68Ga-PSMA-11 PET/CT-derived metabolic parameters for determination of whole-body tumor burden and treatment response in prostate cancer (original) (raw)
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Journal of Clinical Medicine, 2020
(1) Background: Prostate-specific membrane antigen (PSMA)-derived tumour volume (PSMA-TV) and total lesion PSMA (TL-PSMA) from PSMA PET/CT scans are promising biomarkers for assessing treatment response in prostate cancer (PCa). Currently, it is unclear whether different software tools for assessing PSMA-TV and TL-PSMA produce comparable results. (2) Methods: 68 Ga-PSMA PET/CT scans from n = 21 patients with castration-resistant PCa (CRPC) receiving chemotherapy were identified from our single-centre database. PSMA-TV and TL-PSMA were calculated with Syngo.via (Siemens) as well as the freely available Beth Israel plugin for FIJI (Fiji Is Just ImageJ) before and after chemotherapy. While statistical comparability was illustrated and quantified via Bland-Altman diagrams, the clinical agreement was estimated by matching PSMA-TV, TL-PSMA and relative changes of both variables during chemotherapy with changes in serum PSA (∆PSA) and PERCIST (Positron Emission Response Criteria in Solid Tumors). (3) Results: Comparing absolute PSMA-TV and TL-PSMA as well as Bland-Altman plotting revealed a good statistical comparability of both software algorithms. For clinical agreement, classifying therapy response did not differ between PSMA-TV and TL-PSMA for both software solutions and showed highly positive correlations with BR. (4) Conclusions: due to the high levels of statistical and clinical agreement in our CRPC patient cohort undergoing taxane chemotherapy, comparing PSMA-TV and TL-PSMA determined by Syngo.via and FIJI appears feasible.
Systemic therapy response evaluation in prostate carcinoma with [68Ga]Ga-PSMA-11 PET/CT
Egyptian Journal of Radiology and Nuclear Medicine
Background Consensus statements was published by EAU and EANM to clarify some uncertainties on PSMA PET/CT response assessment in 2020. We aimed to investigate the response criteria for PSMA PET/CT according to published criteria by comparing with serum PSA changes and determine the factors affecting therapy response evaluation. Results A high concordance was found between [68Ga]Ga-PSMA-11 PET/CT and serum PSA responses and 0.84 of Gamma coefficient was obtained. Between concordant and discordant group, statistically significant difference was not found in terms of received therapies and castration resistance status. Statistically significant but low correlation was found between serum PSA and SUV values of prostate, moderate correlation was found serum PSA and SUVmax values of metastatic lymph nodes and bones. Conclusions The response evaluation of PSMA PET/CT according to the published criteria shows high concordance with serum PSA values without being affected by received therapi...
Scripta Scientifica Medica, 2022
INTRODUCTION: Currently 68 Ga-PSMA PET/CT is making a significant shift in the diagnosis, staging and restaging of prostate cancer (PC) patients. Мany questions have been raised concerning the indications and the sensitivity of the method. Most of them are related to the PSA values in biochemical progression, specifically in the low PSA values of up to 2.00 ng/mL. AIM: The aim of this study was to analyze the influence of PSA values in biochemical progression on 68 Ga-PSMA PET/CT sensitivity, detection rate and the association with regional or metastatic lesions incidence in patients after radical prostatectomy (RP) with a focus on the impact of the lower ranges of the PSA values. MATERIAL AND METHODS: We performed a retrospective analysis in 144 consecutive patients with radical prostatectomy (RP) who underwent 68 Ga-PSMA PET/CT from July 2019 to February 2020. The patients were divided into six groups according to the PSA value: 1) ≤0.040 ng/mL; 2) 0.041-0.160 ng/mL; 3) 0.161-0.500 ng/mL; 4) 0.501-1.0 ng/mL; 5) 1.001-2.00 ng/mL; 6) >2.00 ng/mL. RESULTS AND DISCUSSION: The mean age of the patients was 67.3 (7) years and the mean PSA level was 11.0 (52.28) ng/mL. A total of 62 patients (43.1%) showed at least one positive lesion. 68 Ga-PSMA PET/CT detection rate varied into the different groups between 12.0% and 94.0%. There was a significant relationship between the PSA level and the ability of 68 Ga-PSMA PET/CT to detect the lesions. Local recurrence was determined in patients with higher PSA values. Regional metastatic lymph nodes incidence in the 6 groups was between 17.0% and 50.0%. Bone metastases were most commonly diagnosed in patients with low PSA levels. Distant lymph nodes involvement in the studied groups ranged between 0.0% and 75.0%. Distant metastases were detected most commonly in patients with low levels of PSA. The PSA-based assessment of the overall sensitivity and specificity of 68 Ga-PSMA PET/CT was
Positron Emission Tomography (PET) in Oncology
Cancers, 2014
Since its introduction in the early nineties as a promising functional imaging technique in the management of neoplastic disorders, FDG-PET, and subsequently FDG-PET/CT, has become a cornerstone in several oncologic procedures such as tumor staging and restaging, treatment efficacy assessment during or after treatment end and radiotherapy planning. Moreover, the continuous technological progress of image generation and the introduction of sophisticated software to use PET scan as a biomarker paved the way to calculate new prognostic markers such as the metabolic tumor volume (MTV) and the total amount of tumor glycolysis (TLG). FDG-PET/CT proved more sensitive than contrast-enhanced CT scan in staging of several type of lymphoma or in detecting widespread tumor dissemination in several solid cancers, such as breast, lung, colon, ovary and head and neck carcinoma. As a consequence the stage of patients was upgraded, with a change of treatment in 10%-15% of them. One of the most evident advantages of FDG-PET was its ability to detect, very early during treatment, significant changes in glucose metabolism or even complete shutoff of the neoplastic cell metabolism as a surrogate of tumor chemosensitivity assessment. This could enable clinicians to detect much earlier the effectiveness of a given antineoplastic treatment, as compared to the traditional radiological detection of tumor shrinkage, which usually takes time and occurs much later.
2020
The study aimed to evaluate the effect of androgen deprivation therapy (ADT) on PSMA imaging and its correlation to the PSA concentration by comparing qualitative and quantitative parameters: SUV max , SUV mean , PSMA-derived tumor volume (PSMA-TV), total lesion PSMA (TL-PSMA) and molecular imaging (mi)PSMA score. Methods: Retrospective analysis of 21 therapy-naïve patients with oligometastatic prostate cancer (median age 70 years) who underwent either [ 68 Ga]Ga-PSMA-11-PET/CT or-PET/MRI before initiation of (T1) as well as during ADT (T2). The median duration of ADT was 155 days (range: 61-289 days). All lesions were analyzed using several qualitative and quantitative PET parameters. Results: A total of 109 PSMA-positive lesions (24 intraprostatic, 56 lymphonodal, and 29 osseous) were visually detected at any of the examinations, while at T2, two new bone lesions were detected in one patient. During ADT, all patients experienced a decrease in their PSA level (median: 29.1 before vs. 0.71 after; p<0.001). During long-term ADT, a relevant decrease in lesion count occurred, especially in patients with a T2 PSA value < 1 ng/ml (median: 4 vs. 0.9; p=0.007) and PSMA expression, which resulted in miN-and/or miM-downstaging in 11 patients (52.7%). All analyzed PET parameters correlated strongly with each other. The PSA level at T2 correlated modestly with the decrease in PSMA expression and its derived volumes. Conclusion: Post-ADT scans detected, especially in patients with a residual PSA < 1 ng/ml, fewer PSMA-positive lesions with overall lower PSMA expression, regardless of primary tumor site or metastatic sites. None of the PET parameters has proven to be superior, as they all correlated modestly with the PSA value at T2. Thus, the simply acquirable miPSMA score seems to be the most suitable for evaluating the effect of ADT on PSMA expression.
European Journal of Nuclear Medicine and Molecular Imaging, 2019
Objectives Aim of the present analysis is to investigate the biodistribution and pharmacokinetics of the recently clinically introduced radioligand 18 F-PSMA-1007 in patients with biochemical recurrence or progression of prostate cancer (PC) by means of multiparametric (dynamic and whole-body) PET/CT. Methods Twenty-five (25) patients with PC biochemical relapse or progression (median age = 66.0 years) were enrolled in the analysis. The median PSA value was 1.2 ng/mL (range = 0.1-237.3 ng/mL) and the median Gleason score was 7 (range = 6-10). All patients underwent dynamic PET/CT (dPET/CT) scanning (60 min) of the pelvis and lower abdomen as well as whole-body PET/CT with 18 F-PSMA-1007. PET/CT assessment was based on qualitative evaluation, SUV calculation, and quantitative analysis based on a two-tissue compartment model and fractal analysis. Results 15/25 patients were PET-positive. Plasma PSA values in the 18 F-PSMA-1007 positive group were higher (median = 3.6 ng/mL; range = 0.2-237.3 ng/mL) than in the 18 F-PSMA-1007 negative group (median value = 0.7 ng/mL; range = 0.1-3.0 ng/mL). Semi-quantitative analysis in the PC lesions demonstrated a mean SUV average = 25.1 (median = 15.4; range = 3.5-119.2) and a mean SUV max = 41.5 (median = 25.7; range = 3.8-213.2). Time-activity curves derived from dPET/CT revealed an increasing tracer accumulation during the 60 min of dynamic PET acquisition into the PC lesions, higher than in the urinary bladder and the colon. Significant correlations were observed between 18 F-PSMA-1007 uptake (SUV), influx, and fractal dimension (FD). Conclusions 18 F-PSMA-1007 PET/CT could detect PC lesions in 60% of the patients of a mixed population, including also patients with very low PSA values. Higher PSA values were associated with a higher detection rate. Dynamic PET analysis revealed an increasing tracer uptake during the dynamic PET acquisition as well as high binding and internalization of the radiofluorinated PSMA ligand in the PC lesions.
Journal of Nuclear Medicine, 2020
Bone is the most common site of distant metastatic spread in prostate adenocarcinoma. Prostatespecific membrane antigen uptake has been described in both benign and malignant bone lesions, which can lead to false-positive findings on 68 Ga-prostate-specific membrane antigen-11 positron emission tomography (68 Ga-PSMA-11 PET). The purpose of this study was to evaluate the diagnostic accuracy of 68 Ga-PSMA-11 PET for osseous prostate cancer metastases and improve bone uptake interpretation using semi-quantitative metrics. METHODS. 56 prostate cancer patients (18 pre-prostatectomy, 38 biochemical recurrence) who underwent 68 Ga-PSMA-11 PET/MRI or PET/CT examinations with osseous PSMA-ligand uptake were included in the study. Medical records were reviewed retrospectively by boardcertified nuclear radiologists to determine true or false positivity based on a composite endpoint. For each avid osseous lesion, biological volume, size, PSMA-RADS rating, maximum standardized uptake value (SUVmax), and ratio of lesion SUVmax to liver, blood pool, and background bone SUVmax were measured. Differences between benign and malignant lesions were evaluated for statistical significance, and cutoff values for these parameters were determined to maximize diagnostic accuracy. RESULTS. Among 56 participants, 13 patients (22.8%) had false-positive osseous 68 Ga-PSMA-11 findings and 43 patients (76.8%) had true-positive osseous 68 Ga-PSMA-11 findings. Twentytwo patients (39%) had 1 osseous lesion, 18 (32%) had 2-4 lesions, and 16 (29%) had 5 or more lesions. Cutoff values resulting in statistically significant (p<0.005) differences between benign and malignant lesions were: PSMA-RADS ≥4, SUVmax ≥4.1, SUVmax ratio of lesion to blood pool ≥2.11, to liver ≥0.55, and to bone ≥4.4. These measurements corresponded to lesion-based 68 Ga-PSMA-11 PET lesion detection rate for malignancy of 80%, 93%, 89%, 21%, 89%, and a specificity of 73%, 73%, 73%, 93%, 60%, respectively. CONCLUSION. PSMA-RADS rating, SUVmax, and SUVmax ratio of lesion to blood pool can help differentiate benign from malignant lesions on 68 Ga-PSMA-11 PET. SUVmax ratio to blood pool above 2.2 is a reasonable parameter to support image interpretation and presented superior lesion detection rate and specificity when compared to visual interpretation by PSMA RADS. These parameters hold clinical value by improving diagnostic accuracy for metastatic prostate cancer on 68 Ga-PSMA-11 PET/MRI and PET/CT.
68Ga-PSMA-11 Dynamic PET/CT Imaging in Primary Prostate Cancer
Clinical Nuclear Medicine, 2016
The aim of our study is to assess the pharmacokinetics and biodistribution of 68 Ga-PSMA-11 in patients suffering from primary prostate cancer (PC) by means of dynamic and whole-body PET/CT. Materials and methods: Twenty-four patients with primary, previously untreated PC were enrolled in the study. All patients underwent dynamic PET/ CT (dPET/CT) scanning of the pelvis and whole-body PET/CT studies with 68 Ga-PSMA-11. The evaluation of dPET/CT studies was based on qualitative evaluation, SUV calculation, and quantitative analysis based on two-tissue compartment modeling and a noncompartmental approach leading to the extraction of fractal dimension (FD). Results: A total of 23/24 patients (95.8%) were 68 Ga-PSMA-11 positive. In 9/24 patients (37.5%), metastatic lesions were detected. PC-associated lesions demonstrated the following mean values: SUV average = 14.3, SUV max = 23.4, K 1 = 0.24 (1/min), k 3 = 0.34 (1/min), influx = 0.15 (1/ min), and FD = 1.27. The parameters SUV average , SUV max , k 3 , influx, and FD derived from PC-associated lesions were significantly higher than respective values derived from reference prostate tissue. Time-activity curves derived from PC-associated lesions revealed an increasing 68 Ga-PSMA-11 accumulation during dynamic PET acquisition. Correlation analysis revealed a moderate but significant correlation between PSA levels and SUV average (r = 0.60) and SUV max (r = 0.57), and a weak but significant correlation between Gleason score and SUV average (r = 0.33) and SUV max (r = 0.28). Conclusion: 68 Ga-PSMA-11 PET/CT confirmed its capacity in detecting primary PC with a detection rate of 95.8%. Dynamic PET/CT studies of the pelvis revealed an increase in tracer uptake in PC-associated lesions during the 60 minutes of dynamic PET acquisition, a finding with potential applications in anti-PSMA approaches.
Repeatability of 68Ga-PSMA-HBED-CC PET/CT-derived total molecular tumor volume
Journal of Nuclear Medicine, 2021
Background Molecular tumor volume (MTV) is a parameter of interest in advanced prostate cancer for assessing total disease burden on prostate-specific membrane antigen (PSMA) PET. Although software segmentation tools can delineate whole-body MTV, a necessary step towards meaningful monitoring of total tumor burden and treatment response through PET is establishing the repeatability of these metrics. The present study assesses the repeatability of total MTV and related metrics for 68 Ga-PSMA-HBED-CC in advanced prostate cancer. Methods Eighteen patients from a prior repeatability study who underwent two test-retest PSMA PET/CT scans within a mean interval of 5 days were reanalyzed. Within subject coefficient of variation and repeatability coefficients (RC) were analyzed on a per lesion and per patient basis. For the per lesion analysis, individual lesions were segmented for analysis by a single reader. For per patient analysis, subgroups of up to 10 lesions (single reader) and the total tumor volume per patient were segmented (independently by two readers). Image parameters were: MTV; maximum, peak, and mean standardized uptake value; total lesion PSMA and the related metric PSMA quotient (which is integrating lesion volume and PSMA avidity). Results In total, 192 segmentations were analyzed for the per lesion analysis and 1662 segmentations for the total tumor volume per patient analysis (combining the 2 readers and 2 scans). The RC of the MTV of single lesions was 77% (95%CI:63-96%). The RC improved after aggregation of up to 10 manually selected lesions into subgroups assessed per patient, 33% (95%CI:25-46%). The RC of 3 the semi-automatic MTVtotal was 35% (95%CI:25-50), the bland-altman bias was-6.70 [95%CI:-14.32-0.93]. Alternating readers between scans led to a comparable RC of 37% (95%CI:28-49%) for MTVtotal meaning that the metric is robust between scanning sessions and between readers. Conclusion 68 Ga-PSMA-HBED-CC PET-derived semi-automatic MTVtotal is repeatable and reader independent with a change of ±35% representing a true change in tumor volume. Volumetry of single manually selected lesions has considerably lower repeatability, and volumetry based on subgroups of these lesions, while showing acceptable repeatability, is less systematic. The semiautomatic analysis of MTVtotal employed in this study offers an efficient and robust means of assessing response to therapy.