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Hausmann D, Rupp N, Kuzmanic B, Spielhofer N, Heimer J, Koelzer V, Nowak M, Gampp C, Hefermehl L, Kubik-Huch RA, Singer G, Burger IA. How Prostate Cancer Growth Patterns Impact Detection and Interreader Agreement on Multiparametric MRI. Acad Radiol 2024:S1076-6332(24)00828-6. [PMID: 39643467 DOI: 10.1016/j.acra.2024.10.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2024] [Revised: 10/22/2024] [Accepted: 10/22/2024] [Indexed: 12/09/2024]
Abstract
RATIONALE AND OBJECTIVES Multiparametric MRI (mpMRI) substantially improves the detection of significant prostate carcinoma (PCa) compared to systematic biopsy. Nevertheless, mpMRI can overlook aggressive forms of PCa. Recent studies showed, that infiltrative growth (INF) has less restricted diffusion. This study aims to explore the impact of growth patterns on the detection of lesions. MATERIALS AND METHODS This retrospective study analyzed 52 patients who underwent radical prostatectomy, with preoperative mpMRI. For each patient, one dominant lesion was identified on one whole-mount prostatectomy section. Two pathologists (P1, P2) independently classified the growth pattern whether as expansive (EXP) being defined with at least three 5mm² regions of interest consisting entirely of carcinoma without benign glands or else as infiltrative (INF). Two radiologists (R1, R2) independently classified selected lesions according to PI-RADSv2.1. based on pathological localization. Apparent diffusion coefficient (ADC) values were measured in correlation with matched histopathology slides. Interreader-agreement was evaluated using weighted Cohen's Kappa. The relationship between PI-RADS scores and pathological diagnoses was analyzed using logistic regression. RESULTS Pathologic lesion characterization regarding growth patterns achieved almost perfect agreement (κ = 0.88), so did PI-RADS classification of mpMRI (κ = 0.90). PI-RADS scores correlated significantly with EXP growth patterns. Average ADC values were lower for EXP lesions (0.83×10-3 mm2/s, CI: 0.72-0.94×10-3 mm2/s) compared to INF lesions (0.97×10-3 mm2/s, CI: 0.86-1.07×10-3 mm2/s; p = 0.08). On T2 images, 8 of 28 (29%) INF lesions and 1 of 24 (4%) EXP lesions were not visible. CONCLUSION PCa missed on mpMRI more frequently demonstrate INF growth patterns. Lesions with EXP growth patterns show lower ADC values and have higher PI-RADS scores.
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Rupp NJ, Freiberger SN, Ferraro DA, Laudicella R, Heimer J, Muehlematter UJ, Poyet C, Moch H, Eberli D, Rüschoff JH, Burger IA. Immunohistochemical ERG positivity is associated with decreased PSMA expression and lower visibility in corresponding [ 68Ga]Ga-PSMA-11 PET scans of primary prostate cancer. Eur J Nucl Med Mol Imaging 2024; 52:305-313. [PMID: 39083067 PMCID: PMC11599624 DOI: 10.1007/s00259-024-06856-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2024] [Accepted: 07/17/2024] [Indexed: 11/27/2024]
Abstract
PURPOSE TMPRSS2:ERG gene fusion negatively regulates PSMA expression in prostate adenocarcinoma (PCa) cell lines. Therefore, immunohistochemical (IHC) ERG expression, a surrogate for an underlying ERG rearrangement, and PSMA expression patterns in radical prostatectomy (RPE) specimens of primary PCa, including corresponding PSMA-PET scans were investigated. METHODS Two cohorts of RPE samples (total n=148): In cohort #1 (n=62 patients) with available RPE and preoperative [68Ga]Ga-PSMA-11 PET, WHO/ISUP grade groups, IHC-ERG (positive vs. negative) and IHC-PSMA expression (% PSMA-negative tumour area, PSMA%neg) were correlated with the corresponding SUVmax. In the second cohort #2 (n=86 patients) including RPE only, same histopathological parameters were evaluated. RESULTS Cohort #1: PCa with IHC-ERG expression (35.5%) showed significantly lower IHC-PSMA expression and lower SUVmax values on the corresponding PET scans. Eight of 9 PCa with negative PSMA-PET scans had IHC-ERG positivity, and confirmed TMPRSS2::ERG rearrangement. In IHC-PSMA positive PCa, IHC-ERG positivity was significantly associated with lower SUVmax values. In cohort #2, findings of higher IHC-PSMA%neg and IHC-ERG expression was confirmed with only 0-10% PSMA%neg tumour areas in IHC-ERG-negative PCa. CONCLUSION IHC-ERG expression is significantly associated with more heterogeneous and lower IHC-PSMA tissue expression in two independent RPE cohorts. There is a strong association of ERG positivity in RPE tissue with lower [68Ga]Ga-PSMA-11 uptake on corresponding PET scans. Results may serve as a base for future biomarker development to enable tumour-tailored, individualized imaging approaches.
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Tiberiu D, Spielhofer N, Heimer J, Sauter AW, Popescu C, Hausmann D, Manser JL, Eid K, Kubik-Huch RA, Burger IA. Quantification of [ 99mTc]Tc-HDP bone SPECT/CT: can we improve the body weight based standardized uptake value with a more robust normalization? EJNMMI Res 2024; 14:111. [PMID: 39560874 DOI: 10.1186/s13550-024-01167-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2024] [Accepted: 10/24/2024] [Indexed: 11/20/2024] Open
Abstract
BACKGROUND The introduction of quantitative SPECT/CT allows more objective assessments of tracer accumulation in SPECT. However standardized uptake values (SUV) still do not play a big role for orthopedic or oncologic questions. With a more reliable normalization, the use of quantitative measures might also be of use for a more objective assessment of lesions. We retrospectively included patients that received a quantitative [99mTc]-HDP bone SPECT/CT scan of the lumbar spine for 4 body weight (BW) categories. Measurements of bone activity (kBq/cc) and bone density in Hounsfield Units (HU) in a standard volume of interest in the femur, the first and the fifth lumbar vertebra of all patients, without active disease within these regions was made. Correlations between tracer uptake and clinical parameters (BW, height, age, gender) were assessed with a multiple regression and based on the model coefficients, a correction formula was calculated and applied. RESULTS The strongest correlation between measured activity in L1 and patient parameters was found for BW (r= -0.64, p < 0.001), compared to height (r = -0.28, p = 0.002) and age (r = -0.34, p = 0.001). Furthermore, there was a weak positive correlation between tracer accumulation and bone density (r: 0.35, p < 0.001). Using standard normalization with BW there was a very weak positive correlation between SUVBW at L1 and BW with a slight overestimation in heavier subjects (r = 0.15, p = 0.09). The calculated correction based on the multiple regression of activity as dependent variable, and weight, age and bone density as significant predictors resulted in more robust uptake values with non-significant associations to BW, height, age or density. However, there was still a wide interindividual range of values for normalized bone activity. CONCLUSION Using an age, bone density and weight-based normalization significantly decreased the interindividual variability of normal uptake on quantitative SPECT/CT compared to the regularly used BW adjusted SUVBW. However, a generalized normalization is difficult in the presence of strong patient effects, not attributable to the measured clinical variables.
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Wang T, Sharma AK, Wu C, Maushart CI, Ghosh A, Yang W, Stefanicka P, Kovanicova Z, Ukropec J, Zhang J, Arnold M, Klug M, De Bock K, Schneider U, Popescu C, Zheng B, Ding L, Long F, Dewal RS, Moser C, Sun W, Dong H, Takes M, Suelberg D, Mameghani A, Nocito A, Zech CJ, Chirindel A, Wild D, Burger IA, Schön MR, Dietrich A, Gao M, Heine M, Sun Y, Vargas-Castillo A, Søberg S, Scheele C, Balaz M, Blüher M, Betz MJ, Spiegelman BM, Wolfrum C. Single-nucleus transcriptomics identifies separate classes of UCP1 and futile cycle adipocytes. Cell Metab 2024; 36:2130-2145.e7. [PMID: 39084216 DOI: 10.1016/j.cmet.2024.07.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 04/22/2024] [Accepted: 07/08/2024] [Indexed: 08/02/2024]
Abstract
Adipose tissue can recruit catabolic adipocytes that utilize chemical energy to dissipate heat. This process occurs either by uncoupled respiration through uncoupling protein 1 (UCP1) or by utilizing ATP-dependent futile cycles (FCs). However, it remains unclear how these pathways coexist since both processes rely on the mitochondrial membrane potential. Utilizing single-nucleus RNA sequencing to deconvolute the heterogeneity of subcutaneous adipose tissue in mice and humans, we identify at least 2 distinct subpopulations of beige adipocytes: FC-adipocytes and UCP1-beige adipocytes. Importantly, we demonstrate that the FC-adipocyte subpopulation is highly metabolically active and utilizes FCs to dissipate energy, thus contributing to thermogenesis independent of Ucp1. Furthermore, FC-adipocytes are important drivers of systemic energy homeostasis and linked to glucose metabolism and obesity resistance in humans. Taken together, our findings identify a noncanonical thermogenic adipocyte subpopulation, which could be an important regulator of energy homeostasis in mammals.
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Laudicella R, Comelli A, Schwyzer M, Stefano A, Konukoglu E, Messerli M, Baldari S, Eberli D, Burger IA. Correction: PSMA‑positive prostatic volume prediction with deep learning based on T2‑weighted MRI. LA RADIOLOGIA MEDICA 2024; 129:1428. [PMID: 39180615 PMCID: PMC11379721 DOI: 10.1007/s11547-024-01829-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/26/2024]
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Laudicella R, Comelli A, Schwyzer M, Stefano A, Konukoglu E, Messerli M, Baldari S, Eberli D, Burger IA. PSMA-positive prostatic volume prediction with deep learning based on T2-weighted MRI. LA RADIOLOGIA MEDICA 2024; 129:901-911. [PMID: 38700556 PMCID: PMC11168990 DOI: 10.1007/s11547-024-01820-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 04/16/2024] [Indexed: 05/28/2024]
Abstract
PURPOSE High PSMA expression might be correlated with structural characteristics such as growth patterns on histopathology, not recognized by the human eye on MRI images. Deep structural image analysis might be able to detect such differences and therefore predict if a lesion would be PSMA positive. Therefore, we aimed to train a neural network based on PSMA PET/MRI scans to predict increased prostatic PSMA uptake based on the axial T2-weighted sequence alone. MATERIAL AND METHODS All patients undergoing simultaneous PSMA PET/MRI for PCa staging or biopsy guidance between April 2016 and December 2020 at our institution were selected. To increase the specificity of our model, the prostatic beds on PSMA PET scans were dichotomized in positive and negative regions using an SUV threshold greater than 4 to generate a PSMA PET map. Then, a C-ENet was trained on the T2 images of the training cohort to generate a predictive prostatic PSMA PET map. RESULTS One hundred and fifty-four PSMA PET/MRI scans were available (133 [68Ga]Ga-PSMA-11 and 21 [18F]PSMA-1007). Significant cancer was present in 127 of them. The whole dataset was divided into a training cohort (n = 124) and a test cohort (n = 30). The C-ENet was able to predict the PSMA PET map with a dice similarity coefficient of 69.5 ± 15.6%. CONCLUSION Increased prostatic PSMA uptake on PET might be estimated based on T2 MRI alone. Further investigation with larger cohorts and external validation is needed to assess whether PSMA uptake can be predicted accurately enough to help in the interpretation of mpMRI.
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Waelti S, Skawran S, Sartoretti T, Schwyzer M, Gennari AG, Mader C, Treyer V, Kellenberger CJ, Burger IA, Hany T, Maurer A, Huellner MW, Messerli M. A third of the radiotracer dose: two decades of progress in pediatric [ 18F]fluorodeoxyglucose PET/CT and PET/MR imaging. Eur Radiol 2024; 34:3252-3259. [PMID: 37855853 PMCID: PMC11126459 DOI: 10.1007/s00330-023-10319-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 08/11/2023] [Accepted: 08/18/2023] [Indexed: 10/20/2023]
Abstract
OBJECTIVES To assess the evolution of administered radiotracer activity for F-18-fluorodeoxyglucose (18F-FDG) PET/CT or PET/MR in pediatric patients (0-16 years) between years 2000 and 2021. METHODS Pediatric patients (≤ 16 years) referred for 18F-FDG PET/CT or PET/MR imaging of the body during 2000 and 2021 were retrospectively included. The amount of administered radiotracer activity in megabecquerel (MBq) was recorded, and signal-to-noise ratio (SNR) was measured in the right liver lobe with a 4 cm3 volume of interest as an indicator for objective image quality. Descriptive statistics were computed. RESULTS Two hundred forty-three children and adolescents underwent a total of 466 examinations. The median injected 18F-FDG activity in MBq decreased significantly from 296 MBq in 2000-2005 to 100 MBq in 2016-2021 (p < 0.001), equaling approximately one-third of the initial amount. The median SNR ratio was stable during all years with 11.7 (interquartile range [IQR] 10.7-12.9, p = 0.133). CONCLUSIONS Children have benefited from a massive reduction in the administered 18F-FDG dose over the past 20 years without compromising objective image quality. CLINICAL RELEVANCE STATEMENT Radiotracer dose was reduced considerably over the past two decades of pediatric F-18-fluorodeoxyglucose PET/CT and PET/MR imaging highlighting the success of technical innovations in pediatric PET imaging. KEY POINTS • The evolution of administered radiotracer activity for F-18-fluorodeoxyglucose (18F-FDG) PET/CT or PET/MR in pediatric patients (0-16 years) between 2000 and 2021 was assessed. • The injected tracer activity decreased by 66% during the study period from 296 megabecquerel (MBq) to 100 MBq (p < 0.001). • The continuous implementation of technical innovations in pediatric hybrid 18F-FDG PET has led to a steady decrease in the amount of applied radiotracer, which is particularly beneficial for children who are more sensitive to radiation.
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Popescu CE, Zhang B, Sartoretti T, Spielhofer N, Skawran S, Heimer J, Messerli M, Sauter A, Huellner MW, Kaufmann PA, Burger IA, Maurer A. Evaluating the biodistribution for [ 68Ga]Ga-PSMA-11 and [ 18F]F-PSMA-1007 PET/CT with an inter- and intrapatient based analysis. EJNMMI Res 2024; 14:36. [PMID: 38578516 PMCID: PMC10997563 DOI: 10.1186/s13550-024-01097-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 03/15/2024] [Indexed: 04/06/2024] Open
Abstract
BACKGROUND Liver uptake in [68Ga]Ga-PSMA-11 PET is used as an internal reference in addition to clinical parameters to select patients for [177Lu]Lu-PSMA-617 radioligand therapy (RLT). Due to increased demand, [68Ga]Ga-PSMA-11 was replaced by [18F]F-PSMA-1007, a more lipophilic tracer with different biodistribution and splenic uptake was suggested as a new internal reference. We compared the intra-patient tracer distribution between [68Ga]Ga-PSMA-11 and [18F]F-PSMA-1007. METHODS Fifty patients who underwent PET examinations in two centers with both [18F]F-PSMA-1007 and [68Ga]Ga-PSMA-11 within one year were included. Mean standardized uptake values (SUVmean) were obtained for liver, spleen, salivary glands, blood pool, and bone. Primary tumor, local recurrence, lymph node, bone or visceral metastasis were also assessed for intra- and inter-individual comparison. RESULTS Liver SUVmean was significantly higher with [18F]F-PSMA-1007 (11.7 ± 3.9) compared to [68Ga]Ga-PSMA-11 (5.4 ± 1.7, p < .05) as well as splenic SUVmean (11.2 ± 3.5 vs.8.1 ± 3.5, p < .05). The blood pool was comparable between the two scans. Malignant lesions did not show higher SUVmean on [18F]F-PSMA-1007. Intra-individual comparison of liver uptake between the two scans showed a linear association for liver uptake with SUVmean [68Ga]Ga-PSMA-11 = 0.33 x SUVmean [18F]F-PSMA-1007 + 1.52 (r = .78, p < .001). CONCLUSION Comparing biodistribution of [68Ga]Ga and [18F]F tracers, liver uptake on [68Ga]Ga-PSMA-11 PET is the most robust internal reference value. Liver uptake of [18F]F-PSMA-1007 was significantly higher, but so was the splenic uptake. The strong intra-individual association of hepatic accumulation between the two scans may allow using of a conversion factor for [18F]F-PSMA-1007 as a basis for RLT selection.
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Sartoretti T, Skawran S, Gennari AG, Maurer A, Euler A, Treyer V, Sartoretti E, Waelti S, Schwyzer M, von Schulthess GK, Burger IA, Huellner MW, Messerli M. Fully automated computational measurement of noise in positron emission tomography. Eur Radiol 2024; 34:1716-1723. [PMID: 37644149 PMCID: PMC10873217 DOI: 10.1007/s00330-023-10056-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 04/15/2023] [Accepted: 05/15/2023] [Indexed: 08/31/2023]
Abstract
OBJECTIVES To introduce an automated computational algorithm that estimates the global noise level across the whole imaging volume of PET datasets. METHODS [18F]FDG PET images of 38 patients were reconstructed with simulated decreasing acquisition times (15-120 s) resulting in increasing noise levels, and with block sequential regularized expectation maximization with beta values of 450 and 600 (Q.Clear 450 and 600). One reader performed manual volume-of-interest (VOI) based noise measurements in liver and lung parenchyma and two readers graded subjective image quality as sufficient or insufficient. An automated computational noise measurement algorithm was developed and deployed on the whole imaging volume of each reconstruction, delivering a single value representing the global image noise (Global Noise Index, GNI). Manual noise measurement values and subjective image quality gradings were compared with the GNI. RESULTS Irrespective of the absolute noise values, there was no significant difference between the GNI and manual liver measurements in terms of the distribution of noise values (p = 0.84 for Q.Clear 450, and p = 0.51 for Q.Clear 600). The GNI showed a fair to moderately strong correlation with manual noise measurements in liver parenchyma (r = 0.6 in Q.Clear 450, r = 0.54 in Q.Clear 600, all p < 0.001), and a fair correlation with manual noise measurements in lung parenchyma (r = 0.52 in Q.Clear 450, r = 0.33 in Q.Clear 600, all p < 0.001). Classification performance of the GNI for subjective image quality was AUC 0.898 for Q.Clear 450 and 0.919 for Q.Clear 600. CONCLUSION An algorithm provides an accurate and meaningful estimation of the global noise level encountered in clinical PET imaging datasets. CLINICAL RELEVANCE STATEMENT An automated computational approach that measures the global noise level of PET imaging datasets may facilitate quality standardization and benchmarking of clinical PET imaging within and across institutions. KEY POINTS • Noise is an important quantitative marker that strongly impacts image quality of PET images. • An automated computational noise measurement algorithm provides an accurate and meaningful estimation of the global noise level encountered in clinical PET imaging datasets. • An automated computational approach that measures the global noise level of PET imaging datasets may facilitate quality standardization and benchmarking as well as protocol harmonization.
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Trachsel B, Imobersteg S, Valpreda G, Singer G, Grabherr R, Ormos M, Burger IA, Kubik-Huch RA, Schibli R, Vogel V, Béhé M. Relaxed fibronectin: a potential novel target for imaging endometriotic lesions. EJNMMI Res 2024; 14:17. [PMID: 38340184 DOI: 10.1186/s13550-024-01070-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Accepted: 01/24/2024] [Indexed: 02/12/2024] Open
Abstract
BACKGROUND Endometriosis is characterized by the ectopic occurrence of endometrial tissue. Though considered benign, endometriotic lesions possess tumor-like properties such as tissue invasion and remodeling of the extracellular matrix. One major clinical hurdle concerning endometriosis is its diagnosis. The diagnostic modalities ultrasound and MRI are often unable to detect all lesions, and a clear correlation between imaging and clinical symptoms is still controversial. Therefore, it was our aim to identify a potential target to image active endometriotic lesions. RESULTS For our studies, we employed the preclinical radiotracer [111In]In-FnBPA5, which specifically binds to relaxed fibronectin-an extracellular matrix protein with key functions in homeostasis that has been implicated in the pathogenesis of diseases such as cancer and fibrosis. We employed this tracer in biodistribution as well as SPECT/CT studies in mice and conducted immunohistochemical stainings on mouse uterine tissue as well as on patient-derived endometriosis tissue. In biodistribution and SPECT/CT studies using the radiotracer [111In]In-FnBPA5, we found that radiotracer uptake in the myometrium varies with the estrous cycle of the mouse, leading to higher uptake of [111In]In-FnBPA5 during estrogen-dependent phases, which indicates an increased abundance of relaxed fibronectin when estrogen levels are high. Finally, immunohistochemical analysis of patient samples demonstrated that there is preferential relaxation of fibronectin in the proximity of the endometriotic stroma. CONCLUSION Estrous cycle stages characterized by high estrogen levels result in a higher abundance of relaxed fibronectin in the murine myometrium. This finding together with a first proof-of-concept study employing human endometriosis tissues suggests that relaxed fibronectin could be a potential target for the development of a diagnostic radiotracer targeting endometriotic lesions. With [111In]In-FnBPA5, the matching targeting molecule is in preclinical development.
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Laudicella R, Bauckneht M, Burger IA. Is There a Role of Interim PSMA PET in Chemotherapy of Prostate Cancer? Semin Nucl Med 2024; 54:87-96. [PMID: 37599149 DOI: 10.1053/j.semnuclmed.2023.07.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 07/18/2023] [Accepted: 07/19/2023] [Indexed: 08/22/2023]
Abstract
While RECIST 1.1 is well established in radiological response assessment, it is of limited use in prostate cancer (PCa) considering that the disease is often seen only as sclerotic bone changes on conventional imaging. Therefore, a molecular imaging-based response assessment including bone scans has been proposed and used in clinical trials, however, due to the flare phenomenon on bone scans this assessment leads to substantial delays in the detection of progression. Indeed, a robust and reliable imaging tool to assess response to chemotherapy in PCa is still warranted. Whether Positron Emission Tomography (PET) targeting the Prostate-Specific Membrane Antigen (PSMA) could achieve this, is still controversial. In this review, we summarized the available data on cytotoxic agents and their impact on PSMA expression, as well as the available data on PSMA PET imaging for response assessment.
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Oprea-Lager DE, MacLennan S, Bjartell A, Briganti A, Burger IA, de Jong I, De Santis M, Eberlein U, Emmett L, Fizazi K, Gillessen S, Herrmann K, Heskamp S, Iagaru A, Jereczek-Fossa BA, Kunikowska J, Lam M, Nanni C, O'Sullivan JM, Panebianco V, Sala E, Sathekge M, Sosnowski R, Tilki D, Tombal B, Treglia G, Tunariu N, Walz J, Yakar D, Dierckx R, Sartor O, Fanti S. European Association of Nuclear Medicine Focus 5: Consensus on Molecular Imaging and Theranostics in Prostate Cancer. Eur Urol 2024; 85:49-60. [PMID: 37743194 DOI: 10.1016/j.eururo.2023.09.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 06/17/2023] [Accepted: 09/04/2023] [Indexed: 09/26/2023]
Abstract
BACKGROUND In prostate cancer (PCa), questions remain on indications for prostate-specific membrane antigen (PSMA) positron emission tomography (PET) imaging and PSMA radioligand therapy, integration of advanced imaging in nomogram-based decision-making, dosimetry, and development of new theranostic applications. OBJECTIVE We aimed to critically review developments in molecular hybrid imaging and systemic radioligand therapy, to reach a multidisciplinary consensus on the current state of the art in PCa. DESIGN, SETTING, AND PARTICIPANTS The results of a systematic literature search informed a two-round Delphi process with a panel of 28 PCa experts in medical or radiation oncology, urology, radiology, medical physics, and nuclear medicine. The results were discussed and ratified in a consensus meeting. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Forty-eight statements were scored on a Likert agreement scale and six as ranking options. Agreement statements were analysed using the RAND appropriateness method. Ranking statements were analysed using weighted summed scores. RESULTS AND LIMITATIONS After two Delphi rounds, there was consensus on 42/48 (87.5%) of the statements. The expert panel recommends PSMA PET to be used for staging the majority of patients with unfavourable intermediate and high risk, and for restaging of suspected recurrent PCa. There was consensus that oligometastatic disease should be defined as up to five metastases, even using advanced imaging modalities. The group agreed that [177Lu]Lu-PSMA should not be administered only after progression to cabazitaxel and that [223Ra]RaCl2 remains a valid therapeutic option in bone-only metastatic castration-resistant PCa. Uncertainty remains on various topics, including the need for concordant findings on both [18F]FDG and PSMA PET prior to [177Lu]Lu-PSMA therapy. CONCLUSIONS There was a high proportion of agreement among a panel of experts on the use of molecular imaging and theranostics in PCa. Although consensus statements cannot replace high-certainty evidence, these can aid in the interpretation and dissemination of best practice from centres of excellence to the wider clinical community. PATIENT SUMMARY There are situations when dealing with prostate cancer (PCa) where both the doctors who diagnose and track the disease development and response to treatment, and those who give treatments are unsure about what the best course of action is. Examples include what methods they should use to obtain images of the cancer and what to do when the cancer has returned or spread. We reviewed published research studies and provided a summary to a panel of experts in imaging and treating PCa. We also used the research summary to develop a questionnaire whereby we asked the experts to state whether or not they agreed with a list of statements. We used these results to provide guidance to other health care professionals on how best to image men with PCa and what treatments to give, when, and in what order, based on the information the images provide.
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Maurer A, Kotasidis F, Deibel A, Burger IA, Huellner MW. Whole-Body 18 F-FDG PET/CT Patlak Parametric Imaging of Hepatic Alveolar Echinococcosis. Clin Nucl Med 2023; 48:1089-1090. [PMID: 37801583 DOI: 10.1097/rlu.0000000000004878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/08/2023]
Abstract
ABSTRACT We present dynamic 18 F-FDG PET/CT acquisition in a 52-year-old old woman with histologically proven hepatic alveolar echinococcosis (AE). Metabolic rate of FDG images generated with traditional and relative Patlak analysis show the AE manifestation in the liver significantly better the static SUV images. Dynamic PET may thus have the potential to increase sensitivity in the assessment of hepatic AE manifestations. Such parametric images may offer complementary qualitative information and quantification superior to SUV images.
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Laudicella R, Bauckneht M, Maurer A, Heimer J, Gennari AG, Di Raimondo T, Paone G, Cuzzocrea M, Messerli M, Eberli D, Burger IA. Can We Predict Skeletal Lesion on Bone Scan Based on Quantitative PSMA PET/CT Features? Cancers (Basel) 2023; 15:5471. [PMID: 38001731 PMCID: PMC10670186 DOI: 10.3390/cancers15225471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 11/13/2023] [Accepted: 11/17/2023] [Indexed: 11/26/2023] Open
Abstract
OBJECTIVE The increasing use of PSMA-PET/CT for restaging prostate cancer (PCa) leads to a patient shift from a non-metastatic situation based on conventional imaging (CI) to a metastatic situation. Since established therapeutic pathways have been designed according to CI, it is unclear how this should be translated to the PSMA-PET/CT results. This study aimed to investigate whether PSMA-PET/CT and clinical parameters could predict the visibility of PSMA-positive lesions on a bone scan (BS). METHODS In four different centers, all PCa patients with BS and PSMA-PET/CT within 6 months without any change in therapy or significant disease progression were retrospectively selected. Up to 10 non-confluent clear bone metastases were selected per PSMA-PET/CT and SUVmax, SUVmean, PSMAtot, PSMAvol, density, diameter on CT, and presence of cortical erosion were collected. Clinical variables (age, PSA, Gleason Score) were also considered. Two experienced double-board physicians decided whether a bone metastasis was visible on the BS, with a consensus readout for discordant findings. For predictive performance, a random forest was fit on all available predictors, and its accuracy was assessed using 10-fold cross-validation performed 10 times. RESULTS A total of 43 patients were identified with 222 bone lesions on PSMA-PET/CT. A total of 129 (58.1%) lesions were visible on the BS. In the univariate analysis, all PSMA-PET/CT parameters were significantly associated with the visibility on the BS (p < 0.001). The random forest reached a mean accuracy of 77.6% in a 10-fold cross-validation. CONCLUSIONS These preliminary results indicate that there might be a way to predict the BS results based on PSMA-PET/CT, potentially improving the comparability between both examinations and supporting decisions for therapy selection.
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Albert NL, Garrigue P, Guillet B, Burger IA. Correction to: Highlights of the 35th EANM Annual Congress 2022, onsite edition in Barcelona, Spain: "FROM BARCELONA WITH LOVE". Eur J Nucl Med Mol Imaging 2023; 50:4114. [PMID: 37646835 DOI: 10.1007/s00259-023-06419-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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Champion A, Zwhalen DR, Oehler C, Taussky D, Kroeze SGC, Burger IA, Benzaquen D. Can PSMA PET/CT help in dose-tailoring in post-prostatectomy radiotherapy? Front Oncol 2023; 13:1268309. [PMID: 37799463 PMCID: PMC10548198 DOI: 10.3389/fonc.2023.1268309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 09/04/2023] [Indexed: 10/07/2023] Open
Abstract
There are few randomized trials to evaluate the use of PSMA-PET in the planning of post-prostatectomy radiotherapy. There are two unresolved questions 1) should we increase the dose to lesions visible on PSMA-PET 2) can we reduce dose in the case of a negative PSMA-PET. In this review, we summarize and discuss the available evidence in the literature. We found that in general, there seems to be an advantage for dose-increase, but ta large recent study from the pre-PSMA era didn't show an advantage for dose escalation. Retrospective studies have shown that conventional doses to PSMA-PET-positive lesions seem sufficient. On the other hand, in the case of a negative PSMA-PET, there is no evidence that dose-reduction is possible. In the future, the combination of PSMA-PET with genomic classifiers could help in better identify patients who might benefit from either dose- de-or -increase. We further need to identify intraindividual references to help identify lesions with higher aggressiveness.
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Albert NL, Garrigue P, Guillet B, Burger IA. Highlights of the 35th EANM Annual Congress 2022, onsite edition in Barcelona, Spain: "FROM BARCELONA WITH LOVE". Eur J Nucl Med Mol Imaging 2023; 50:3168-3176. [PMID: 37432447 DOI: 10.1007/s00259-023-06306-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/12/2023]
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Templeton AJ, Omlin A, Berthold D, Beyer J, Burger IA, Eberli D, Engeler D, Fankhauser C, Fischer S, Gillessen S, Nicolas G, Kroeze S, Lorch A, Müntener M, Papachristofilou A, Schaefer N, Seiler D, Stenner F, Tsantoulis P, Vlajnic T, Zilli T, Zwahlen D, Cathomas R. Interdisciplinary Swiss consensus recommendations on staging and treatment of advanced prostate cancer. Swiss Med Wkly 2023; 153:40108. [PMID: 37598311 DOI: 10.57187/smw.2023.40108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/21/2023] Open
Abstract
The management of prostate cancer is undergoing rapid changes in all disease settings. Novel imaging tools for diagnosis have been introduced, and the treatment of high-risk localized, locally advanced and metastatic disease has changed considerably in recent years. From clinical and health-economic perspectives, a rational and optimal use of the available options is of the utmost importance. While international guidelines list relevant pivotal trials and give recommendations for a variety of clinical scenarios, there is much room for interpretation, and several important questions remain highly debated. The goal of developing a national consensus on the use of these novel diagnostic and therapeutic strategies in order to improve disease management and eventually patient outcomes has prompted a Swiss consensus meeting. Experts from several specialties, including urology, medical oncology, radiation oncology, pathology and nuclear medicine, discussed and voted on questions of the current most important areas of uncertainty, including the staging and treatment of high-risk localized disease, treatment of metastatic hormone-sensitive prostate cancer (mHSPC) and use of new options to treat metastatic castration-resistant prostate cancer (mCRPC).
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Kuzmanov A, Salemi S, Schmid FA, Burger IA, Eberli D, Kranzbühler B. Improved Prostate-Specific Membrane Antigen (PSMA) Stimulation Using a Super Additive Effect of Dutasteride and Lovastatin In Vitro. Int J Mol Sci 2023; 24:12338. [PMID: 37569712 PMCID: PMC10419009 DOI: 10.3390/ijms241512338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 07/31/2023] [Accepted: 08/01/2023] [Indexed: 08/13/2023] Open
Abstract
Prostate-specific membrane antigen (PSMA)-based imaging improved the detection of primary, recurrent and metastatic prostate cancer. However, in certain patients, a low PSMA surface expression can be a limitation for this promising diagnostic tool. Pharmacological induction of PSMA might be useful to further improve the detection rate of PSMA-based imaging. To achieve this, we tested dutasteride (Duta)-generally used for treatment of benign prostatic enlargement-and lovastatin (Lova)-a compound used to reduce blood lipid concentrations. We aimed to compare the individual effects of Duta and Lova on cell proliferation as well as PSMA expression. In addition, we tested if a combination treatment using lower concentrations of Duta and Lova can further induce PSMA expression. Our results show that a treatment with ≤1 μM Duta and ≥1 μM Lova lead to a significant upregulation of whole and cell surface PSMA expression in LNCaP, C4-2 and VCaP cells. Lower concentrations of Duta and Lova in combination (0.5 μM Duta + 0.5 μM Lova or 0.5 μM Duta + 1 μM Lova) were further capable of enhancing PSMA protein expression compared to a single compound treatment using higher concentrations in all tested cell lines (LNCaP, C4-2 and VCaP).
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Muehlematter UJ, Schweiger L, Ferraro DA, Hermanns T, Maurer T, Heck MM, Rupp NJ, Eiber M, Rauscher I, Burger IA. Development and external validation of a multivariable [ 68Ga]Ga-PSMA-11 PET-based prediction model for lymph node involvement in men with intermediate or high-risk prostate cancer. Eur J Nucl Med Mol Imaging 2023; 50:3137-3146. [PMID: 37261472 PMCID: PMC10382335 DOI: 10.1007/s00259-023-06278-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 05/19/2023] [Indexed: 06/02/2023]
Abstract
PURPOSE To develop and evaluate a lymph node invasion (LNI) prediction model for men staged with [68Ga]Ga-PSMA-11 PET. METHODS A consecutive sample of intermediate to high-risk prostate cancer (PCa) patients undergoing [68Ga]Ga-PSMA-11 PET, extended pelvic lymph node dissection (ePLND), and radical prostatectomy (RP) at two tertiary referral centers were retrospectively identified. The training cohort comprised 173 patients (treated between 2013 and 2017), the validation cohort 90 patients (treated between 2016 and 2019). Three models for LNI prediction were developed and evaluated using cross-validation. Optimal risk-threshold was determined during model development. The best performing model was evaluated and compared to available conventional and multiparametric magnetic resonance imaging (mpMRI)-based prediction models using area under the receiver operating characteristic curves (AUC), calibration plots, and decision curve analysis (DCA). RESULTS A combined model including prostate-specific antigen, biopsy Gleason grade group, [68Ga]Ga Ga-PSMA-11 positive volume of the primary tumor, and the assessment of the [68Ga]Ga-PSMA-11 report N-status yielded an AUC of 0.923 (95% CI 0.863-0.984) in the external validation. Using a cutoff of ≥ 17%, 44 (50%) ePLNDs would be spared and LNI missed in one patient (4.8%). Compared to conventional and MRI-based models, the proposed model showed similar calibration, higher AUC (0.923 (95% CI 0.863-0.984) vs. 0.700 (95% CI 0.548-0.852)-0.824 (95% CI 0.710-0.938)) and higher net benefit at DCA. CONCLUSIONS Our results indicate that information from [68Ga]Ga-PSMA-11 may improve LNI prediction in intermediate to high-risk PCa patients undergoing primary staging especially when combined with clinical parameters. For better LNI prediction, future research should investigate the combination of information from both PSMA PET and mpMRI for LNI prediction in PCa patients before RP.
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Hotta M, Gafita A, Murthy V, Benz MR, Sonni I, Burger IA, Eiber M, Emmett L, Farolfi A, Fendler WP, Weber MM, Hofman MS, Hope TA, Kratochwil C, Czernin J, Calais J. PSMA PET Tumor-to-Salivary Gland Ratio to Predict Response to [ 177Lu]PSMA Radioligand Therapy: An International Multicenter Retrospective Study. J Nucl Med 2023; 64:1024-1029. [PMID: 36997329 DOI: 10.2967/jnumed.122.265242] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 02/10/2023] [Accepted: 02/10/2023] [Indexed: 04/01/2023] Open
Abstract
Prostate-specific membrane antigen (PSMA)-targeted radioligand therapy can improve the outcome of patients with advanced metastatic castration-resistant prostate cancer, but patients do not respond uniformly. We hypothesized that using the salivary glands as a reference organ can enable selective patient stratification. We aimed to establish a PSMA PET tumor-to-salivary gland ratio (PSG score) to predict outcomes after [177Lu]PSMA. Methods: In total, 237 men with metastatic castration-resistant prostate cancer treated with [177Lu]PSMA were included. A quantitative PSG (qPSG) score (SUVmean ratio of whole-body tumor to parotid glands) was semiautomatically calculated on baseline [68Ga]PSMA-11 PET images. Patients were divided into 3 groups: high (qPSG > 1.5), intermediate (qPSG = 0.5-1.5), and low (qPSG < 0.5) scores. Ten readers interpreted the 3-dimensional maximum-intensity-projection baseline [68Ga]PSMA-11 PET images and classified patients into 3 groups based on visual PSG (vPSG) score: high (most of the lesions showed higher uptake than the parotid glands) intermediate (neither low nor high), and low (most of the lesions showed lower uptake than the parotid glands). Outcome data included a more than 50% prostate-specific antigen decline, prostate-specific antigen (PSA) progression-free survival, and overall survival (OS). Results: Of the 237 patients, the numbers in the high, intermediate, and low groups were 56 (23.6%), 163 (68.8%), and 18 (7.6%), respectively, for qPSG score and 106 (44.7%), 96 (40.5%), and 35 (14.8%), respectively, for vPSG score. The interreader reproducibility of the vPSG score was substantial (Fleiss weighted κ, 0.68). The more than 50% prostate-specific antigen decline was better in patients with a higher PSG score (high vs. intermediate vs. low, 69.6% vs. 38.7% vs. 16.7%, respectively, for qPSG [P < 0.001] and 63.2% vs 33.3% vs 16.1%, respectively, for vPSG [P < 0.001]). The median PSA progression-free survival of the high, intermediate, and low groups by qPSG score was 7.2, 4.0, and 1.9 mo (P < 0.001), respectively, by qPSG score and 6.7, 3.8, and 1.9 mo (P < 0.001), respectively, by vPSG score. The median OS of the high, intermediate, and low groups was 15.0, 11.2, and 13.9 mo (P = 0.017), respectively, by qPSG score and 14.3, 9.6, and 12.9 mo (P = 0.018), respectively, by vPSG score. Conclusion: The PSG score was prognostic for PSA response and OS after [177Lu]PSMA. The visual PSG score assessed on 3-dimensional maximum-intensity-projection PET images yielded substantial reproducibility and comparable prognostic value to the quantitative score.
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Girard N, Ponce Aix S, Cedres S, Berghmans T, Burgers S, Toffart AC, Popat S, Janssens A, Gervais R, Hochstenbag M, Silva M, Burger IA, Prosch H, Stahel R, Xenophontos E, Pretzenbaher Y, Neven A, Peters S. Efficacy and safety of nivolumab for patients with pre-treated type B3 thymoma and thymic carcinoma: results from the EORTC-ETOP NIVOTHYM phase II trial. ESMO Open 2023; 8:101576. [PMID: 37285717 DOI: 10.1016/j.esmoop.2023.101576] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 04/07/2023] [Accepted: 04/24/2023] [Indexed: 06/09/2023] Open
Abstract
BACKGROUND Thymic malignancies are rare intrathoracic tumors, which may be aggressive and difficult to treat. They represent a therapeutic challenge in the advanced/metastatic setting, with limited treatment options after the failure of first-line platinum-based chemotherapy. They are frequently associated with autoimmune disorders that also impact oncological management. MATERIALS AND METHODS NIVOTHYM is an international, multicenter, phase II, two-cohort, single-arm trial evaluating the activity and safety of nivolumab [240 mg intravenously (i.v.) q2 weeks] alone or with ipilimumab (1 mg /kg i.v. q6 weeks) in patients with advanced/relapsed type B3 thymoma or thymic carcinoma, after exposure to platinum-based chemotherapy. The primary endpoint is progression-free survival rate at 6 months (PFSR-6) based on RECIST 1.1 as per independent radiological review. RESULTS From April 2018 to February 2020, 55 patients were enrolled in 15 centers from 5 countries. Ten patients (18%) had type B3 thymoma and 43 (78%) had thymic carcinoma. The majority were male (64%), and the median age was 58 years. Among the 49 eligible patients who started treatment, PFSR-6 by central review was 35% [95% confidence interval (CI) 22% to 50%]. The overall response rate and disease control rate were 12% (95% CI 5% to 25%) and 63% (95% CI 48% to 77%), respectively. Using the Kaplan-Meier method, median progression-free survival and overall survival by local assessment were 6.0 (95% CI 3.1-10.4) months and 21.3 (95% CI 11.6-not estimable) months, respectively. In the safety population of 54 patients, adverse events (AEs) of grade 1/2 were observed in 22 (41%) patients and grade 3/4 in 31 (57%) patients. Treatment-related AEs of grade 4 included one case of neutropenia, one case of immune-mediated transaminitis, and two cases of myocarditis. CONCLUSIONS Nivolumab monotherapy demonstrated an acceptable safety profile and objective activity, although it has been insufficient to meet its primary objective. The second cohort of NIVOTHYM is currently ongoing to assess the combination of nivolumab plus ipilimumab.
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Laudicella R, Spataro A, Crocè L, Giacoppo G, Romano D, Davì V, Lopes M, Librando M, Nicocia A, Rappazzo A, Celesti G, Torre FL, Pagano B, Garraffa G, Bauckneht M, Burger IA, Minutoli F, Baldari S. Preliminary Findings of the Role of FAPi in Prostate Cancer Theranostics. Diagnostics (Basel) 2023; 13:diagnostics13061175. [PMID: 36980482 PMCID: PMC10047910 DOI: 10.3390/diagnostics13061175] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 03/15/2023] [Accepted: 03/17/2023] [Indexed: 03/22/2023] Open
Abstract
Prostate cancer (PCa) is the most frequently diagnosed cancer worldwide and the second most common cause of cancer-related deaths among men. Progress in molecular imaging has magnified its clinical management; however, an unmet clinical need involves the identification of new imaging biomarkers that complement the gold standard of prostate-specific membrane antigen (PSMA) positron emission tomography (PET) in cases of clinically significant PCa that do not express PSMA. Fibroblast activation protein (FAP) is a type II transmembrane serine overexpressed in many solid cancers that can be imaged through quinoline-based PET tracers derived from an FAP inhibitor (FAPi). Preliminary results of FAPi application in PCa (in PSMA-negative lesions, and in comparison with fluorodeoxyglucose—FDG) are now available in the literature. FAP-targeting ligands for PCa are not limited to detection, but could also include therapeutic applications. In this preliminary review, we provide an overview of the clinical applications of FAPi ligands in PCa, summarising the main results and highlighting contemporary strengths and limitations.
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Bauckneht M, Miceli A, Signori A, Albano D, Capitanio S, Piva R, Laudicella R, Franchini A, D'Amico F, Riondato M, Chiola S, Marini C, Fornarini G, Scarale A, Muni A, Bertagna F, Burger IA, Sambuceti G, Morbelli S. Combined forced diuresis and late acquisition on [ 68Ga]Ga-PSMA-11 PET/CT for biochemical recurrent prostate cancer: a clinical practice-oriented study. Eur Radiol 2023; 33:3343-3353. [PMID: 36892650 PMCID: PMC10121525 DOI: 10.1007/s00330-023-09516-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 12/22/2022] [Accepted: 02/03/2023] [Indexed: 03/10/2023]
Abstract
OBJECTIVES Increased detection of prostate cancer (PCa) recurrences using [68Ga]Ga-PSMA-11 PET/CT has been reported by adding forced diuresis or late-phase imaging to the standard protocol. However, the combination of these procedures in the clinical setting is still not standardized. METHODS One hundred prospectively recruited biochemical recurrent PCa patients were restaged with dual-phase [68Ga]Ga-PSMA-11 PET/CT from September 2020 to October 2021. All patients received a standard scan (60 min), followed by diuretics (140 min) and a late-phase abdominopelvic scan (180 min). PET readers with low (n = 2), intermediate (n = 2), or high (n = 2) experience rated (i) standard and (ii) standard + forced diuresis late-phase images in a stepwise fashion according to E-PSMA guidelines, scoring their level of confidence. Study endpoints were (i) accuracy against a composite reference standard, (ii) reader's confidence level, and (iii) interobserver agreement. RESULTS Forced diuresis late-phase imaging increased the reader's confidence category for local and nodal restaging (both p < 0.0001), and the interobserver agreement in identifying nodal recurrences (from moderate to substantial, p < 0.01). However, it significantly increased diagnostic accuracy exclusively for local uptakes rated by low-experienced readers (from 76.5 to 84%, p = 0.05) and for nodal uptakes rated as uncertain at standard imaging (from 68.1 to 78.5%, p < 0.05). In this framework, SUVmax kinetics resulted in an independent predictor of PCa recurrence compared to standard metrics, potentially guiding the dual-phase PET/CT interpretation. CONCLUSIONS The present results do not support the systematic combination of forced diuresis and late-phase imaging in the clinical setting, but allow the identification of patients-, lesions-, and reader-based scenarios that might benefit from it. KEY POINTS • Increased detection of prostate cancer recurrences has been reported by adding diuretics administration or an additional late abdominopelvic scan to the standard [68Ga]Ga-PSMA-11 PET/CT procedure. • We verified the added value of combined forced diuresis and delayed imaging, showing that this protocol only slightly increases the diagnostic accuracy of [68Ga]Ga-PSMA-11 PET/CT, thus not justifying its systematic use in clinics. • However, it can be helpful in specific clinical scenarios, e.g., when PET/CT is reported by low-experienced readers. Moreover, it increased the reader's confidence and the agreement among observers.
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Twyman R, Arridge S, Kereta Z, Jin B, Brusaferri L, Ahn S, Stearns CW, Hutton BF, Burger IA, Kotasidis F, Thielemans K. An Investigation of Stochastic Variance Reduction Algorithms for Relative Difference Penalized 3D PET Image Reconstruction. IEEE TRANSACTIONS ON MEDICAL IMAGING 2023; 42:29-41. [PMID: 36044488 DOI: 10.1109/tmi.2022.3203237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Penalised PET image reconstruction algorithms are often accelerated during early iterations with the use of subsets. However, these methods may exhibit limit cycle behaviour at later iterations due to variations between subsets. Desirable converged images can be achieved for a subclass of these algorithms via the implementation of a relaxed step size sequence, but the heuristic selection of parameters will impact the quality of the image sequence and algorithm convergence rates. In this work, we demonstrate the adaption and application of a class of stochastic variance reduction gradient algorithms for PET image reconstruction using the relative difference penalty and numerically compare convergence performance to BSREM. The two investigated algorithms are: SAGA and SVRG. These algorithms require the retention in memory of recently computed subset gradients, which are utilised in subsequent updates. We present several numerical studies based on Monte Carlo simulated data and a patient data set for fully 3D PET acquisitions. The impact of the number of subsets, different preconditioners and step size methods on the convergence of regions of interest values within the reconstructed images is explored. We observe that when using constant preconditioning, SAGA and SVRG demonstrate reduced variations in voxel values between subsequent updates and are less reliant on step size hyper-parameter selection than BSREM reconstructions. Furthermore, SAGA and SVRG can converge significantly faster to the penalised maximum likelihood solution than BSREM, particularly in low count data.
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