Preoperative PET Research Articles

Detection of Apical Cancer with Novel Imaging Modalities to Predict Apical Margin Positivity in Robotic Assisted Radical Prostatectomy

ObjectivesTo evaluate margin positivity at apex utilizing preoperative magnetic resonance imaging [MRI], micro-ultrasound [MUS], prostate specific membrane antigen positron emission tomography PSMA PET] scan, biopsy location and intraoperative timing of deep venous complex [DVC] ligation during robot assisted radical prostatectomy [RARP]. MethodsInstitution review board approved retrospective study underwent RARP between November 2022 to March 2024. All patients underwent preoperative MRI, MUS and PSMA PET scan. Patients underwent RARP using either standard DVC [done prior apical dissection] ligation or delayed DVC [after prostate removal] technique. All patients underwent intra operative frozen section analysis by an experienced genitourinary pathologist. Descriptive statistics were performed. Data analyzed using R software version 4.3.3. ResultsTotal 619 prostate cancer patients underwent RARP. Of these, 365 men underwent RARP using delayed DVC ligation technique and 254 men using standard DVC ligation technique. There was no statically significant difference in two groups on demographic parameters, MRI, MUS and PSMA-PET scan features. Sensitivity of MRI, MUS, PSMA-PET and prostate biopsy for detection of apical positive margin were 66%, 81%, 81% and 73% respectively. Specificity of MRI, MUS, PSMA-PET and prostate biopsy for detection of apical positive margin were 45%, 14%, 16% and 30% respectively. When all modalities are used accumulatively, apical cancer was missed only in 1% of cases. ConclusionsWith proper preoperative understanding of apical lesion location, timing of DVC ligation [standard vs delayed] doesn't impact apical positive surgical margins. Combination of MRI, MUS, PSMA-PET and prostate biopsy reduce apical positive surgical margin rates significantly.

The association of quantitative PSMA PET parameters with pathologic ISUP grade: an international multicenter analysis.

To assess if PSMA PET quantitative parameters are associated with pathologic ISUP grade group (GG) and upgrading/downgrading. PCa patients undergoing radical prostatectomy with or without pelvic lymph node dissection staged with preoperative PSMA PET at seven referral centres worldwide were evaluated. PSMA PET parameters which included SUVmax, PSMAvolume, and total PSMA accumulation (PSMAtotal) were collected. Multivariable logistic regression evaluated the association between PSMA PET quantified parameters and surgical ISUP GG. Decision-tree analysis was performed to identify discriminative thresholds for all three parameters related to the five ISUP GGs The ROC-derived AUC was used to determine whether the inclusion of PSMA quantified parameters improved the ability of multivariable models to predict ISUP GG ≥ 4. A total of 605 patients were included. Overall, 2%, 37%, 37%, 10% and 13% patients had pathologic ISUP GG1, 2, 3, 4, and 5, respectively. At multivariable analyses, all three parameters SUVmax, PSMAvolume and PSMAtotal were associated with GG ≥ 4 at surgical pathology after accounting for PSA and clinical T stage based on DRE, hospital and radioligand (all p < 0.05). Addition of all three parameters significantly improved the discrimination of clinical models in predicting GG ≥ 4 from 68% (95%CI 63 - 74) to 74% (95%CI 69 - 79) for SUVmax, 72% (95%CI 67 - 76) for PSMAvolume, 74% (70 - 79) for PSMAtotal and 75% (95%CI 71 - 80) when all parameters were included (all p < 0.05). Decision-tree analysis resulted in thresholds that discriminate between GG (SUVmax 0-6.5, 6.5-15, 15-28, > 28, PSMAvol 0-2, 2-9, 9-20 and > 20 and PSMAtotal 0-12, 12-98 and > 98). PSMAvolume was significantly associated with GG upgrading (OR 1.03 95%CI 1.01 - 1.05). In patients with biopsy GG1-3, PSMAvolume ≥ 2 was significantly associated with higher odds for upgrading to ISUP GG ≥ 4, compared to PSMAvolume < 2 (OR 6.36, 95%CI 1.47 - 27.6). Quantitative PSMA PET parameters are associated with surgical ISUP GG and upgrading. We propose clinically relevant thresholds of these parameters which can improve in PCa risk stratification in daily clinical practice.

Predicting Isocitrate Dehydrogenase Status in Non-Contrast-Enhanced Adult-Type Astrocytic Tumors Using Diffusion Tensor Imaging and 11C-Methionine, 11C-Choline, and 18F-Fluorodeoxyglucose PET.

We aimed to differentiate the isocitrate dehydrogenase (IDH) status among non-enhanced astrocytic tumors using preoperative MRI and PET. We analyzed 82 patients with non-contrast-enhanced, diffuse, supratentorial astrocytic tumors (IDH mutant [IDH-mut], 55 patients; IDH-wildtype [IDH-wt], 27 patients) who underwent MRI and PET between May 2012 and December 2022. We calculated the fractional anisotropy (FA) and mean diffusivity (MD) values using diffusion tensor imaging. We evaluated the tumor/normal brain uptake (T/N) ratios using 11C-methionine, 11C-choline, and 18F-fluorodeoxyglucose PET; extracted the parameters with significant differences in distinguishing the IDH status; and verified their diagnostic accuracy. Patients with astrocytomas were significantly younger than those with glioblastomas. The following MRI findings were significant predictors of IDH-wt instead of IDH-mut: thalamus invasion, contralateral cerebral hemisphere invasion, location adjacent to the ventricular walls, higher FA value, and lower MD value. The T/N ratio for all tracers was significantly higher for IDH-wt than for IDH-mut. In a composite diagnosis based on nine parameters, including age, 84.4% of cases with 0-4 points were of IDH-mut; conversely, 100% of cases with 6-9 points were of IDH-wt. Composite diagnosis using all parameters, including MRI and PET findings with significant differences, may help guide treatment decisions for early-stage gliomas.

Machine learning techniques based on 18F-FDG PET radiomics features of temporal regions for the classification of temporal lobe epilepsy patients from healthy controls.

This study aimed to investigate the clinical application of 18F-FDG PET radiomics features for temporal lobe epilepsy and to create PET radiomics-based machine learning models for differentiating temporal lobe epilepsy (TLE) patients from healthy controls. A total of 347 subjects who underwent 18F-FDG PET scans from March 2014 to January 2020 (234 TLE patients: 25.50 ± 8.89 years, 141 male patients and 93 female patients; and 113 controls: 27.59 ± 6.94 years, 48 male individuals and 65 female individuals) were allocated to the training (n = 248) and test (n = 99) sets. All 3D PET images were registered to the Montreal Neurological Institute template. PyRadiomics was used to extract radiomics features from the temporal regions segmented according to the Automated Anatomical Labeling (AAL) atlas. The least absolute shrinkage and selection operator (LASSO) and Boruta algorithms were applied to select the radiomics features significantly associated with TLE. Eleven machine-learning algorithms were used to establish models and to select the best model in the training set. The final radiomics features (n = 7) used for model training were selected through the combinations of the LASSO and the Boruta algorithms with cross-validation. All data were randomly divided into a training set (n = 248) and a testing set (n = 99). Among 11 machine-learning algorithms, the logistic regression (AUC 0.984, F1-Score 0.959) model performed the best in the training set. Then, we deployed the corresponding online website version (https://wane199.shinyapps.io/TLE_Classification/), showing the details of the LR model for convenience. The AUCs of the tuned logistic regression model in the training and test sets were 0.981 and 0.957, respectively. Furthermore, the calibration curves demonstrated satisfactory alignment (visually assessed) for identifying the TLE patients. The radiomics model from temporal regions can be a potential method for distinguishing TLE. Machine learning-based diagnosis of TLE from preoperative FDG PET images could serve as a useful preoperative diagnostic tool.

NIMG-23. COMBINATION OF ADC MRI AND FET PET FOR THE ASSESSMENT OF QUANTITATIVE TUMOR PRESENCE IN DIFFUSE GLIOMA

Abstract BACKGROUND Local treatment of diffuse glioma is currently guided by standard MRI sequences. Yet, the combination of apparent diffusion coefficient (ADC) and O-(2-[18F]-fluoroethyl)-L-tyrosine positron emission tomography (FET PET) (ADC/FET) detects qualitatively assessed histopathological tumor presence more accurately than standard MRI imaging. It is unknown whether this is similar for quantitatively assessment of tumor presence. This study compares the diagnostic accuracy of standard imaging and ADC/FET for detecting quantitatively assessment of tumor presence in diffuse glioma. METHODS Fifteen patients with newly diagnosed diffuse glioma were retrospectively included. Pre-operative MRI and FET PET imaging were available. Multiregional image-guided stereotactic biopsies were acquired before craniotomy. Quantitative imaging data from regions-of-interests (ROIs) centered at the biopsy locations was obtained. For each biopsy sample, semi-automatic cellularity and proliferation index, as well as DNA methylation-based tumor purity, was determined. Linear mixed models were used to evaluate which modalities were significant independent predictors for each tumor presence marker, and fitness was assessed using Bayesian Information Criterium. RESULTS 125 biopsies were analyzed (75 from eight high grade and 50 from seven low grade gliomas). Cellularity was associated with T1 weighted MRI (p = 0.033), ADC (p = 0.016) and ADC/FET (p &amp;lt; .001), with ADC/FET as best fit. ADC/FET was the only modality associated with proliferation index (p = 0.003) and with tumor purity (p &amp;lt; .001). CONCLUSION Combined ADC and FET PET is stronger associated with cellularity, proliferation index and tumor purity than standard MRI imaging. These findings may pave the way towards ADC/FET-guided local treatment of diffuse gliomas.

Enhancing PSMA PET/CT imaging of prostate cancer: investigating the impact of multiple time point evaluation, diuretic administration, cribriform pattern, and intraductal carcinoma.

Our objective was to correlate staging PSMA PET imaging parameters to final histopathology. Second objective was to assess the performance of standard versus delayed PSMA PET to detect primary prostate tumor. Thirty-one patients (mean age, 61.4 ± 8.2) who underwent radical prostatectomy and preoperative staging PSMA PET scans were included in the study. After defining dominant lesion in pathology, correlations with PET images were performed. Additionally, two physicians blind to clinical and pathological information retrospectively reviewed staging Ga-68 PSMA PET scans with standard and delayed imaging. Dominant lesion SUV's increased with time 8.2(± 4.5), 10(± 7.1), and 10.2(± 7.8) at 1, 2, and 3h (P = .03 T1-T3). WHO Grade group 3 had highest SUV (group 3 11.9 ± 5.6 vs. group 2 7.9 ± 1.5, p = .02). Addition of cribriform pattern on intraductal component was associated with higher SUV's (11 ± 2.9 vs. 6.5 ± 2.1, p = .01) and higher Gleason four ratios (64 ± 9% vs. 37 ± 17%, p = .01). Intraductal carcinoma was associated with larger tumors (6.3 ± 2.3cm3 vs. 2.6 ± 1.7cm3, p < .001). Physician sensitivities ranged from 61 to 81%. Excluding Gleason 3 + 3 lesions and small lesions (< 1cm3), sensitivities increased to 80-100%. Differences of sensitivity between different time points were not significant. Combined evaluation of all time points did not increase sensitivity. Cribriform pattern correlates with higher Gleason 4 ratios and SUVs in PSMA PET. Intraductal carcinoma is associated with larger tumors but not higher Gleason 4 ratios and SUVs. Multiple late imaging times did not enhance tumor detection and may pose tolerability issues for some patients.

The predictive value, sensitivity, specificity, and accuracy of PET CT in the evaluation of axillary metastases in breast cancer.

This study aims to evaluate the accuracy of preoperative 18F-FDG PET CT in detecting axillary lymph node (ALN) metastases in patients with breast cancer. A retrospective analysis was performed on the medical records of 114 patients who underwent PET CT for breast cancer between January 2017 and January 2020. Clinicopathological features and the relationship between lymph node metastasis were evaluated. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated based on the PET CT findings compared to histopathological results. Among the 67 patients included in this study, 29 were identified as having no axillary involvement, while 38 showed axillary involvement according to preoperative PET CT. Of the 34 patients with histopathologically confirmed metastatic lymph nodes, 28 had PET CT-detected axillary involvement, while 6 did not. Similarly, among the 33 patients without histopathological evidence of lymph node metastasis, 23 had no axillary involvement according to PET CT, while 10 showed axillary involvement. The calculated values were as follows: sensitivity = 82.4% (67-92%), specificity = 69.7% (53-83%), positive predictive value = 73.7% (62-83%), negative predictive value = 79.3% (64%-89%), and accuracy = 76.1% (64-86%). The results suggest that preoperative 18F-FDG PET CT, particularly p SUVmax, can serve as an independent prognostic factor for ALN metastasis in breast cancer patients. Therefore, it may be beneficial for preoperative risk stratification and personalized treatment planning.

Prostate-specific membrane antigen radioguided surgery with negative histopathology: an in-depth analysis

PurposeTo identify reasons for negative histopathology of specimens from prostate-specific membrane antigen (PSMA) radioguided surgery (PSMA-RGS) in recurrent prostate cancer (PCa) after prostatectomy.MethodsOf 302 patients who underwent PSMA-RGS, 17 (5.6%) demonstrated a negative histopathology. Preoperative data, PSMA PET, PSMA SPECT, and follow-up information were analyzed retrospectively to differentiate true/false positive (TP/FP) from true/false negative (TN/FN) lesions.ResultsThe median prostate-specific antigen at PET was 0.4 ng/ml (interquartile range [IQR] 0.3–1.2). Twenty-five index lesions (median short axis 7 mm, IQR 5–8; median long-axis 12 mm, IQR 8–17) had a median SUVmax of 4 (IQR 2.6–6; median PSMA expression score 1, IQR 1–1). Six lesions were TP, twelve were FP, one was TN, and six remained unclear. All TP lesions were in the prostatic fossa or adjacent to the internal iliac arteries. Three suspected local recurrences were FP. All FP lymph nodes were located at the distal external iliac arteries or outside the pelvis. A low PSMA-expressing TN node was identified next to a common iliac artery. Unclear lesions were located next to the external iliac arteries or outside the pelvis.ConclusionIn most cases with a negative histopathology from PSMA-RGS, lesions were FP on PSMA PET. Unspecific uptake should be considered in low PSMA-expressing lymph nodes at the distal external iliac arteries or outside the pelvis, especially if no PSMA-positive lymph nodes closer to the prostatic fossa are evident. Rarely, true positive metastases were missed by surgery or histopathology.

A Rare Axillary Lymph Node Metastasis on 18F-FDG PET/CT for Staging in a Patient with Common Bile Duct Cancer.

Distant metastasis of cholangiocarcinoma is most commonly diagnosed in the liver; however, it can also be found in the lungs, distant lymph nodes, bones, and brain. Distant lymph node metastasis outside the abdominal region without concurrent abdominal metastasis is exceedingly rare in extrahepatic cholangiocarcinoma. Herein, we present interesting 18F-FDG PET/CT images of a 49-year-old male patient with common bile duct cancer. In this case, the patient, who was scheduled for surgery, unexpectedly showed axillary lymph node metastasis on a preoperative 18F-FDG PET scan, which was subsequently confirmed via histological examination. Although such cases are exceptionally rare, this accurate diagnosis prompted a modification of the treatment plan, leading to a positive therapeutic response.

Which Patients with Prostate Cancer and Lymph Node Uptake at Preoperative Prostate-specific Membrane Antigen Positron Emission Tomography/Computerized Tomography Scan Are at a Higher Risk of Prostate-specific Antigen Persistence After Radical Prostatectomy? Identifying Indicators of Systemic Disease by Integrating Clinical, Magnetic Resonance Imaging, and Functional Imaging Parameters

BackgroundThe role of local therapies including radical prostatectomy (RP) in prostate cancer (PCa) patients with clinical lymphadenopathies on prostate-specific membrane antigen (PSMA) positron emission tomography/computerized tomography (PET/CT) has scarcely been explored. Limited data are available to identify men who would benefit from RP; on the contrary, those more likely to benefit already have systemic disease. ObjectiveWe aimed to assess the predictors of prostate-specific antigen (PSA) persistence in surgically managed PCa patients with lymphadenopathies on a PSMA PET/CT scan by integrating clinical, magnetic resonance imaging (MRI), and PSMA PET/CT parameters. Design, setting, and participantsWe identified 519 patients treated with RP and extended lymph node dissection, and who received preoperative PSMA PET between 2017 and 2022 in nine referral centers. Among them, we selected 88 patients with nodal uptake at preoperative PSMA PET (miTxN1M0). Outcome measurements and statistical analysisThe outcome was PSA persistence, defined as a PSA value of ≥0.1 ng/ml at the first measurement after surgery. Multivariable logistic regression models tested the predictors of PSA persistence. Covariates consisted of biopsy International Society of Urological Pathology (ISUP) grade group, clinical stage at MRI, and number of positive spots at a PET/CT scan. A regression tree analysis stratified patients into risk groups based on preoperative characteristics. Results and limitationsOverall, lymph node invasion (LNI) was detected in 63 patients (72%) and 32 (36%) experienced PSA persistence after RP. At multivariable analyses, having more than two lymph nodal positive findings at PSMA PET, seminal vesicle invasion (SVI) at MRI, and ISUP grade group >3 at biopsy were independent predictors of PSA persistence (all p < 0.05). At the regression tree analysis, patients were stratified in four risk groups according to biopsy ISUP grade, number of positive findings at PET/CT, and clinical stage at MRI. The model depicted good discrimination at internal validation (area under the curve 78%). ConclusionsOne out of three miN1M0 patients showed PSA persistence after surgery. Patients with ISUP grade 2–3, as well as patients with organ-confined disease at MRI and a single or two positive nodal findings at PET are those in whom RP may achieve the best oncological outcomes in the context of a multimodal approach. Conversely, patients with a high ISUP grade and extracapsular extension or SVI or more than two spots at PSMA PET should be considered as potentially affected by systemic disease upfront. Patient summaryOur novel and straightforward risk classification integrates currently available preoperative risk tools and should, therefore, assist physician in preoperative counseling of men candidates for radical treatment for prostate cancer with positive lymph node uptake at prostate-specific membrane antigen positron emission tomography.

JS09.7.A COMBINATION OF APPARENT DIFFUSION COEFFICIENT AND FET PET COMPARED WITH STANDARD IMAGING FOR QUANTITATIVE TUMOR PRESENCE IN DIFFUSE GLIOMAS

Abstract BACKGROUND Diffuse glioma local treatment is currently guided by standard MRI sequences. Yet, the combination of apparent diffusion coefficient (ADC) and O-(2-[18F]-fluoroethyl)-L-tyrosine positron emission tomography (FET PET) (ADC/FET) detects histopathological qualitative assessed tumor presence more accurately than standard imaging. It is unknown whether this is similar for quantitative assessed tumor presence. This study compares the diagnostic accuracy of standard imaging and ADC/FET for the detection of quantitative assessed tumor presence in diffuse glioma. MATERIAL AND METHODS Fifteen patients with newly diagnosed diffuse glioma were retrospectively included. Pre-operative standard imaging, ADC and FET PET were available. Multiregional image-guided stereotactic biopsies were acquired before craniotomy. Quantitative imaging data from regions-of-interests (ROIs) centered at the biopsy locations was obtained. For each biopsy, sample semi-automatic cellularity and proliferation index, as well as DNA methylation-based tumor purity was determined. Linear mixed models were used to evaluate which modalities were significant independent predictors for each tumor presence marker and fitness was assessed using Bayesian Information Criterium. RESULTS 125 biopsies were analyzed (75 from eight high grade and 50 from seven low grade gliomas). Cellularity was predicted by T1 weighted MRI (p = 0.033), ADC (p = 0.016) and ADC/FET (p &amp;lt;.001), with ADC/FET as best fit. Both proliferation index (p = 0.003) and tumor purity (p &amp;lt;.001) were only predicted by ADC/FET. CONCLUSION Combining ADC and FET PET predicts cellularity, proliferation index and tumor purity better than standard imaging. Further investigation into ADC/FET-guided local treatment of diffuse glioma is therefore needed.

PET Imaging and Protein Expression of Prostate-Specific Membrane Antigen in Glioblastoma: A Multicenter Inventory Study.

Upregulation of prostate-specific membrane antigen (PSMA) in neovasculature has been described in glioblastoma multiforme (GBM), whereas vasculature in nonaffected brain shows hardly any expression of PSMA. It is unclear whether PSMA-targeting tracer uptake on PET is based on PSMA-specific binding to neovasculature or aspecific uptake in tumor. Here, we quantified uptake of various PSMA-targeting tracers in GBM and correlated this with PSMA expression in tumor biopsy samples from the same patients. Methods: Fourteen patients diagnosed with de novo (n = 8) or recurrent (n = 6) GBM underwent a preoperative PET scan after injection of 1.5 MBq/kg [68Ga]Ga-PSMA-11 (n = 7), 200 MBq of [18F]DCFpyl (n = 3), or 200 MBq of [18F]PSMA-1007 (n = 4). Uptake in tumor and tumor-to-background ratios, with contralateral nonaffected brain as background, were determined. In a subset of patients, PSMA expression levels from different regions in the tumor tissue samples (n = 40), determined using immunohistochemistry (n = 35) or RNA sequencing (n = 13), were correlated with tracer uptake on PET. Results: Moderate to high (SUVmax, 1.3-20.0) heterogeneous uptake was found in all tumors irrespective of the tracer type used. Uptake in nonaffected brain was low, resulting in high tumor-to-background ratios (6.1-359.0) calculated by dividing SUVmax of tumor by SUVmax of background. Immunohistochemistry showed variable PSMA expression on endothelial cells of tumor microvasculature, as well as on dispersed individual cells (of unknown origin), and granular staining of the neuropil. No correlation was found between invivo uptake and PSMA expression levels (for immunohistochemistry, r = -0.173, P = 0.320; for RNA, r = -0.033, P = 0.915). Conclusion: Our results indicate the potential use of various PSMA-targeting tracers in GBM. However, we found no correlation between PSMA expression levels on immunohistochemistry and uptake intensity on PET. Whether this may be explained by methodologic reasons, such as the inability to measure functionally active PSMA with immunohistochemistry, tracer pharmacokinetics, or the contribution of a disturbed blood-brain barrier to tracer retention, should still be investigated.

FDG-PET/CT response and prediction of pathological response to neoadjuvant nivolumab and ipilimumab for clinical stage III melanoma.

9585 Background: Neoadjuvant immunotherapy with nivolumab 3mg/kg and ipilimumab 1 mg/kg (N3+I1) for two cycles for clinical stage III melanoma have shown rates of major pathological response (MPR) of approximately 60%.The prognosis of this group seems to be excellent so far. On the other hand, patients classified as pathological non-responders have a worse outcome and early identification of this group may allow us to tailor the treatment before surgery. Methods: We conducted a multicenter retrospective analysis of patients with clinical stage III melanoma treated with neoadjuvant N3+I1 for two cycles who did baseline and pre-operative 18F-FDG-PET/CT. The total number of FGD avid lesions and the percentual difference between the maximum SUV per lesion was calculated. The pathological results were correlated to FGD-PET/CT findings. Results: Between January 2019 and January 2023, 28 patients with clinical stage III melanoma treated with N3+I1 who had baseline and preoperative 18F-FDG PET were identified. Gender: 20 (71%) males, median age (range):55 (34-78), BRAFV600E/K mut: 15(53%), positive nodes on baseline PET/CT:1 = 26 (92%), 2 = 1(4%), and 3 = 1(4%). All known lesions identified by CT scan were also captured by FGD-PET/CT. Site of node(s): axilla = 12 (43%), cervical = 10 (36%), and inguinal = 6(21%). All but one patient received 2 cycles of N3+IP1(1 patient had grade 3 toxicity and received only one cycle). Pathological response: MPR = 19(68%), non-MPR: 8 (28%), and 1(4%) did not undergo surgery due to widespread progression. An increase in maximum SUV and/or appearance of new lesion(s), n = 8(28%), was correlated to non-MPR or metastatic disease in all cases, including a patient who developed sarcoidosis-like reaction with increase of SUV in the index lesion (+68%) and appearance of inflammatory mediastinal lymph-nodes. The median increase was (range): +73% (+11% to 483%). Reduction or stable maximum SUV with no appearance of new lesion, n = 20 (72%), was associated with MPR in 19 patients (95%). One patient,who had G3 colitis (with the need of infliximab), had 32% of reduction in maximum SUV but 100% of viable tumor cells on pathological report. The median decrease (range) was -76% (-1.2% to -100%). Conclusions: FGD-PET/CT may help to predict pathological response in patients with clinical stage III melanoma who undergo to neoadjuvant nivolumab and ipilimumab.

Negative predictive value of PSMA PET scan for lymph node staging in patients undergoing robotic radical prostatectomy and pelvic lymph node dissection

To assess the negative predictive value of PSMA PET scan for lymph node staging in patients undergoing robotic radical prostatectomy and pelvic lymph node dissection. A retrospective analysis of patients who underwent robotic-assisted radical prostatectomy with pelvic lymph node dissection and had a preoperative negative PSMA PET scan for metastasis was performed. The documented pre-operative variables studied included age, BMI, PSA at diagnosis, Gleason score, and biopsy ISUP grades. Patients were categorised as low, intermediate and high risk according to the D Amico classification. The post-op variables included were number of lymph nodes harvested, number of positive nodes, positivity rate, size of the node metastasis, T staging and ISUP grading. The overall negative predictive value of PSMA PET scan was 71.6%. Further sub-classification according to risk stratification demonstrated a NPV of 58.02%, 92.7% and 90% for high, intermediate and low risk, respectively. Pelvic lymph node dissection cannot be excluded based on a negative preop PSMA PET/CT scan.

MP61-12 WHICH MEN WITH CN1 PROSTATE CANCER AT PSMA PET/CT REPRESENT THE IDEAL CANDIDATE TO RADICAL PROSTATECTOMY? DEVELOPMENT OF A NOVEL RISK STRATIFICATION TOOL FOR INDIVIDUALIZED APPROACHES BASED ON A LARGE, MULTI-INSTITUTIONAL SERIES

MP61-12 WHICH MEN WITH CN1 PROSTATE CANCER AT PSMA PET/CT REPRESENT THE IDEAL CANDIDATE TO RADICAL PROSTATECTOMY? DEVELOPMENT OF A NOVEL RISK STRATIFICATION TOOL FOR INDIVIDUALIZED APPROACHES BASED ON A LARGE, MULTI-INSTITUTIONAL SERIES

Metabolic delineation of IDH1 wild-type glioblastoma surgical anatomy: how to plan the tumor extent of resection.

Magnetic resonance imaging (MRI) is the current standard for preoperative planning of glioblastoma (GBM) surgery. However, recent data on the use of 11C-methionine positron emission tomography (11[C]-MET PET) suggest its role in providing additional information beyond MRI. The purpose of this study is to establish if there is a correlation between anatomical and metabolic data. We retrieved all GBM cases treated from 2014 to January 2021. Preoperative MRI (Enhancing Nodule -EN-, FLAIR and Total Tumor Volume -TTV-), PET volumes and histological samples obtained from the different tumor regions were evaluated to analyze potential correlations between anatomical, metabolic and pathological data. 150 patients underwent surgery for GBM and 49 of these were also studied preoperatively with 11[C]-MET PET; PET volume was evaluated in 47 patients. In 33 patients (70.21%) preoperative 11[C]-MET PET volume > preoperative EN volume and in 11 (23.4%) preoperative 11[C]-MET PET volume > preoperative TTV. We found a significant correlation between preoperative TTVs and PET volumes (p = 0.016) as well as between preoperative EN volumes and PET volumes (p = < 0.001). Histologically, 109 samples were evaluated. ENs samples exhibited the conventional GBM morphology while samples from the FLAIR regions showed white matter tissue, with focal to diffuse tumor cells infiltration and areas of reactive astrogliosis. We submit that 11[C]-MET PET volume generally overcome EN. The presence of neoplastic cells confirm these metabolic data. It should be considered in the surgical planning to achieve a Supra Total Resection (SupTR).

PD22-05 IS PRE OPERATIVE PSMA (PROSTATE SPECIFIC MEMBRANE ANTIGEN) PET/CT A RELIABLE PREDICTOR OF PELVIC LYMPH NODE METASTASIS IN INTERMEDIATE AND HIGH RISK LOCALISED PROSTATE CANCER:A MULTI CENTRE RETROSPECTIVE ANALYSIS

You have accessJournal of UrologyCME1 Apr 2023PD22-05 IS PRE OPERATIVE PSMA (PROSTATE SPECIFIC MEMBRANE ANTIGEN) PET/CT A RELIABLE PREDICTOR OF PELVIC LYMPH NODE METASTASIS IN INTERMEDIATE AND HIGH RISK LOCALISED PROSTATE CANCER:A MULTI CENTRE RETROSPECTIVE ANALYSIS Kishore Ta, Dinesh Cherian, Deepak Kaddu, Bikramjit Sodhi, Ravi Chandran, and Ginil Kumar Pooleri Kishore TaKishore Ta More articles by this author , Dinesh CherianDinesh Cherian More articles by this author , Deepak KadduDeepak Kaddu More articles by this author , Bikramjit SodhiBikramjit Sodhi More articles by this author , Ravi ChandranRavi Chandran More articles by this author , and Ginil Kumar PooleriGinil Kumar Pooleri More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003295.05AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Functional imaging techniques have been incorporated into conventional anatomical imaging to help improve identification of metastasis in normal sized nodes The primary objective of this study was to retrospectively analyse the percentage of patients “negative for metastasis” on 68Ga PSMA PETCT that translated to absent pelvic node metastasis on histopathology (Negative predictive value-NPV). The secondary objective was to analyse if pathological T stage and biopsy ISUP grades influenced the NPV of the PSMA PET CT. METHODS: A total of 217 biopsy-proven, treatment-naive, intermediate and high-risk (D’Amico classification) localised prostate cancer patients from two institutions were included in the study. All the patients had undergone a pre operative PSMA PET/ CT assessment of their pelvic lymph nodes and the patients “negative for metastasis” underwent Robotic assisted radical prostatectomy with extended pelvic lymph node dissection-ePLND. RESULTS: 49/217 patients had positive nodes despite PSMA PET/CT showing no evidence of lymph node metastasis,of which 27(55.10%) of them were obese. Thus the negative predictive value(NPV) was 77.42%. The NPV of PSMA PET CT in patients with intermediate risk prostate cancer was 86.9% compared to 71.43% in patients with high risk prostate cancer. As the ISUP biopsy grade increased the NPV decreased from 94.12% in ISUP 1 to 44.83%(p<0.0001) in ISUP 5.On retrospective analysis, all intermediate risk patients with a <pT3 stage had a 100% NPV on the PSMA PET/CT while high risk patients with a <pT3 had a NPV of 91.6%.The secondary objective was to analyse if T stage influenced the NPV .In comparison to organ confined disease(pT2) the NPV of those with disease extending beyond the prostate(pT3) was significantly lower, (80.36% vs100%) in intermediate risk and (66.97% vs 91.6%)in high risk patients. CONCLUSIONS: PSMA PET CT cannot replace e PLND with respect to accurate preoperative lymph nodal staging in intermediate and high risk prostate cancer since the NPV is below 95% (86.9%,71.43% respectively. PSMA PET CT is also not accurate with the T staging because pre operative T2 was upstaged to pT3 in 66.6 % of intermediate risk and 81.9% of high risk patients.Thus preoperative PSMA PET CT is not reliable for accurate T and N staging and e PLND should be the standard of care for precise staging in intermediate and high risk localized prostate cancer. Source of Funding: Self funded study © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e666 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Kishore Ta More articles by this author Dinesh Cherian More articles by this author Deepak Kaddu More articles by this author Bikramjit Sodhi More articles by this author Ravi Chandran More articles by this author Ginil Kumar Pooleri More articles by this author Expand All Advertisement PDF downloadLoading ...

Preoperative PET-SUVmax and volume based PET parameters of the primary tumor fail to predict nodal upstaging in early-stage lung cancer

ObjectivesAccurate nodal staging is of utmost importance in patients with lung cancer. FDG-PET/CT imaging is now part of the routine staging. Despite thorough preoperative staging nodal upstaging still occurs in early-stage lung cancer. However, the predictive value of preoperative PET metrics of the primary tumor on nodal upstaging remains to be unexplored. Our aim was to assess the association of these preoperative PET-parameters with nodal upstaging in histologically confirmed lung adenocarcinoma and squamous cell carcinoma. MethodsFrom January 2016 to November 2018, 500 patients with pT1-T2/cN0 lung cancer received an anatomical resection with curative intent. 171 patients with adenocarcinoma and squamous cell carcinoma and available PET-CTs were retrospectively included. We analyzed the the association of nodal upstaging with preoperative PET-SUVmax and metabolic PET metrics including total lesion glycolysis (TLG) and metabolic tumor volume (MTV) with different defined thresholds. ResultsHigh values of preoperative PET-SUVmax of the primary tumor were associated with squamous cell carcinoma (p < 0.0001) and with larger tumors (p < 0.0001). Increased preoperative C-reactive protein levels (<1mg/dL) correlated significantly with high preoperative PET-SUVmax values (p < 0.0001). No significant relationship between PET-SUVmax and lactate dehydrogenase activity (p = 0.6818), white blood cell count (p = 0.7681), gender (p = 0.1115) or age (p = 0.9284) was observed. Nodal upstaging rate was 14.0 % with 8.8 % N1 and 5.3 % N2 upstaging. Tumor size (p = 0.0468) and number of removed lymph nodes (p = 0.0461) were significant predictors of nodal upstaging but no significant association was found with histology or PET parameters. Of note, increased MTV – regardless of the threshold – tended to associate with nodal upstaging. ConclusionEarly-stage lung cancer patients with squamous histology and T2 tumors presented increased preoperative PET-SUVmax values. Nevertheless, beyond tumor size and number of removed lymph nodes neither SUVmax nor metabolic PET parameters MTV and TLG were significant predictors of nodal upstaging.

Distinguishing Progression from Pseudoprogression in Glioblastoma Using 18F-Fluciclovine PET.

Accurate differentiation between tumor progression (TP) and pseudoprogression remains a critical unmet need in neurooncology. 18F-fluciclovine is a widely available synthetic amino acid PET radiotracer. In this study, we aimed to assess the value of 18F-fluciclovine PET for differentiating pseudoprogression from TP in a prospective cohort of patients with suspected radiographic recurrence of glioblastoma. Methods: We enrolled 30 glioblastoma patients with radiographic progression after first-line chemoradiotherapy for whom surgical resection was planned. The patients underwent preoperative 18F-fluciclovine PET and MRI. The relative percentages of viable tumor and therapy-related changes observed in histopathology were quantified and categorized as TP (≥50% viable tumor), mixed TP (<50% and >10% viable tumor), or pseudoprogression (≤10% viable tumor). Results: Eighteen patients had TP, 4 had mixed TP, and 8 had pseudoprogression. Patients with TP/mixed TP had a significantly higher 40- to 50-min SUVmax (6.64 + 1.88 vs. 4.11 ± 1.52, P = 0.009) than patients with pseudoprogression. A 40- to 50-min SUVmax cutoff of 4.66 provided 90% sensitivity and 83% specificity for differentiation of TP/mixed TP from pseudoprogression (area under the curve [AUC], 0.86). A maximum relative cerebral blood volume cutoff of 3.672 provided 90% sensitivity and 71% specificity for differentiation of TP/mixed TP from pseudoprogression (AUC, 0.779). Combining a 40- to 50-min SUVmax cutoff of 4.66 and a maximum relative cerebral blood volume of 3.67 on MRI provided 100% sensitivity and 80% specificity for differentiating TP/mixed TP from pseudoprogression (AUC, 0.95). Conclusion: 18F-fluciclovine PET uptake can accurately differentiate pseudoprogression from TP in glioblastoma, with even greater accuracy when combined with multiparametric MRI. Given the wide availability of 18F-fluciclovine, larger, multicenter studies are warranted to determine whether amino acid PET with 18F-fluciclovine should be used in the routine posttreatment assessment of glioblastoma.

The Association of Preoperative PET-CT and Survival in Patients with Resectable Cervical Cancer.

No randomized study with a long-term follow-up has investigated the effect of pretreatment 18-fluorodeoxyglucose positron emission tomography-computed tomography (18FDG-PET-CT) on the survival of patients with stage IB-IIA cervical cancer receiving curative surgery. Therefore, in this propensity score-matched, population-based cohort study, we investigated the effect of preoperative 18FDG-PET-CT on the survival outcomes of patients with potentially resectable cervical cancer. We included 2550 patients with stage IB-IIA cervical cancer receiving curative surgery with complete data on clinical stages. The patients were categorized into two 1:4 propensity, score-matched groups depending on whether they underwent pretreatment 18FDG-PET-CT, and their outcomes were compared. We included 2030 and 520 patients with cervical cancer in the non-pretreatment and pretreatment PET-CT groups, respectively. Multivariable analyses revealed that the most prominent correlation between preoperative PET-CT and all-cause death was observed in the patients with stage IB-IIA cervical cancer receiving surgery (aHR [95% CI]: 1.16 [0.83-1.63]; p = 0.3752). Preoperative 18FDG-PET-CT was not associated with longer survival in the patients with clinical stage IB-IIA cervical cancer receiving curative surgery.