%). In patients with biochemical recurrent and for primary staging, the pooled percentage was 50% (95% CI: 39-60%) and 22% (95% CI: 15-29%), respectively. In the meta-regression analyses, PET positivity was detected as a significant predictor of management change (p = 0.0023).

Conclusion

18F-DCFPyL PET significantly affects the management of patients with prostate cancer. Higher PET positivity rate significantly correlated with a higher proportion of management changes in patients with prostate cancer. However, more studies are still needed to confirm the important role of 18F-DCFPyL PET in the management of prostate cancer.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/#myprospero, CRD42022339178.

Mesorectal nodal metastasis with seminal vesicle invasion in biochemically recurrent prostate cancer

OBJECTIVES

To determine the prevalence and predictors of mesorectal lymph node (MLN) metastases on prostate-specific membrane antigen (PSMA)-based positron emission tomography/computed tomography (PET/CT) in patients with biochemically recurrent prostate cancer (PCa) following radical therapy.

MATERIALS AND METHODS

This was a cross-sectional analysis of all PCa patients with biochemical failure following radical prostatectomy or radiotherapy who underwent an 18 F-DCFPyL-PSMA-PET/CT at the Princess Margaret Cancer Centre between December 2018 and February 2021. Lesions with PSMA scores ≥2 were considered positive for PCa involvement (PROMISE classification). Predictors of MLN metastasis were evaluated using univariable and multivariable logistic regression analyses.

RESULTS

Our cohort consisted of 686 patients. The primary treatment method was radical prostatectomy and radiotherapy in 528 (77.0%) and 158 patients (23.0%), respectively. The median serum PSA level was 1.15 ng/mL. Overall, 384 patients (56.0%) had a positive scan. Seventy-eight patients (11.3%) had MLN metastasis, with 48/78 (61.5%) having MLN involvement as the only site of metastasis. On multivariable analysis, presence of pT3b disease (odds ratio 4.31, 95% confidence interval 1.44-14.2; P = 0.011) was significantly associated with increased odds of MLN metastasis, whereas surgical factors (radical prostatectomy vs radiotherapy; performance/extent of pelvic nodal dissection), surgical margin positivity, and Gleason Grade were not.

CONCLUSIONS

In this study, 11.3% of PCa patients with biochemical failure had MLN metastasis on 18 F-DCFPyL-PET/CT. pT3b disease was associated with 4.31-fold significantly increased odds of MLN metastasis. These findings suggest alternate drainage routes for PCa cells, either via alternate lymphatic drainage from the seminal vesicles themselves or secondary to direct extension from posteriorly located tumours invading the seminal vesicles.

Association of PSMA PET-derived Parameters and Outcomes of Patients Treated for Oligorecurrent Prostate Cancer

Background Prostate-specific membrane antigen (PSMA) PET is useful in the early detection of oligorecurrent prostate cancer (PCa), but whether PSMA PET parameters can be used to identify patients who would benefit from metastasis-directed therapy (MDT) with radiation or surgery remains uncertain. Purpose To assess the association of PSMA PET parameters with outcomes of patients with oligorecurrent PCa after MDT. Materials and Methods In this retrospective analysis of a single-center phase II trial that enrolled patients with biochemical recurrence of PCa after maximal local therapy and with no evidence of disease at conventional imaging, patients underwent PSMA PET (between May 2017 and November 2021), and unveiled recurrences were treated with MDT. Maximum standardized uptake value (SUVmax) and mean standardized uptake value (SUVmean) and PSMA tumor volume derived using thresholds of 2.5 (SUVmean2.5) and 41% (SUVmean41%), respectively, were recorded for sites of recurrence on PSMA PET scans, and a molecular imaging PSMA score was assigned. These parameters were also corrected for smooth filter and partial volume effects, and the PSMA score was reassigned. Cox proportional hazards models were used to evaluate the relationship between PSMA PET parameters and outcomes. Results A total of 74 men (mean age, 68.3 years ± 6.6 [SD]) with biochemical recurrence of PCa were included. PSMA PET revealed 145 lesions in the entire cohort, of which 125 (86%) were metastatic lymph nodes. Application of the correction factor changed the PSMA score in 88 of 145 lesions (61%). Mean SUVmax, SUVmean2.5, and SUVmean41% were associated with lower risk of biochemical progression (hazard ratio [HR] range, 0.77-0.95; 95% CI: 0.61, 1.00; P = .03 to P = .04). For corrected parameters, mean SUVmax, mean SUVmean2.5, mean SUVmean41%, mean PSMA score, maximum SUVmean2.5, maximum SUVmean41%, and maximum PSMA score were associated with a lower risk of biochemical progression (HR, 0.61-0.98; 95% CI: 0.39, 1.00; P = .01 to P = .04). Conclusion Measured and corrected PSMA PET parameters were associated with biochemical progression in men with oligorecurrent PCa treated with MDT. Clinical trial registration no. NCT03160794 © RSNA, 2023 See also the editorial by Civelek in this issue.

Lymphotropic Pattern of Prostate-specific Membrane Antigen-detected Metastases Among Biochemically Recurrent Radical Prostatectomy Patients with Cribriform Disease

BACKGROUND

Cribriform morphology portends worse oncologic outcomes, and has unique cellular intrinsic pathway alterations and tumor microenvironments that may impact metastatic spread patterns.

OBJECTIVE

To determine whether the presence of cribriform morphology in prostatectomy specimens of patients with biochemical recurrence after radical prostatectomy (RP) is associated with the presence of metastasis on prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) and a distinct pattern of spread.

DESIGN, SETTING, AND PARTICIPANTS

A cross-sectional analysis was conducted of all prostate cancer patients with biochemical recurrence after RP undergoing 18F-DCFPyL-PET/CT between December 2018 and February 2021 at the Princess Margaret Cancer Centre.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Outcomes were presence of any metastasis in the overall cohort and lymphatic versus bone/visceral metastases among patients with metastatic disease. The associations between the presence of intraductal (IDC) and/or invasive cribriform (ICC) carcinoma on the RP specimen and study outcomes were evaluated using logistic regression analyses.

RESULTS AND LIMITATIONS

The cohort included 176 patients. IDC and ICC were observed in 77 (43.8%) and 80 (45.5%) RP specimens, respectively. The median time from RP to PSMA-PET/CT was 5.0 yr. The median serum prostate-specific antigen level at PSMA-PET/CT was 1.12 ng/ml. Overall, metastasis was observed in 77 patients, of whom 58 were had lymphatic-only metastasis. On a multivariable analysis, presence of IDC on RP was associated with increased odds of overall metastasis (odds ratio [OR]: 2.17; 95% confidence interval [CI]: 1.07-4.45; p = 0.033). Presence of ICC on RP was associated with significantly increased odds of lymphatic versus bone/visceral metastases (OR: 3.13; 95% CI: 1.09-21.7; p = 0.004).

CONCLUSIONS

Presence of cribriform morphology on RP specimens of patients with biochemical failure after RP is associated with increased odds of PSMA-PET/CT-detected metastases with a lymphatic predominant pattern of spread. These findings have implications for the design and evaluation of post-RP salvage therapies.

PATIENT SUMMARY

We found that microscopic cribriform appearance correlates with disease spread on imaging in prostate cancer patients with recurrence and has a predilection for spread to lymph nodes, as opposed to bone or visceral organs.

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.

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.

Eligibility for 177Lu-PSMA Therapy Depends on the Choice of Companion Diagnostic Tracer: A Comparison of 68Ga-PSMA-11 and 99mTc-MIP-1404 in Metastatic Castration-Resistant Prostate Cancer

¹⁷⁷Lu-prostate-specific membrane antigen-617 (¹⁷⁷Lu-PSMA-617) is an effective therapy for metastatic castration-resistant prostate cancer (mCRPC), with evidence of improved survival over standard care. The VISION trial inclusion criteria required a metastatic lesion-to-liver ratio of greater than 1 on ⁶⁸Ga-PSMA-11 PET scans. We aimed to determine whether an equivalent ratio is suitable for a SPECT tracer, ^99mTc-MIP-1404, and to compare lesion and lesion-to-normal-organ ratios between the 2 radiotracers. Methods: Two cohorts of patients with mCRPC matched for age, prostate-specific antigen level, and total Gleason score, with either ^99mTc-MIP-1404 SPECT/CT (n = 25) or ⁶⁸Ga-PSMA-11 PET/CT (n = 25) scans, were included for analysis. Up to 3 lesions in each site (prostate/prostate bed, lymph nodes, bone and soft-tissue metastases) as well as normal liver, parotid gland, spleen, and mediastinal blood-pool SUV_max were measured. Results: ^99mTc-MIP-1404 SPECT lesion SUV_max was not significantly different from ⁶⁸Ga-PSMA-11 PET (median, 18.2 vs. 17.3; P = 0.93). However, ^99mTc-MIP-1404 liver SUV_max was higher (median, 8.5 vs. 5.8; P = 0.002) and lesion-to-liver ratios were lower (median, 2.7 vs. 3.5; P = 0.009). There was no significant difference in parotid gland or splenic SUV_max or lesion-to-parotid gland ratios between the 2 tracers although there was a small difference in lesion-to-spleen ratios (P = 0.034). Conclusion: There are differences in biodistribution and, in particular, liver activity, between ⁶⁸Ga-PSMA-11 and ^99mTc-MIP-1404. Therefore, if ^99mTc-MIP-1404 is used to assess eligibility for ¹⁷⁷Lu-PSMA-617 therapy, a lower adjusted lesion-to-liver ratio should be used.

Standardized classification schemes in reporting oncologic PET/CT

The imaging report is essential for the communication between physicians in patient care. The information it contains must be clear, concise with evidence-based conclusions and sufficient to support clinical decision-making. In recent years, several classification schemes and/or reporting guidelines for PET have been introduced. In this manuscript, we will review the classifications most frequently used in oncology for interpreting and reporting 18F-FDG PET imaging in lymphoma, multiple myeloma, melanoma and head and neck cancers, PSMA-ligand PET imaging for prostate cancer, and 68Ga-DOTA-peptide PET in neuroendocrine tumors (NET).

Oligometastases: Emerging Evidence

The hypothesis that ablative therapies (such as surgery or radiation) can be used to cure patients with a limited number of metastases was influential in changing practice. Early assertions of efficacy were based on observational studies, often without control groups, showing better-than-expected outcomes. However, in the past decade, new evidence from randomized trials has emerged, which in some cases have affirmed old hypotheses, but in other cases have raised new questions. In this review, we discuss the challenges in defining oligometastatic disease, summarize the randomized evidence evaluating metastasis-directed therapy in patients with oligometastatic disease, provide context for the difficulty in generating randomized evidence, and examine ongoing phase III studies.

Use of "Diagnostic Yield" in Imaging Research Reports: Results from Articles Published in Two General Radiology Journals

OBJECTIVE

"Diagnostic yield," also referred to as the detection rate, is a parameter positioned between diagnostic accuracy and diagnosis-related patient outcomes in research studies that assess diagnostic tests. Unfamiliarity with the term may lead to incorrect usage and delivery of information. Herein, we evaluate the level of proper use of the term "diagnostic yield" and its related parameters in articles published in Radiology and Korean Journal of Radiology (KJR).

MATERIALS AND METHODS

Potentially relevant articles published since 2012 in these journals were identified using MEDLINE and PubMed Central databases. The initial search yielded 239 articles. We evaluated whether the correct definition and study setting of "diagnostic yield" or "detection rate" were used and whether the articles also reported companion parameters for false-positive results. We calculated the proportion of articles that correctly used these parameters and evaluated whether the proportion increased with time (2012-2016 vs. 2017-2022).

RESULTS

Among 39 eligible articles (19 from Radiology and 20 from KJR), 17 (43.6%; 11 from Radiology and 6 from KJR) correctly defined "diagnostic yield" or "detection rate." The remaining 22 articles used "diagnostic yield" or "detection rate" with incorrect meanings such as "diagnostic performance" or "sensitivity." The proportion of correctly used diagnostic terms was higher in the studies published in Radiology than in those published in KJR (57.9% vs. 30.0%). The proportion improved with time in Radiology (33.3% vs. 80.0%), whereas no improvement was observed in KJR over time (33.3% vs. 27.3%). The proportion of studies reporting companion parameters was similar between journals (72.7% vs. 66.7%), and no considerable improvement was observed over time.

CONCLUSION

Overall, a minority of articles accurately used "diagnostic yield" or "detection rate." Incorrect usage of the terms was more frequent without improvement over time in KJR than in Radiology. Therefore, improvements are required in the use and reporting of these parameters.

A Risk Model for Patients with PSA-Only Recurrence (Biochemical Recurrence) Based on PSA and PSMA PET/CT: An Individual Patient Data Meta-Analysis

An individual patient meta-analysis followed 1216 patients with PSA-only recurrence (biochemical recurrence, BCR) restaged with [68Ga]Ga-PSMA-11 PET/CT before the salvage treatment for median 3.5 years and analyzed the overall survival (OS). A new risk model included a good risk group with a prescan PSA < 0.5 ng/mL (26%), an intermediate risk group with a prescan PSA > 0.5 ng/mL and a PSMA PET/CT with 1 to 5 positive sites (65%), and a poor risk group with a prescan PSA > 0.5 ng/mL and a PSA PET/CT with > 5 positive sites (9%) (p < 0.0001, log rank test). The poor risk group had a five-year OS > 60%. Adding a BCR risk score by the European Association of Urology did not significantly improve the prediction of OS (p = 0.64). In conclusion, the restaging PSMA PET/CT markedly predicted the 5-year OS. The new risk model for patients with PSA-only relapse requires a restaging PSMA PET/CT for patients with a prescan PSA > 0.5 ng/mL and has a potential use in new trials aiming to improve the outcome for patients with PSA-only recurrence who have polysites prostate cancer detected on PSMA PET/CT.

18F-DCFPyL PET/CT in advanced high-grade epithelial ovarian cancer: A prospective pilot study

Objectives

Glutamate carboxypeptidase-II (GCP-II), a zinc metalloenzyme that resides in cell membrane, has been reported as overexpressed in the neovasculature of ovarian cancers. The study objective was to determine whether GCP-II targeted imaging with ¹⁸F-DCFPyL PET/CT can detect disease sites in women with advanced high-grade serous ovarian cancer (HGSOC).

Materials and methods

Twenty treatment-naïve women with advanced HGSOC were recruited (median age 60 years). Prior to commencing therapy (primary cytoreductive surgery [n=9] or neoadjuvant chemotherapy [n=11]), subjects underwent routine staging with contrast-enhanced abdominopelvic CT (=CT), followed by ¹⁸F-DCFPyL PET/CT (=PET). CT and PET were reported independently using a standardized reporting template assessing 25 sites. The performance of PET was compared to CT in all subjects and to surgery and surgical histopathology in 9 patients who underwent primary cytoreductive surgery.

Results

Of the 25 sites assessed in 20 patients, CT detected disease in 292/500 (58.4%) locations and PET detected disease in 171/500 (34.2%). Compared to CT the sensitivity (95% CI) of PET to detect disease in the upper abdomen, the gastrointestinal tract or the peritoneum was 0.29 (0.20,0.40), 0.21 (0.11,0.33) and 0.74 (0.64,0.82), respectively. In the surgical cohort, 220 sites in 9 patients were evaluated. The sensitivity and specificity of CT and PET were 0.85 versus 0.54 (p<0.001) and 0.73 versus 0.93 (p<0.001), respectively.

Conclusion

Although ¹⁸F-DCFPyL has higher specificity than CT in detecting advanced HGSOC tumor sites, it detects less disease sites than CT, especially in the upper abdomen and along the gastrointestinal tract, likely limiting its clinical utility.

Clinical trial registration

ClinicalTrials.gov, NCT03811899.

PSMA theragnostics for metastatic castration resistant prostate cancer

•

PSMA targeted theragnostic agents have shown tremendous potential in detecting and treating metastatic prostate cancer.

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The PSMA small molecular inhibitor-based imaging agents achieve extraordinary tumor to background ratios and the PSMA small molecule therapeutic agents have shown impressive therapeutic index in mCRPC.

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The development and optimization of PSMA theragnostic agents provides invaluable information that may help guide development of future theragnostics for other solid tumors.

There has been tremendous growth in the development of theragnostics for personalized cancer diagnosis and treatment over the past two decades. In prostate cancer, the new generation of prostate specific membrane antigen (PSMA) small molecular inhibitor-based imaging agents achieve extraordinary tumor to background ratios and allow their therapeutic counterparts to deliver effective tumor doses while minimizing normal tissue toxicity. The PSMA targeted small molecule positron emission tomography (PET) agents ¹⁸F-DCFPyL (2-(3-{1-carboxy-5-((6-(18)F-fluoro-pyridine-3-carbonyl)-amino)-pentyl}-ureido)-pentanedioic acid) and Gallium-68 (⁶⁸Ga)-PSMA-11 have been approved by the United States Food and Drug Administration (FDA) for newly diagnosed high risk prostate cancer patients and for patients with biochemical recurrence. More recently, the Phase III VISION trial showed that Lutetium-177 (¹⁷⁷Lu)-PSMA-617 treatment increases progression-free survival and overall survival in patients with heavily pre-treated advanced PSMA-positive metastatic castration-resistant prostate cancer (mCRPC). Here, we review the PSMA targeted theragnostic pairs under clinical investigation for detection and treatment of metastatic prostate cancer.

PSMA PET/CT guided intensification of therapy in patients at risk of advanced prostate cancer (PATRON): a pragmatic phase III randomized controlled trial

BACKGROUND

Positron emission tomography targeting the prostate specific membrane antigen (PSMA PET/CT) has demonstrated unparalleled performance as a staging examination for prostate cancer resulting in substantial changes in management. However, the impact of altered management on patient outcomes is largely unknown. This study aims to assess the impact of intensified radiotherapy or surgery guided by PSMA PET/CT in patients at risk of advanced prostate cancer.

METHODS

This pan-Canadian phase III randomized controlled trial will enroll 776 men with either untreated high risk prostate cancer (CAPRA score 6-10 or stage cN1) or biochemically recurrent prostate cancer post radical prostatectomy (PSA > 0.1 ng/mL). Patients will be randomized 1:1 to either receive conventional imaging or conventional plus PSMA PET imaging, with intensification of radiotherapy or surgery to newly identified disease sites. The primary endpoint is failure free survival at 5 years. Secondary endpoints include rates of adverse events, time to next-line therapy, as well as impact on health-related quality of life and cost effectiveness as measured by incremental cost per Quality Adjusted Life Years gained.

DISCUSSION

This study will help create level 1 evidence needed to demonstrate whether or not intensification of radiotherapy or surgery based on PSMA PET findings improves outcomes of patients at risk of advanced prostate cancer in a manner that is cost-effective.

TRIAL REGISTRATION

This trial was prospectively registered in ClinicalTrials.gov as NCT04557501 on September 21, 2020.