A Comparison of Globally Applied Prognostic Risk Groups and the Prevalence of Metastatic Disease on Prostate-specific Membrane Antigen Positron Emission Tomography in Patients with Newly Diagnosed Prostate Cancer.

BACKGROUND: Various risk classification systems (RCSs) are used globally to stratify newly diagnosed patients with prostate cancer (PCa) into prognostic groups. OBJECTIVE: To compare the predictive value of different prognostic subgroups (low-, intermediate-, and high-risk disease) within the RCSs for detecting metastatic disease on prostate-specific membrane antigen (PSMA) positron emission tomography (PET)/computed tomography (CT) for primary staging, and to assess whether further subdivision of subgroups would be beneficial. DESIGN, SETTING, AND PARTICIPANTS: Patients with newly diagnosed PCa, in whom PSMA-PET/CT was performed between 2017 and 2022, were studied retrospectively. Patients were stratified into risk groups based on four RCSs: European Association of Urology, National Comprehensive Cancer Network (NCCN), Cambridge Prognostic Group (CPG), and Cancer of the Prostate Risk Assessment. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The prevalence of metastatic disease on PSMA-PET/CT was compared among the subgroups within the four RCSs. RESULTS AND LIMITATIONS: In total, 2630 men with newly diagnosed PCa were studied. Any metastatic disease was observed in 35% (931/2630) of patients. Among patients classified as having intermediate- and high-risk disease, the prevalence of metastases ranged from approximately 12% to 46%. Two RCSs further subdivided these groups. According to the NCCN, metastatic disease was observed in 5.8%, 13%, 22%, and 62% for favorable intermediate-, unfavorable intermediate-, high-, and very-high-risk PCa, respectively. Regarding the CPG, these values were 6.9%, 13%, 21%, and 60% for the corresponding risk groups. CONCLUSIONS: This study underlines the importance of nuanced risk stratification, recommending the further subdivision of intermediate- and high-risk disease given the notable variation in the prevalence of metastatic disease. PSMA-PET/CT for primary staging should be reserved for patients with unfavorable intermediate- or higher-risk disease. PATIENT SUMMARY: The use of various risk classification systems in patients with prostate cancer helps identify those at a higher risk of having metastatic disease on prostate-specific membrane antigen positron emission tomography/computed tomography for primary staging.

The Probability of Metastases Within Different Prostate-specific Antigen Ranges Using Prostate-specific Membrane Antigen Positron Emission Tomography in Patients with Newly Diagnosed Prostate Cancer.

Background and objectives: The association between prostate-specific antigen (PSA) level and probability of metastatic disease on prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) has not yet been established in patients with newly diagnosed prostate cancer (PCa). Our objective was to assess the probability of metastatic disease within different PSA ranges using PSMA PET/CT for initial staging of PCa, and to identify both the anatomical distribution and the predictors of metastases on PSMA PET/CT. Methods: In total, 2193 patients with newly diagnosed PCa were retrospectively studied. PSMA PET/CT was performed for staging purposes between January 2017 and May 2022. The proportion of patients with PSMA-avid metastases, stratified by PSA level, was studied. A vast majority of patients in whom at least one high-risk prognostic factor was present underwent PSMA PET/CT. A multivariable logistic regression analysis was performed to identify the predictors of metastases on PSMA PET/CT using clinical, biochemical, radiological, and pathological variables. Key findings and limitations: The median PSA level at PSMA PET/CT was 14.1 ng/ml. Any metastatic disease (miN1-M1a-c) was observed in 34.7% (763/2193) of all patients and distant metastases (miM1a-c) in 25.4% (557/2193) of patients. The presence of any metastatic disease increased with PSA levels, being 15.4% in men with PSA levels <10 ng/ml and 87.5% in men with PSA levels >100 ng/ml. The multivariable logistic regression analysis found significant associations between the presence of any metastatic disease and PSA subgroups, clinical tumor stage ≥T2, grade group >3, and radiological tumor stage ≥T3b. Conclusions and clinical implications: This is the first large epidemiological study in patients with PCa demonstrating the association between PSA subgroups and metastatic disease on modern imaging PSMA PET/CT. Data from this study can be used to counsel patients on the probability of metastatic disease at the time of PSA screening and to provide guidance on existing guidelines. Patient summary: The prostate-specific antigen level could be used to assess the risk of metastases on prostate-specific membrane antigen positron (PSMA) emission tomography/computed tomography (PET/CT). This knowledge is valuable for selecting patients who will benefit most from metastatic screening with PSMA PET/CT.

Optimization and validation of 18F-DCFPyL PET radiomics-based machine learning models in intermediate- to high-risk primary prostate cancer.

INTRODUCTION: Radiomics extracted from prostate-specific membrane antigen (PSMA)-PET modeled with machine learning (ML) may be used for prediction of disease risk. However, validation of previously proposed approaches is lacking. We aimed to optimize and validate ML models based on 18F-DCFPyL-PET radiomics for the prediction of lymph-node involvement (LNI), extracapsular extension (ECE), and postoperative Gleason score (GS) in primary prostate cancer (PCa) patients. METHODS: Patients with intermediate- to high-risk PCa who underwent 18F-DCFPyL-PET/CT before radical prostatectomy with pelvic lymph-node dissection were evaluated. The training dataset included 72 patients, the internal validation dataset 24 patients, and the external validation dataset 27 patients. PSMA-avid intra-prostatic lesions were delineated semi-automatically on PET and 480 radiomics features were extracted. Conventional PET-metrics were derived for comparative analysis. Segmentation, preprocessing, and ML methods were optimized in repeated 5-fold cross-validation (CV) on the training dataset. The trained models were tested on the combined validation dataset. Combat harmonization was applied to external radiomics data. Model performance was assessed using the receiver-operating-characteristics curve (AUC). RESULTS: The CV-AUCs in the training dataset were 0.88, 0.79 and 0.84 for LNI, ECE, and GS, respectively. In the combined validation dataset, the ML models could significantly predict GS with an AUC of 0.78 (p<0.05). However, validation AUCs for LNI and ECE prediction were not significant (0.57 and 0.63, respectively). Conventional PET metrics-based models had comparable AUCs for LNI (0.59, p>0.05) and ECE (0.66, p>0.05), but a lower AUC for GS (0.73, p<0.05). In general, Combat harmonization improved external validation AUCs (-0.03 to +0.18). CONCLUSION: In internal and external validation, 18F-DCFPyL-PET radiomics-based ML models predicted high postoperative GS but not LNI or ECE in intermediate- to high-risk PCa. Therefore, the clinical benefit seems to be limited. These results underline the need for external and/or multicenter validation of PET radiomics-based ML model analyses to assess their generalizability.

Incidence and survival of castration-resistant prostate cancer patients with visceral metastases: results from the Dutch CAPRI-registry.

BACKGROUND: The objective of this real-world population study is to investigate incidence and treatment of visceral metastases (VMs) in castration resistant prostate cancer (CRPC) patients and their survival. METHODS: CRPC-patients in the CAPRI-registry between 2010 and 2016 were included in the analyses and followed till 2017. Outcomes were proportion of patients radiologically screened for VMs and proportion of patients with VMs at CRPC-diagnosis and at the start of every treatment line. Groups have been created based on location of VMs (lung, liver, or both) at date of first VM diagnosis. The outcome for these groups was overall survival (OS). Statistics included descriptive analyses, Kaplan-Meier method, and Cox proportional hazard regression analysis for survival analyses. RESULTS: Of 3602 patients from the CAPRI registry, 457 patients (12.7%) were diagnosed with VMs during follow-up: 230 patients with liver, 161 with lung, and 66 with both liver and lung metastases. The proportion of patients radiologically screened for VMs increased per treatment line as did the occurrence rate of VMs. However, 80% of patients at CRPC diagnosis to 40% in the 6th line were not screened for VMs at the start of a systemic treatment. Median OS was 8.6 months for patients with liver, 18.3 with lung and 10.9 with both liver and lung metastases (p < 0.001) from date of first VM diagnosis. After correction for prognostic factors patients with lung metastases had significantly better OS than patients with liver metastases (HR 0.650, p = 0.001). CONCLUSION: This real-world analysis showed that despite the increased rate of radiological staging during follow-up, still 80% to 40% of the patients (CRPC diagnosis to 6th treatment line respectively) were not screened for VMs at the start of a systemic treatment. VMs and location of VMs are key prognostic patient characteristics, impacts survival and have implications for treatment decisions, so routine staging of CRPC-patients is warranted. CLINICAL TRIAL IDENTIFICATION: The CAPRI study is registered in the Dutch Trial Registry as NL3440 (NTR3591).

Being Transparent About Brilliant Failures: An Attempt to Use Real-World Data in a Disease Model for Patients with Castration-Resistant Prostate Cancer.

BACKGROUND: Real-world disease models spanning multiple treatment lines can provide insight into the (cost) effectiveness of treatment sequences in clinical practice. OBJECTIVE: Our objective was to explore whether a disease model based solely on real-world data (RWD) could be used to estimate the effectiveness of treatments for patients with castration-resistant prostate cancer (CRPC) that could then be suitably used in a cost-effectiveness analysis. METHODS: We developed a patient-level simulation model using patient-level data from the Dutch CAPRI registry as input parameters. Time to event (TTE) and overall survival (OS) were estimated with multivariate regression models, and type of event (i.e., next treatment or death) was estimated with multivariate logistic regression models. To test internal validity, TTE and OS from the simulation model were compared with the observed outcomes in the registry. RESULTS: Although patient characteristics and survival outcomes of the simulated data were comparable to those in the observed data (median OS 20.6 vs. 19.8 months, respectively), the disease model was less accurate in estimating differences between treatments (median OS simulated vs. observed population: 18.6 vs. 17.9 [abiraterone acetate plus prednisone], 24.0 vs. 25.0 [enzalutamide], 20.2 vs. 18.7 [docetaxel], and 20.0 vs. 23.8 months [radium-223]). CONCLUSIONS: Overall, the disease model accurately approximated the observed data in the total CRPC population. However, the disease model was unable to predict differences in survival between treatments due to unobserved differences. Therefore, the model is not suitable for cost-effectiveness analysis of CRPC treatment. Using a combination of RWD and data from randomised controlled trials to estimate treatment effectiveness may improve the model.

Symptomatic Skeletal Events and the Use of Bone Health Agents in a Real-World Treated Metastatic Castration Resistant Prostate Cancer Population: Results From the CAPRI-Study in the Netherlands.

BACKGROUND: Patients with metastatic castration resistant prostate cancer (mCRPC) are at risk of symptomatic skeletal events (SSE). Bone health agents (BHA, ie bisphosphonates and denosumab) and new life-prolonging drugs (LPDs) can delay SSEs. The aim of this study is to investigate the use of BHAs in relation to SSEs in treated real-world mCRPC population. PATIENTS AND METHODS: We included patients from the CAPRI registry who were treated with at least one LPD and diagnosed with bone metastases prior to the start of first LPD (LPD1). Outcomes were SSEs (external beam radiation therapy (EBRT) to the bone, orthopedic surgery, pathologic fracture or spinal cord compression) and SSE-free survival (SSE-FS) since LPD1. RESULTS: One-thousand nine hundred and twenty-three patients were included with a median follow-up from LPD1 of 16.7 months. Fifty-two percent (n = 996) started BHA prior or within 4 weeks after the start of LPD1 (early BHA). In total, 41% experienced at least one SSE. SSE incidence rate was 0.29 per patient year for patients without BHA and 0.27 for patients with early BHA. Median SSE-FS from LPD1 was 12.9 months. SSE-FS was longer in patients who started BHA early versus patients without BHA (13.2 vs. 11.0 months, P = .001). CONCLUSION: In a real-world population we observed an undertreatment with BHAs, although patients with early BHA use had lower incidence rates of SSEs and longer SSE-FS. This finding was irrespective of type of SSE and presence of risk factors. In addition to LPD treatment, timely initiation of BHAs is recommended in bone metastatic CRPC-patients with both pain and/or opioid use and prior SSE.

Detection of Recurrent Prostate Cancer Using Prostate-specific Membrane Antigen Positron Emission Tomography in Patients not Meeting the Phoenix Criteria for Biochemical Recurrence After Curative Radiotherapy.

Biochemical recurrence of prostate cancer (PCa) after curative radiotherapy is defined as a prostate-specific antigen (PSA) rise of ≥2 ng/ml above the nadir ("Phoenix criteria", 2005). With the introduction of prostate-specific membrane antigen positron emission tomography (PSMA-PET), the ability to localise PCa recurrences has increased markedly. Here, we reviewed 315 patients scanned with PSMA-PET after curative radiotherapy in the Prostate Cancer Network Amsterdam (2015-2018). Sixty-three patients (20.3%) were scanned below the Phoenix threshold (PSA rise <2.0 ng/ml). In 53 of these patients (84.1%), PSMA-PET-avid lesions were detected nonetheless: 21 patients (33.3%) revealed a local recurrence as a single site of disease, 32 patients (50.8%) harboured metastatic PCa. Besides rising PSA, no predictors were identified that prompted early PSMA-PET imaging. In this communication, we report on the frequent detection of metastatic PCa with PSMA-PET in men below the Phoenix PSA threshold. These findings are a plea for re-evaluation of current diagnostic work-up for rising PSA values after radiotherapy, as early detection of recurrences might refine salvage and/or adjuvant therapies. PATIENT SUMMARY: This study reports on the unexpected detection of prostate cancer (PCa) recurrences with prostate-specific membrane antigen positron emission tomography in patients treated with radiotherapy. This calls for re-evaluation of the current criteria for recurrent PCa after radiotherapy.

Variation in the Prescription of Androgen Deprivation Therapy in Intermediate- and High-risk Prostate Cancer Patients Treated with Radiotherapy in the Netherlands, and Adherence to European Association of Urology Guidelines: A Population-based Study.

BACKGROUND: According to (inter-)national guidelines, (neo-)adjuvant and concurrent androgen deprivation therapy (ADT) in combination with external beam radiotherapy (EBRT) is optional for intermediate-risk prostate cancer (PCa) patients and is the recommended standard treatment for high-risk PCa patients. OBJECTIVE: The aim of this study is to provide insight into the prescription of ADT in intermediate- and high-risk PCa patients treated with EBRT in the Netherlands, and to evaluate adherence to European Association of Urology guidelines and factors affecting prescription. DESIGN, SETTING, AND PARTICIPANTS: All intermediate- and high-risk PCa patients between October 2015 and April 2016 were identified through the population-based Netherlands Cancer Registry. Variation in the prescription of ADT in patients with EBRT was evaluated. Multivariable multilevel logistic regression analyses were performed to determine the probability of ADT and to examine the role of patient-, tumour-, and hospital-related factors. RESULTS AND LIMITATIONS: Overall, 29% of patients with intermediate-risk PCa received ADT varying from 3% to 73% between institutions. From the multivariable regression analysis, higher Gleason grade, magnetic resonance imaging, and computed tomography (CT)-positron-emission tomography/CT prior to radiotherapy appeared to be associated with increased prescription of ADT. Among high-risk patients, 83% received ADT, varying from 57% to 100% between departments. A higher prostate-specific antigen level, more advanced tumour stage, and a higher Gleason grade were associated with increased prescription. CONCLUSIONS: Less than one-third of intermediate-risk PCa patients treated with EBRT receive ADT. The variation in the prescription of ADT between different institutions is substantial. This suggests that the prescription is largely dependent on different institutional policies. The guideline adherence in high-risk PCa is fairly good, as the vast majority of patients received ADT as recommended. However, given the clear recommendations in the guidelines, adherence could be improved. PATIENT SUMMARY: In this review, we looked at the variation of hormonal treatment in intermediate- and high-risk prostate cancer patients. We found substantial variation between institutions.

Third-line Life-prolonging Drug Treatment in a Real-world Metastatic Castration-resistant Prostate Cancer Population: Results from the Dutch Castration-resistant Prostate Cancer Registry.

BACKGROUND: Evidence concerning third-line life-prolonging drugs (LPDs) in the treatment of metastatic castration-resistant prostate cancer (mCRPC) patients is incomplete. OBJECTIVE: To evaluate third-line LPD outcomes in a real-world cohort of mCRPC patients, identify variables associated with overall survival (OS), and establish a prognostic model. DESIGN, SETTING, AND PARTICIPANTS: Patients with mCRPC who were progressive on second-line LPD before July 1, 2017 were retrospectively identified from the Dutch Castration-resistant Prostate Cancer Registry (CAPRI) and followed until December 31, 2017. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Association of potential risk factors with OS was tested by Cox proportional hazard models after multiple imputation of missing baseline characteristics. A predictive score was computed from the regression coefficient and used to classify patients into risk groups. RESULTS AND LIMITATIONS: Of 1011 mCRPC patients progressive on second-line LPD, 602 (60%) received third-line LPD. Patients receiving third-line LPD had a more favorable prognostic profile at baseline and longer median OS than patients with best supportive care (10.4 vs 2.4 mo, p < 0.001). Eastern Cooperative Oncology Group performance status 1 and ≥2 (hazard ratio [HR] 1.51, p < 0.007 and HR 3.08, p < 0.001, respectively), opioid use (HR 1.55, p = 0.019), visceral metastases (HR 2.09, p < 0.001), hemoglobin <7 mmol/l (HR 1.44, p < 0.002), prostate-specific antigen ≥130 µg/l (HR 1.48, p = 0.001), alkaline phosphatase ≥170 U/l (HR 1.52, p < 0.001), and lactate dehydrogenase ≥250 U/l (HR 1.44; p = 0.015) were associated with shorter survival. Harrell's C-index was 0.74. The median OS values for low-, low-intermediate-, high-intermediate-, and high-risk groups were 14, 7.7, 4.7, and 1.8 mo, respectively. Limitations include the retrospective design. CONCLUSIONS: We developed a prognostic model and identified a subgroup of patients in whom third-line LPD treatment has no meaningful benefit. Our results need to be confirmed by prospective clinical trials. PATIENT SUMMARY: We reported outcomes from third-line life-prolonging drugs in metastatic prostate cancer patients and developed a prognostic model that could be used to guide treatment decisions.

Renal biopsies performed before versus during ablation of T1 renal tumors: implications for prevention of overtreatment and follow-up.

PURPOSE: To assess the difference between renal mass biopsy (RMB) performed either before or during the ablation procedure. METHODS: A retrospective multicenter study was performed in patients with a cT1 renal mass treated with ablation between January 2007 and July 2019, including a search in the national pathology database for patients with a RMB planned for ablation. Patient and tumor characteristics and information on malignant, benign, and non-diagnostic biopsy results were collected to establish rates of overtreatment and number of ablations avoided in case of benign or non-diagnostic histology. RESULTS: RMB was performed in 714 patients, of which 231 patients received biopsy before planned ablation, and 483 patients at the time of ablation. Pathology results before ablation were malignant in 63% (145/231), benign in 20% (46/231) and non-diagnostic in 17% (40/231). Pathology results at the time of ablation were malignant in 67.5% (326/483), benign in 16.8% (81/483) and non-diagnostic in 15.7% (76/483), leading to a total of 32.5% of ablation of benign or non-diagnostic lesions. Of the patients with a benign biopsy obtained before ablation, 80.4% (37/46) chose not to undergo ablation. Patients with inconclusive biopsy before planned ablation chose an informed individualized approach including ablation, repeated biopsy, or no intervention in 56%, 34% and 10%. CONCLUSION: This study emphasizes the importance of obtaining a biopsy prior to the ablation procedure in a separate session to lower the rate of potentially unnecessary ablations.

Machine learning-based analysis of [18F]DCFPyL PET radiomics for risk stratification in primary prostate cancer.

PURPOSE: Quantitative prostate-specific membrane antigen (PSMA) PET analysis may provide for non-invasive and objective risk stratification of primary prostate cancer (PCa) patients. We determined the ability of machine learning-based analysis of quantitative [18F]DCFPyL PET metrics to predict metastatic disease or high-risk pathological tumor features. METHODS: In a prospective cohort study, 76 patients with intermediate- to high-risk PCa scheduled for robot-assisted radical prostatectomy with extended pelvic lymph node dissection underwent pre-operative [18F]DCFPyL PET-CT. Primary tumors were delineated using 50-70% peak isocontour thresholds on images with and without partial-volume correction (PVC). Four hundred and eighty standardized radiomic features were extracted per tumor. Random forest models were trained to predict lymph node involvement (LNI), presence of any metastasis, Gleason score ≥ 8, and presence of extracapsular extension (ECE). For comparison, models were also trained using standard PET features (SUVs, volume, total PSMA uptake). Model performance was validated using 50 times repeated 5-fold cross-validation yielding the mean receiver-operator characteristic curve AUC. RESULTS: The radiomics-based machine learning models predicted LNI (AUC 0.86 ± 0.15, p < 0.01), nodal or distant metastasis (AUC 0.86 ± 0.14, p < 0.01), Gleason score (0.81 ± 0.16, p < 0.01), and ECE (0.76 ± 0.12, p < 0.01). The highest AUCs reached using standard PET metrics were lower than those of radiomics-based models. For LNI and metastasis prediction, PVC and a higher delineation threshold improved model stability. Machine learning pre-processing methods had a minor impact on model performance. CONCLUSION: Machine learning-based analysis of quantitative [18F]DCFPyL PET metrics can predict LNI and high-risk pathological tumor features in primary PCa patients. These findings indicate that PSMA expression detected on PET is related to both primary tumor histopathology and metastatic tendency. Multicenter external validation is needed to determine the benefits of using radiomics versus standard PET metrics in clinical practice.

Patient reported outcome measures concerning urinary incontinence after robot assisted radical prostatectomy: development and validation of an online prediction model using clinical parameters, lower urinary tract symptoms and surgical experience.

The prediction of post-prostatectomy incontinence (PPI) after robot-assisted radical prostatectomy (RARP) depends on multiple clinical, anatomical and surgical factors. There are only few risk formulas, tables or nomograms predicting PPI that may assist clinicians and their patients in adequate risk counseling on postoperative side-effects. Prospective data collection of 1814 patients who underwent RARP between 2009 and 2017 was done. Pre-operative parameters were age, body mass index (BMI), prostate volume, the American Society of Anesthesiologists (ASA) score, severity of Lower Urinary Tract Symptoms (LUTS), type of planned nerve-sparing surgery and surgical experience. The continence status was reported using Patient Reported Outcome Measurements (PROMs) using the validated pad-use questionnaire EPIC26. Continence was defined as either the use of zero pads or one safety pad. Multivariable logistic regression analysis was performed to identify predictors of PPI within one year after RARP. An online prediction tool was developed and validated. The median follow-up was 36 months (range 12-108). The response rate was high at 85.2%. A total of 85% (1537/1814) of patients was continent on follow-up. One-year continence rate was 80.1% (95% CI 78.3-81.9%) (1453/1814) and increased to 87.4% (95% CI 85.4-89.4%) after 5 years. On multivariable analysis, severity of LUTS (OR = 0.56 p = 0.004), higher age (OR = 0.73 p = 0.049), extend of nerve-sparing surgery (OR = 0.60 p = 0.001) and surgeon experience (OR = 1.48 p = 0.025) were significant independent predictors for PPI. The online prediction model performed well in predicting continence status with poor discrimination and good calibration. An intuitive online tool was developed to predict PPI after RARP that may assist clinicians and their patients in counseling of treatment.

Real-world Outcomes of Sequential Androgen-receptor Targeting Therapies with or Without Interposed Life-prolonging Drugs in Metastatic Castration-resistant Prostate Cancer: Results from the Dutch Castration-resistant Prostate Cancer Registry.

BACKGROUND: Cross resistance between androgen-receptor targeting therapies (ARTs) (abiraterone acetate plus prednisone [ABI+P] or enzalutamide [ENZ]) for treatment of metastatic castration-resistant prostate cancer (mCRPC) may affect responses to second ART (ART2). OBJECTIVE: To establish treatment duration and prostate-specific antigen (PSA) response of ART2 in real-world mCRPC patients treated with or without other life-prolonging drugs (LPDs; ie, docetaxel, cabazitaxel, or radium-223) between ART1 and ART2. DESIGN, SETTING, AND PARTICIPANTS: Castration-resistant prostate cancer patients, diagnosed between 2010 and 2016 were retrospectively registered in Castration-resistant Prostate Cancer Registry (CAPRI). Patients treated with both ARTs were clustered into two subgroups: ART1>ART2 or ART1>LPD>ART2. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Outcomes were ≥50% PSA response and treatment duration of ART2. Descriptive statistics and binary logistic regression after multiple imputations were performed. RESULTS AND LIMITATIONS: A total of 273 patients were included with a median follow-up of 8.4 mo from ART2. Patients with ART1>ART2 were older and had favourable prognostic characteristics at ART2 baseline compared with patients with ART1>LPD>ART2. No differences between ART1>ART2 and ART1>LPD>ART2 were found in PSA response and treatment duration. Multivariate analysis suggested that PSA response of ART2 was less likely in patients with visceral metastases (odds ratio [OR] 0.143, p=0.04) and more likely in patients with a relatively longer duration of androgen-deprivation treatment (OR 1.028, p=0.01) and with ABI + P before ENZ (OR 3.192, p=0.02). A major limitation of this study was missing data, a common problem in retrospective observational research. CONCLUSIONS: The effect of ART2 seems to be low, with a low PSA response rate and a short treatment duration irrespective of interposed chemotherapy or radium-223, especially in patients with short time on castration, visceral disease, and ENZ before ABI+P. PATIENT SUMMARY: We observed no differences in outcomes of patients treated with sequential abiraterone acetate plus prednisone (ABI+P) and enzalutamide (ENZ) with or without interposed chemotherapy or radium-223. In general, outcomes were lower than those in randomised trials, questioning the additional effect of second treatment with ABI+P or ENZ in daily practice.

Hospital-specific probability of cystectomy affects survival from muscle-invasive bladder cancer.

OBJECTIVES: Radical cystectomies (RCs) are increasingly centralized, but bladder cancer can be diagnosed in every hospital The aim of this study is to assess the variation between hospitals of diagnosis in a patient's chance to undergo a RC before and after the volume criteria for RCs, to identify factors associated with this variation and to assess its effect on survival. METHODS AND MATERIALS: Patients diagnosed with muscle-invasive bladder cancer (cT2-4a,N0/X,M0/X) without nodal or distant metastases between 2008 and 2016 were identified through the Netherlands Cancer Registry. Multilevel logistic regression analysis was used to investigate the hospital specific probability of undergoing a cystectomy. Cox proportional hazard regression analysis was used to assess the case-mix adjusted effect of hospital-specific probabilities on survival. RESULTS: Of the 9,215 included patients, 4,513 (49%) underwent a RC. The percentage of RCs varied between 7% and 83% by hospital of diagnosis before the introduction of the first volume criteria (i.e., 2008-2009; minimum of 10 RCs). This variation decreased slightly to 17%-77% after establishment of the second volume criteria (i.e., 2015-2016; minimum of 20 RCs). Age, cT-stage and comorbidity were inversely and socioeconomic status was positively associated with RC. Both being diagnosed in a community hospital and/or being diagnosed in a hospital fulfilling the RC volume criteria were associated with increased use of RC compared to academic hospitals and hospitals not fulfilling the volume criteria. For each 10% increase in the percentage of RC in the hospital of diagnosis, 2-year case-mix adjusted survival increased 4% (hazard ratio 0.96, 95% confidence interval 0.94-0.98). CONCLUSION: Probability of RC varied between hospitals of diagnosis and affected 2-year overall survival. Undergoing a RC was associated with age, cT-stage, socioeconomic status, type of hospital, and whether the hospital of diagnosis fulfilled the RC volume criteria. Future research is needed to identify patient, tumor, and hospital characteristics affecting utilization of curative treatment as this may benefit overall survival.

Repeatability of Quantitative 18F-DCFPyL PET/CT Measurements in Metastatic Prostate Cancer.

Quantitative evaluation of radiolabeled prostate-specific membrane antigen (PSMA) PET scans may be used to monitor treatment response in patients with prostate cancer (PCa). To interpret longitudinal differences in PSMA uptake, the intrinsic variability of tracer uptake in PCa lesions needs to be defined. The aim of this study was to investigate the repeatability of quantitative PET/CT measurements using 18F-DCFPyL ([2-(3-(1-carboxy-5-[(6-18F-fluoro-pyridine-3-carbonyl)-amino]-pentyl)-ureido)-pentanedioic acid], a second-generation 18F-PSMA-ligand) in patients with PCa. Methods: Twelve patients with metastatic PCa were prospectively included, of whom 2 were excluded from final analyses. Patients received 2 whole-body 18F-DCFPyL PET/CT scans (median dose, 317 MBq; uptake time, 120 min) within a median of 4 d (range, 1-11 d). After semiautomatic (isocontour-based) tumor delineation, the following lesion-based metrics were derived: mean, peak, and maximum tumor-to-blood ratio; SUVmean, SUVpeak, and SUVmax normalized to body weight; tumor volume; and total lesion uptake (TLU). Additionally, patient-based total tumor volume (TTV) (sum of PSMA-positive tumor volumes) and total tumor burden (TTB) (sum of all lesion TLUs) were derived. Repeatability was analyzed using repeatability coefficients (RC) and intraclass correlation coefficients. Additionally, the effect of point-spread function (PSF) image reconstruction on the repeatability of uptake metrics was evaluated. Results: In total, 36 18F-DCFPyL PET-positive lesions were analyzed (≤5 lesions per patient). The RCs for mean, peak, and maximum tumor-to-blood ratio were 31.8%, 31.7%, and 37.3%, respectively. For SUVmean, SUVpeak, and SUVmax, the RCs were 24.4%, 25.3%, and 31.0%, respectively. All intraclass correlation coefficients were at least 0.97. Tumor volume delineations were quite repeatable, with an RC of 28.1% for individual lesion volumes and 17.0% for TTV. TTB had an RC of 23.2% and 33.4% when based on SUVmean and mean tumor-to-blood ratio, respectively. Small lesions (<4.2 cm3) had worse repeatability for volume measurements. The repeatability of SUVpeak, TLU, and all patient-level metrics was not affected by PSF reconstruction. Conclusion:18F-DCFPyL uptake measurements are quite repeatable and can be used for clinical validation in future treatment response assessment studies. Patient-based TTV may be preferred for multicenter studies because its repeatability was both high and robust to different image reconstructions.

Lesion Detection and Interobserver Agreement with Advanced Image Reconstruction for 18F-DCFPyL PET/CT in Patients with Biochemically Recurrent Prostate Cancer.

Biochemically recurrent prostate cancer (BCR) is the main indication to perform prostate-specific membrane antigen PET/CT. However, localizing BCR with prostate-specific membrane antigen PET/CT remains challenging in patients with low prostate-specific antigen (PSA) values. Here, we studied the impact of advanced PET image reconstruction methods on BCR localization and interobserver agreement with 18F-DCFPyL PET/CT scans in patients with BCR and low PSA values. Methods: Twenty-four patients with BCR and a PSA level of less than 2.0 ng/mL were included. PET images were reconstructed with 4-mm voxels and 2-mm voxels, both with and without point-spread function. All scans were interpreted by 4 nuclear medicine physicians. Additionally, PET examinations of 5 patients with primary prostate cancer and confirmed absence of lymph node metastases (after lymph node dissection) were included, to assess the risk of introducing false-positive findings when using advanced reconstruction. Calculation of BCR localization rates (scan positivity) was based on consensus among our readers (≥3 readers regarding a scan positive for BCR), as well as the individual scan interpretations of the readers. Results: In the consensus analysis, BCR localization rates were not higher using advanced reconstruction (62.5%-66.7%) than using 4-mm reconstruction (62.5%). On the basis of individual readings, however, more scans were positive using 2-mm reconstruction (74.0%; 95% confidence interval [CI], 65.0%-82.9%) (P = 0.027) and 2-mm reconstruction with point-spread function (75.0%; 95% CI, 66.2%-83.8%) (P = 0.014) than 4-mm reconstruction (65.6%; 95% CI, 56.0%-75.3%). A higher number of lesions was detected on the 2-mm scans (median, 2 lesions; interquartile range, 1-3) than the 4-mm scans (median, 1; interquartile range, 0-3; P = 0.008). The advanced reconstruction methods did not increase interobserver agreement (80.6%-84.7%), compared with the 4-mm scans (75.7%, P = 0.08-0.25). In the patients with primary prostate cancer, an equal number of false-positive lesions was observed among the different reconstruction methods (overall, n = 13). Conclusion: Applying advanced image reconstruction for 18F-DCFPyL PET/CT scans did not increase BCR localization in patients with BCR and low PSA values (reader consensus). Yet, the increased number of positive individual readings may imply that further development of image reconstruction methods holds potential to improve BCR localization. No improved interobserver agreement was observed with advanced reconstruction compared with standard 4-mm reconstruction.

Health-related Quality of Life and Pain in a Real-world Castration-resistant Prostate Cancer Population: Results From the PRO-CAPRI Study in the Netherlands.

BACKGROUND: The purpose of this study was to determine generic, cancer-specific, and prostate cancer-specific health-related quality of life (HRQoL), pain and changes over time in patients with metastatic castration-resistant prostate cancer (mCRPC) in daily practice. PATIENTS AND METHODS: PRO-CAPRI is an observational, prospective study in 10 hospitals in the Netherlands. Patients with mCRPC completed the EQ-5D, European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30), and Brief Pain Inventory-Short Form (BPI-SF) every 3 months and European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire-Prostate Cancer Module (EORTC QLQ-PR25) every 6 months for a maximum of 2 years. Subgroups were identified based on chemotherapy pretreatment. Outcomes were generic, cancer-specific, and prostate cancer-specific HRQoL and self-reported pain. Descriptive statistics were performed including changes over time and minimal important differences (MID) between subgroups. RESULTS: In total, 151 included patients answered 873 questionnaires. The median follow-up from the start of the study was 19.5 months, and 84% were treated with at least 1 life-prolonging agent. Overall, patients were in good clinical condition (Eatern Cooperative Oncology Group performance status 0-1 in 78%) with normal baseline hemoglobin, lactate dehydrogenase, and alkaline phosphatase. At inclusion, generic HRQoL was high with a mean EQ visual analog score of 73.2 out of 100. The lowest scores were reported on role and physical functioning (mean scores of 69 and 76 of 100, respectively), and fatigue, pain, and insomnia were the most impaired domains. These domains deteriorated in > 50% of patients. CONCLUSION: Although most patients were treated with new treatments during follow-up, mCRPC has a negative impact on HRQoL with deterioration in all domains over time, especially role and physical functioning. These domains need specific attention during follow-up to maintain HRQoL as long as possible by timely start of adequate supportive care management.

A Prospective Single-Arm Phase 2 Study of Stereotactic Magnetic Resonance Guided Adaptive Radiation Therapy for Prostate Cancer: Early Toxicity Results.

PURPOSE: Use of stereotactic body radiation therapy (SBRT) is increasing in patients with localized prostate cancer, but concerns about early and late gastrointestinal (GI) and genitourinary (GU) toxicity exist after moderately or extremely hypofractionated radiation therapy schemes. Magnetic resonance guided radiation therapy (MRgRT) was clinically introduced in 2014. MrgRT allows for SBRT delivery with smaller uncertainty margins and permits daily adaptive planning. A phase 2 study in patients with localized prostate cancer was performed to study early GI and GU toxicity after SBRT using MRgRT. METHODS AND MATERIALS: One hundred one patients with clinical stage T1-3bN0M0 prostate cancer were enrolled in this prospective phase 2 study. All but 4 patients had intermediate- or high-risk prostate cancer, and 82.2% received adjuvant hormonal treatment. MRgRT was delivered in 5 fractions of 7.25 Gy to the target volume using daily plan adaptation with simultaneous relative sparing of the urethra to a dose of 6.5 Gy per fraction. Early toxicity was studied using both clinician- (Common Terminology Criteria for Adverse Events and Radiation Therapy Oncology Group) and patient-reported outcome measurements (European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-C30, Quality of Life Questionnaire PR25, and International Prostate Symptom Scoring). RESULTS: The maximum cumulative grade ≥2 early GU and GI toxicity measured by any symptom at any study time point was 23.8% and 5.0%, respectively. No early grade 3 GI toxicity was observed. Early grade 3 GU toxicity was 0% and 5.9% according to the Common Terminology Criteria for Adverse Events and Radiation Therapy Oncology Group and scoring systems, respectively, as a result of different grading of radiation cystitis. The low incidence of early GI toxicity was confirmed by patient-reported outcome data. GU grade ≥2 toxicity peaked to 19.8% at the end of MRgRT, followed by a return to the baseline average score at 3-month follow-up. CONCLUSIONS: This prospective study of MRgRT in patients with localized prostate cancer observed a low incidence of early GI and GU toxicity, both in clinician- and patient-reported outcome measurements.

Simplified Methods for Quantification of 18F-DCFPyL Uptake in Patients with Prostate Cancer.

Radiolabeled prostate-specific membrane antigen (PSMA) PET has demonstrated promising results for prostate cancer (PCa) imaging. Quantification of PSMA radiotracer uptake is desired as it enables reliable interpretation of PET images, use of PSMA uptake as an imaging biomarker for tumor characterization, and evaluation of treatment effects. The aim of this study was to perform a full pharmacokinetic analysis of 2-(3-(1-carboxy-5-[(6-18F-fluoro-pyridine-3-carbonyl)-amino]-pentyl)-ureido)-pentanedioic acid (18F-DCFPyL), a second-generation 18F-labeled PSMA ligand. On the basis of the pharmacokinetic analysis (reference method), simplified methods for quantification of 18F-DCFPyL uptake were validated. Methods: Eight patients with metastasized PCa were included. Dynamic PET acquisitions were performed at 0-60 and 90-120 min after injection of a median dose of 313 MBq of 18F-DCFPyL (range, 292-314 MBq). Continuous and manual arterial blood sampling provided calibrated plasma tracer input functions. Time-activity curves were derived for each PCa metastasis, and 18F-DCFPyL kinetics were described using standard plasma input tissue-compartment models. Simplified methods for quantification of 18F-DCFPyL uptake (SUVs; tumor-to-blood ratios [TBRs]) were correlated with kinetic parameter estimates obtained from full pharmacokinetic analysis. Results: In total, 46 metastases were evaluated. A reversible 2-tissue-compartment model was preferred for 18F-DCFPyL kinetics in 59% of the metastases. The observed k4 was small, however, resulting in nearly irreversible kinetics during the course of the PET study. Hence, k4 was fixated (0.015) and net influx rate, Ki, was preferred as the reference kinetic parameter. Whole-blood TBR provided an excellent correlation with Ki from full kinetic analysis (R2 = 0.97). This TBR could be simplified further by replacing the blood samples with an image-based, single measurement of blood activity in the ascending aorta (image-based TBR, R2 = 0.96). SUV correlated poorly with Ki (R2 = 0.47 and R2 = 0.60 for SUV normalized to body weight and lean body mass, respectively), most likely because of deviant blood activity concentrations (i.e., tumor tracer input) in patients with higher tumor volumes. Conclusion:18F-DCFPyL kinetics in PCa metastases are best described by a reversible 2-tissue-compartment model. Image-based TBRs were validated as a simplified method to quantify 18F-DCFPyL uptake and might be applied to clinical, whole-body PET scans. SUV does not provide reliable quantification of 18F-DCFPyL uptake.