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1.
AJR Am J Roentgenol ; 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34985313

RESUMO

Neuroendocrine neoplasms (NENs) encompass a broad spectrum of tumors throughout the body and range in biologic behavior from indolent to aggressive. Consequently, a wide spectrum of treatment options are available for NENs, including observation, somatostatin analogs, targeted therapy, chemotherapy, surgical resection, liver-directed therapy (embolization and ablation), and peptide receptor radionuclide therapy. Given the wide variety of tumor behaviors and treatments, precise criteria for treatment response in NENs are lacking. While conventional anatomic imaging with CT and MRI remains important for NEN response assessment, the use of somatostatin receptor (SSR) PET is increasing and often provides synergistic and complementary information. Additionally, in certain clinical scenarios, a particular imaging strategy may prove superior or inferior to others for the detection of metastatic disease and evaluation of therapy response. A strong need exists to further define appropriate and standardized assessment criteria for tumor response and progression in NEN. This article aims to present the strengths and weaknesses for evaluating NEN therapy response of individual imaging modalities, including conventional anatomic imaging, SSR PET, FDG PET, dual tracer PET, and PET/MRI. Ongoing challenges and unmet needs in the use of imaging for NEN response evaluation are explored.

2.
Cancer Imaging ; 22(1): 3, 2022 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-34983677

RESUMO

18F-FDG PET/CT plays an increasingly pivotal role in the staging and post-treatment monitoring of high-risk melanoma patients, augmented by the introduction of therapies, including tyrosine kinase inhibitors (TKI) and immune checkpoint inhibitors (ICIs), that have novel modes of action that challenge conventional response assessment. Simultaneously, technological advances have been regularly released, including advanced reconstruction algorithms, digital PET and motion correction, which have allowed the PET community to detect ever-smaller cancer lesions, improving diagnostic performance in the context of indications previously viewed as limitations, such as detection of in-transit disease and confirmation of the nature of small pulmonary metastases apparent on CT.This review will provide advice regarding melanoma-related PET protocols and will focus on variants encountered during the imaging of melanoma patients. Emphasis will be made on pitfalls related to non-malignant diseases and treatment-related findings that may confound accurate interpretation unless recognized. The latter include signs of immune activation and immune-related adverse events (irAEs). Technology-related pitfalls are also discussed, since while new PET technologies improve detection of small lesions, these may also induce false-positive cases and require a learning curve to be observed. In these times of the COVID 19 pandemic, cases illustrating lessons learned from COVID 19 or vaccination-related pitfalls will also be described.


Assuntos
COVID-19 , Melanoma , Neoplasias Cutâneas , Fluordesoxiglucose F18 , Humanos , Melanoma/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Tomografia por Emissão de Pósitrons , Compostos Radiofarmacêuticos , SARS-CoV-2 , Neoplasias Cutâneas/diagnóstico por imagem
3.
J Nucl Med ; 62(Suppl 3): 12S-22S, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34857617

RESUMO

Radiopharmaceutical therapy (RPT) is defined as the delivery of radioactive atoms to tumor-associated targets. In RPT, imaging is built into the mode of treatment since the radionuclides used in RPT often emit photons or can be imaged using a surrogate. Such imaging may be used to estimate tumor-absorbed dose. We examine and try to elucidate those factors that impact the absorbed dose-versus-response relationship for RPT agents. These include the role of inflammation- or immune-mediated effects, the significance of theranostic imaging, radiobiology, differences in dosimetry methods, pharmacokinetic differences across patients, and the impact of tumor hypoxia on response to RPT.

5.
J Nucl Med ; 62(Suppl 3): 60S-72S, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34857623

RESUMO

The use of radiopharmaceutical therapies (RPTs) in the treatment of cancers is growing rapidly, with more agents becoming available for clinical use in last few years and many new RPTs being in development. Dosimetry assessment is critical for personalized RPT, insofar as administered activity should be assessed and optimized in order to maximize tumor-absorbed dose while keeping normal organs within defined safe dosages. However, many current clinical RPTs do not require patient-specific dosimetry based on current Food and Drug Administration-labeled approvals, and overall, dosimetry for RPT in clinical practice and trials is highly varied and underutilized. Several factors impede rigorous use of dosimetry, as compared with the more convenient and less resource-intensive practice of empiric dosing. We review various approaches to applying dosimetry for the assessment of activity in RPT and key clinical trials, the extent of dosimetry use, the relative pros and cons of dosimetry-based versus fixed activity, and practical limiting factors pertaining to current clinical practice.

6.
Theranostics ; 11(20): 9721-9737, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34815780

RESUMO

Rationale: Alpha particle emitting radiopharmaceuticals are generating considerable interest for the treatment of disseminated metastatic disease. Molecular imaging of the distribution of these agents is critical to safely and effectively maximize the clinical potential of this emerging drug class. The present studies aim to investigate the feasibility and limitations of quantitative SPECT for 223Ra, 225Ac and 227Th. Methods: Three state-of-the-art SPECT/CT systems were investigated: the GE Discovery NM/CT 670, the GE Optima NM/CT 640, and the Siemens Symbia T6. A series of phantoms, including the NEMA IEC Body phantom, were used to compare and calibrate each camera. Additionally, anthropomorphic physical tumor and vertebrae phantoms were developed and imaged to evaluate the quantitative imaging protocol. Results: This work describes and validates a methodology to calibrate each clinical system. The efficiency of each gamma camera was analyzed and compared. Using the calibration factors obtained with the NEMA phantom, we were able to quantify the activity in 3D-printed tissue phantoms with an error of 2.1%, 3.5% and 11.8% for 223Ra, 225Ac, and 227Th, respectively. Conclusion: The present study validates that quantitative SPECT/CT imaging of 223Ra, 225Ac, and 227Th is achievable but that careful considerations for camera configuration are required. These results will aid in future implementation of SPECT-based patient studies and will help to identify the limiting factors for accurate image-based quantification with alpha particle emitting radionuclides.

7.
Acta Radiol ; : 2841851211054193, 2021 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-34713716

RESUMO

BACKGROUND: Myocardial uptake on 68Ga-DOTATATE PET/CT is often observed and its clinical relevance is poorly understood. PURPOSE: To detect any correlation between myocardial uptake of 68Ga-DOTATATE and presence of cardiac disease or risk factors. MATERIAL AND METHODS: In this institutional review board-approved retrospective study, we reviewed 68Ga-DOTATATE PET/CT scans in our institution between 1 May 2018 and 30 September 2018. A semi-quantitative score (MUS) for myocardial uptake of 68Ga-DOTATATE was developed by measuring mean standardized uptake value (SUV) in five myocardial regions, corrected by blood pool activity, and MUS was validated between two readers. We investigated the relationship between MUS and presence of cardiac disease or risk factors, including Framingham score and coronary calcification. RESULTS: A total of 145 scans were included (79 women; mean age = 56.9 ± 13.7 years). Inter-reader agreement was excellent with intraclass correlation coefficient (r) = 0.964 (95% confidence interval [CI] = 0.903-0.987; P < 0.001). There was a weak but significant positive correlation between MUS and presence of coronary calcifications (Spearman rho = 0.20; P = 0.016). MUS was higher in patients with heart disease or risk factors (n = 83, mean MUS 2.03, 95% CI = 1.85-2.21) compared to those without (n = 23, mean MUS 1.40, 95% CI = 1.17-1.62; P < 0.001), although the cardiac disease group was older with a higher percentage of men (62.0 years, 57.8% men compared to 47.6 years, 13.0% men; P value <0.0001 for both comparisons). CONCLUSION: For patients undergoing 68Ga-DOTATATE PET/CT scan, an elevated MUS might indicate an underlying heart disease.

8.
J Immunother Cancer ; 9(10)2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34625515

RESUMO

BACKGROUND: Melanoma brain metastases (MBMs) are a challenging clinical problem with high morbidity and mortality. Although first-line dabrafenib-trametinib and ipilimumab-nivolumab have similar intracranial response rates (50%-55%), central nervous system (CNS) resistance to BRAF-MEK inhibitors (BRAF-MEKi) usually occurs around 6 months, and durable responses are only seen with combination immunotherapy. We sought to investigate the utility of ipilimumab-nivolumab after MBM progression on BRAF-MEKi and identify mechanisms of resistance. METHODS: Patients who received first-line ipilimumab-nivolumab for MBMs or second/third line ipilimumab-nivolumab for intracranial metastases with BRAFV600 mutations with prior progression on BRAF-MEKi and MRI brain staging from March 1, 2015 to June 30, 2018 were included. Modified intracranial RECIST was used to assess response. Formalin-fixed paraffin-embedded samples of BRAFV600 mutant MBMs that were naïve to systemic treatment (n=18) or excised after progression on BRAF-MEKi (n=14) underwent whole transcriptome sequencing. Comparative analyses of MBMs naïve to systemic treatment versus BRAF-MEKi progression were performed. RESULTS: Twenty-five and 30 patients who received first and second/third line ipilimumab-nivolumab, were included respectively. Median sum of MBM diameters was 13 and 20.5 mm for the first and second/third line ipilimumab-nivolumab groups, respectively. Intracranial response rate was 75.0% (12/16), and median progression-free survival (PFS) was 41.6 months for first-line ipilimumab-nivolumab. Efficacy of second/third line ipilimumab-nivolumab after BRAF-MEKi progression was poor with an intracranial response rate of 4.8% (1/21) and median PFS of 1.3 months. Given the poor activity of ipilimumab-nivolumab after BRAF-MEKi MBM progression, we performed whole transcriptome sequencing to identify mechanisms of drug resistance. We identified a set of 178 differentially expressed genes (DEGs) between naïve and MBMs with progression on BRAF-MEKi treatment (p value <0.05, false discovery rate (FDR) <0.1). No distinct pathways were identified from gene set enrichment analyses using Kyoto Encyclopedia of Genes and Genomes, Gene Ontogeny or Hallmark libraries; however, enrichment of DEG from the Innate Anti-PD1 Resistance Signature (IPRES) was identified (p value=0.007, FDR=0.03). CONCLUSIONS: Second-line ipilimumab-nivolumab for MBMs after BRAF-MEKi progression has poor activity. MBMs that are resistant to BRAF-MEKi that also conferred resistance to second-line ipilimumab-nivolumab showed enrichment of the IPRES gene signature.

9.
J Nucl Med ; 62(10): 1438-1439, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34353872
10.
J Med Imaging Radiat Oncol ; 65(6): 748-754, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34318603

RESUMO

INTRODUCTION: This study aims to investigate whether nodal metabolic tumour volume (nMTV) and nodal total lesion glycolysis (nTLG) on Fluorine-18 fluoro-deoxy-glucose positron emission tomography-computed tomography (18 F-FDG PET/CT) in inoperable node-positive stage II and III non-small cell lung cancer (NSCLC) are independent predictors of overall survival (OS) in patients undergoing curative-intent chemoradiotherapy/radiotherapy (CRT/RT). METHODS: Data from two prospective trials between 2004 and 2016 were analysed retrospectively. Primary, nodal and total metabolic tumour volume and total lesion glycolysis (pMTV, nMTV, tMTV, pTLG, nTLG and tTLG, respectively) were derived from baseline 18 F-FDG PET/CT. Cox regressions were used to model OS by 18 F-FDG PET/CT parameters adjusting for overall stage. RESULTS: 89 patients with stage II (8%) and stage III (92%) were included. The median age at diagnosis was 67 years; 62% were male. The median follow-up was 6.9 years; the median OS was 2.2 years (95% CI 1.7-3.1). The median pMTV, nMTV and tMTV were 14 mL (range 0-360), 8 mL (range 0-250) and 34 mL (range 3-384), respectively. In 3 patients, the primary lesion could not be delineated from the central hilar mass. There was no association between nMTV (adjusted HR 1.04, 95% CI 0.95-1.15, P-value 0.43), pMTV (adjusted HR 1.0, 95% CI 0.96-1.04, P-value 0.92), tMTV (adjusted HR 1.0, 95% CI 0.97-1.04, P-value 0.88), nTLG, pTLG or tTLG and OS. Consistent results were noted when patients with central hilar lesions were excluded from analysis. CONCLUSION: In node-positive stage II and III NSCLC patients who underwent 18 F-FDG PET/CT-guided target delineation curative-intent concurrent CRT/RT, metabolic parameters did not appear to provide independent prognostication.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Carcinoma Pulmonar de Células não Pequenas/diagnóstico por imagem , Carcinoma Pulmonar de Células não Pequenas/terapia , Quimiorradioterapia , Fluordesoxiglucose F18 , Humanos , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/terapia , Masculino , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Prognóstico , Estudos Prospectivos , Estudos Retrospectivos , Carga Tumoral
11.
J Nucl Med ; 2021 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-34049983

RESUMO

To assess the efficacy and safety of 177Lu-DOTATATE in patients with somatostatin receptor (SSR) positive lung neuroendocrine tumor (NET). Methods: This is a retrospective review of the outcome of patients with typical carcinoid (TC) and atypical carcinoid (AC), treated with 177Lu-DOTATATE at two ENETS Centres of Excellence. Morphological imaging (RECIST 1.1) and 68Ga-DOTATATE PET/CT responses were assessed at 3 months after completion of 177Lu-DOTATATE. Concordance between two response assessment methods was evaluated by Kappa statistics. Progression-free survival (PFS) and overall survival (OS) was estimated by Kaplan-Meier analysis and compared by Log-rank test. Treatment-related adverse events (AEs) were graded based on CTCAE version 5. Results: Of 48 patients (median age, 63 years, 13 female), 43 (90%) had AC and 5 (10%) TC. Almost all patients (47, 98%) were treated due to progression. Majority (40, 83%) received somatostatin analogs and 10 patients (20%) had prior everolimus, chemotherapy or both. All patients had high SSR expression (≥ modified Krenning score 3) on pre-treatment 68Ga-DOTATATE PET/CT. Patients received a median 4 (range 1-4) cycles of 177Lu-DOTATATE (33% with concurrent radiosensitizing chemotherapy) to a median cumulative activity of 27GBq (range 6-43GBq). At median follow-up of 42 months, the median PFS and OS were 23 months (95% CI 18-28 months) and 59 months (95% CI 50-not reached [NR]), respectively. Of 40 patients with RECIST-measurable disease and 39 patients with available 68Ga-DOTATATE PET/CT response categories were: partial response, 20% (95% CI 10-35%) and 44% (95% CI 30-59%); stable disease, 68% (95% CI 52-80%) and 44% (95% CI 30-59%) and progressive disease 12% (95% CI 5-27%) by both, respectively. There was a moderate concordance between response categories by RECIST and 68Ga-DOTATATE PET/CT, weighted Kappa of 0.51 (95% CI 0.21-0.68). Of patients with stable disease by RECIST, those with partial response on 68Ga-DOTATATE PET/CT had longer OS compared to those with no response, NR vs 52 months (95% CI 28-64), HR 0.2 (95% CI 0.1-0.6), p 0.001. Most grade 3/4 AEs were reversible and the most common was lymphopenia (14%) with no incidence of myelodysplasia/leukemia. Conclusion: In patients with advanced progressive lung NET and satisfactory SSR expression, 177Lu-DOTATATE is effective and safe with a high disease control rate and encouraging PFS and OS.

12.
Cancer Imaging ; 21(1): 35, 2021 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-33863390

RESUMO

BACKGROUND: Recent studies reported metabolic uptake in at least one of the evaluated ganglia in 98.5% of patients undergoing 68Ga -PSMA-11 and in 96.9% of patients undergoing 18F-DCFPyL PET/CT examination. We have observed different patterns of ganglion visualization with 18F-DCFPyL compared to 68Ga-PSMA-11. This includes more frequent visualization of cervical and sacral ganglia, which may be attributable to better imaging characteristics with 18F PET imaging. CASE PRESENTATION: This pictorial essay is to illustrate and compare, in the same patient, various representative cases of 68Ga-PSMA-11 and 18F-DCFPyL PET/CT uptake in ganglia at different anatomic locations, with different patterns and distribution of metabolic activity. CONCLUSION: Reading physicians should be aware of the frequently encountered and occasionally different physiologic uptake of 68Ga-PSMA-11 and 18F DCFPyL in different ganglia.


Assuntos
Ácido Edético/análogos & derivados , Gânglios/metabolismo , Oligopeptídeos/metabolismo , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/fisiopatologia , Ácido Edético/metabolismo , Isótopos de Gálio , Radioisótopos de Gálio , Humanos , Masculino
15.
Lancet ; 397(10276): 797-804, 2021 02 27.
Artigo em Inglês | MEDLINE | ID: mdl-33581798

RESUMO

BACKGROUND: Lutetium-177 [177Lu]Lu-PSMA-617 is a radiolabelled small molecule that delivers ß radiation to cells expressing prostate-specific membrane antigen (PSMA), with activity and safety in patients with metastatic castration-resistant prostate cancer. We aimed to compare [177Lu]Lu-PSMA-617 with cabazitaxel in patients with metastatic castration-resistant prostate cancer. METHODS: We did this multicentre, unblinded, randomised phase 2 trial at 11 centres in Australia. We recruited men with metastatic castration-resistant prostate cancer for whom cabazitaxel was considered the next appropriate standard treatment. Participants were required to have adequate renal, haematological, and liver function, and an Eastern Cooperative Oncology Group performance status of 0-2. Previous treatment with androgen receptor-directed therapy was allowed. Men underwent gallium-68 [68Ga]Ga-PSMA-11 and 2-flourine-18[18F]fluoro-2-deoxy-D-glucose (FDG) PET-CT scans. PET eligibility criteria for the trial were PSMA-positive disease, and no sites of metastatic disease with discordant FDG-positive and PSMA-negative findings. Men were randomly assigned (1:1) to [177Lu]Lu-PSMA-617 (6·0-8·5 GBq intravenously every 6 weeks for up to six cycles) or cabazitaxel (20 mg/m2 intravenously every 3 weeks for up to ten cycles). The primary endpoint was prostate-specific antigen (PSA) response defined by a reduction of at least 50% from baseline. This trial is registered with ClinicalTrials.gov, NCT03392428. FINDINGS: Between Feb 6, 2018, and Sept 3, 2019, we screened 291 men, of whom 200 were eligible on PET imaging. Study treatment was received by 98 (99%) of 99 men randomly assigned to [177Lu]Lu-PSMA-617 versus 85 (84%) of 101 randomly assigned to cabazitaxel. PSA responses were more frequent among men in the [177Lu]Lu-PSMA-617 group than in the cabazitaxel group (65 vs 37 PSA responses; 66% vs 37% by intention to treat; difference 29% (95% CI 16-42; p<0·0001; and 66% vs 44% by treatment received; difference 23% [9-37]; p=0·0016). Grade 3-4 adverse events occurred in 32 (33%) of 98 men in the [177Lu]Lu-PSMA-617 group versus 45 (53%) of 85 men in the cabazitaxel group. No deaths were attributed to [177Lu]Lu-PSMA-617. INTERPRETATION: [177Lu]Lu-PSMA-617 compared with cabazitaxel in men with metastatic castration-resistant prostate cancer led to a higher PSA response and fewer grade 3 or 4 adverse events. [177Lu]Lu-PSMA-617 is a new effective class of therapy and a potential alternative to cabazitaxel. FUNDING: Prostate Cancer Foundation of Australia, Endocyte (a Novartis company), Australian Nuclear Science and Technology Organization, Movember, The Distinguished Gentleman's Ride, It's a Bloke Thing, and CAN4CANCER.


Assuntos
Dipeptídeos/uso terapêutico , Compostos Heterocíclicos com 1 Anel/uso terapêutico , Lutécio/uso terapêutico , Antígeno Prostático Específico/sangue , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Radioisótopos/uso terapêutico , Taxoides/uso terapêutico , Administração Intravenosa , Idoso , Antígenos de Superfície/genética , Glutamato Carboxipeptidase II/genética , Humanos , Masculino , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Antígeno Prostático Específico/uso terapêutico , Neoplasias de Próstata Resistentes à Castração/sangue , Neoplasias de Próstata Resistentes à Castração/radioterapia , Resultado do Tratamento
16.
Cancer Imaging ; 21(1): 8, 2021 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-33413689

RESUMO

BACKGROUND: In this study, we investigated the relationship between clinicopathologic factors, BRAFV600E mutation status and [18F] F-fluoro-2-deoxyglucose (FDG) avidity in patients with radioiodine (RAI)-negative recurrent or metastatic differentiated thyroid cancer (DTC). METHODS: From 2015 to 2018 all patients with suspected recurrent or metastatic radioiodine-negative DTC patients who underwent FDG positron emission tomography/computed tomography (PET/CT) were retrospectively reviewed. Suspected lesions on FDG PET/CT were biopsied and underwent BRAFV600E mutation testing by immunohistochemistry and real-time PCR. Tumor size, recurrent versus metastatic disease, histopathologic features including classical type versus aggressive subtypes (poorly differentiated, tall cell, columnar cell, hobnail variants) and BRAFV600E mutation status were correlated with the SUVmax of highest hypermetabolic lesions on FDG PET/CT by the univariate analysis using logistic regression. RESULTS: Sixty-three consecutive patients, 55 (87.3%) female, with median age of 48 (range 17-81) were included. The majority of patients had BRAFV600E mutation and classical subtype, 55/63 (87.3%) and 45/63(71.4%), respectively. Thyroglobulin at the time of suspected recurrence was 262.7 ng/ml (range 16.3-1000) and patients received a median 3 prior RAI treatments. Fifty-four patients (85.7%) had local recurrence. The majority of patients 58/63 (92.1%) had FDG-avid disease on PET/CT. On univariate analysis, tumor size aggressive histopathologic types and distant metastasis are the significant factors for predicting FDG uptake, p = 0.04, p = 0.001 and p = 0.004 respectively. Although FDG uptake of BRAFV600E bearing recurrent/metastatic RAIR DTC lesions was higher than those without the mutation, the difference did not reach statistical significance, SUVmax of 7.11 versus 4.91, respectively, p = 0.2. CONCLUSION: The majority of recurrent or metastatic RAI-negative DTC have BRAFV600E mutation and detectable disease on FDG PET/CT. FDG avidity of the recurrent or metastatic RAI-negative DTC is independently associated with the aggressive histopathologic features.


Assuntos
Adenocarcinoma/diagnóstico por imagem , Recidiva Local de Neoplasia/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Neoplasias da Glândula Tireoide/diagnóstico por imagem , Adenocarcinoma/genética , Adenocarcinoma/patologia , Adulto , Idoso , Feminino , Fluordesoxiglucose F18 , Humanos , Radioisótopos do Iodo , Masculino , Pessoa de Meia-Idade , Mutação , Metástase Neoplásica , Recidiva Local de Neoplasia/genética , Recidiva Local de Neoplasia/patologia , Valor Preditivo dos Testes , Proteínas Proto-Oncogênicas B-raf/genética , Estudos Retrospectivos , Neoplasias da Glândula Tireoide/genética , Neoplasias da Glândula Tireoide/patologia , Adulto Jovem
17.
Eur J Nucl Med Mol Imaging ; 48(1): 204-216, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32572559

RESUMO

PURPOSE: This study aimed to analyse the molecular imaging (MI) phenotype of typical carcinoid (TC) and atypical carcinoid (AC) by 68Ga-DOTATATE (GaTATE) and 18F-FDG (FDG) PET/CT with the emphasis on its potential theranostic implications for peptide receptor radionuclide therapy (PRRT). METHODS: Retrospective review of patients with biopsy-proven TC or AC undergoing both GaTATE and FDG PET/CT at presentation. Based on correlative CT or MRI, positive lesions on either scan were defined by uptake above liver parenchyma. Per patient MI phenotypic pattern was classified as score 1, if all lesions were negative on both scans; score 2, if all were GaTATE positive/FDG negative; score 3, if all lesions were GaTATE positive but some or all were also FDG positive and score 4, if there were any GaTATE negative/FDG positive lesions. Scores 1 and 4 were deemed unsuitable for PRRT. RESULTS: Of 56 patients (median age 66.5 years, 32 female), 22 had TC, and 34 had AC. Distant metastases were seen in 32% of TC and 94% of AC. At a median follow-up of 37 months for TC and 38 months for AC, 100% and 63% were alive, respectively. Median OS for AC was 56 months (95% CI 43, not reached [NR]), and TC was NR. On inter-patient dual-tracer analysis, scores 1, 2, 3 and 4 were 23%, 18%, 36% and 23% in TC and 3%, 15%, 32% and 50% in AC, respectively. In 16 patients (score 2, N = 3; score 3, N = 12; score 4, N = 1) who were treated with PRRT, disease control rate at 3 months and OS were, 85% and 54.6 months (95% CI 44-70), respectively. CONCLUSIONS: TC and AC showed a wide inter-patient phenotypic heterogeneity on GaTATE and FDG with around half of patients (46% TC and 53% AC) having an unsuitable phenotype for PRRT. Dual-tracer MI phenotype can be used to select the most suitable patients for PRRT.


Assuntos
Tumor Carcinoide , Tumores Neuroendócrinos , Compostos Organometálicos , Idoso , Feminino , Fluordesoxiglucose F18 , Radioisótopos de Gálio , Humanos , Imagem Molecular , Fenótipo , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Medicina de Precisão , Estudos Retrospectivos
18.
Intern Med J ; 51(10): 1657-1664, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33314504

RESUMO

BACKGROUND: Because management is very different, it is important to differentiate between small focal insulinomas and diffuse pancreatic dysplasia (nesidioblastosis) in patients with confirmed endogenous hyperinsulinaemic hypoglycaemia (EHH). Most insulinomas highly express glucagon-like peptide-1 receptors enabling positron emission tomography-computed tomography imaging with its radiolabelled analogue; 68 Ga-DOTA-Exendin-4 (Exendin). AIM: To determine: (i) the utility of Exendin in EHH patients in a clinical setting; and (ii) whether the degree of Exendin uptake differentiates non-insulinoma pancreatogenous hypoglycaemia syndrome (NIPHS) from post-gastric bypass hypoglycaemia (PGBH). METHODS: This retrospective study reviewed the clinical, biochemistry and prior imaging findings in confirmed EHH patients referred for Exendin. Accuracy of Exendin was based on surgical findings and treatment outcomes. Finally, average Exendin uptake (SUVmax) of five PGBH studies was compared with the SUVmax of a key NIPHS case report. RESULTS: Twenty of 25 consecutive patients had confirmed EHH. Exendin located insulinomas in eight of nine patients enabling successful surgical excision with rapid and durable cure. Exendin correctly identified diffuse nesidioblastosis in two of three cases requiring partial pancreatectomy for hypoglycaemia control. All three relapsed within 1.7 years with one needing completion pancreatectomy. Establishing the cause in the remainder relied on other investigations, clinical correlation and response to empirical treatment. Finally, Exendin SUVmax could not distinguish between NIPHS and PGBH. CONCLUSION: In EHH patients, Exendin accurately identifies the site of insulinoma and thereby differentiates it from nesidioblastosis but negative findings should not be ignored. Exendin is unlikely to differentiate between normal pancreatic uptake, NIPHS and PGBH.


Assuntos
Hipoglicemia , Insulinoma , Nesidioblastose , Neoplasias Pancreáticas , Exenatida , Humanos , Hipoglicemia/diagnóstico por imagem , Hipoglicemia/etiologia , Insulinoma/diagnóstico por imagem , Insulinoma/cirurgia , Neoplasias Pancreáticas/complicações , Neoplasias Pancreáticas/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Estudos Retrospectivos
19.
BMJ Open ; 10(12): e042465, 2020 12 10.
Artigo em Inglês | MEDLINE | ID: mdl-33303468

RESUMO

BACKGROUND: In the curative-intent treatment of locally advanced lung cancer, significant morbidity and mortality can result from thoracic radiation therapy. Symptomatic radiation pneumonitis occurs in one in three patients and can lead to radiation-induced fibrosis. Local failure occurs in one in three patients due to the lungs being a dose-limiting organ, conventionally restricting tumour doses to around 60 Gy. Functional lung imaging using positron emission tomography (PET)/CT provides a geographic map of regional lung function and preclinical studies suggest this enables personalised lung radiotherapy. This map of lung function can be integrated into Volumetric Modulated Arc Therapy (VMAT) radiotherapy planning systems, enabling conformal avoidance of highly functioning regions of lung, thereby facilitating increased doses to tumour while reducing normal tissue doses. METHODS AND ANALYSIS: This prospective interventional study will investigate the use of ventilation and perfusion PET/CT to identify highly functioning lung volumes and avoidance of these using VMAT planning. This single-arm trial will be conducted across two large public teaching hospitals in Australia. Twenty patients with stage III non-small cell lung cancer will be recruited. All patients enrolled will receive dose-escalated (69 Gy) functional avoidance radiation therapy. The primary endpoint is feasibility with this achieved if ≥15 out of 20 patients meet pre-defined feasibility criteria. Patients will be followed for 12 months post-treatment with serial imaging, biomarkers, toxicity assessment and quality of life assessment. DISCUSSION: Using advanced techniques such as VMAT functionally adapted radiation therapy may enable safe moderate dose escalation with an aim of improving local control and concurrently decreasing treatment related toxicity. If this technique is proven feasible, it will inform the design of a prospective randomised trial to assess the clinical benefits of functional lung avoidance radiation therapy. ETHICS AND DISSEMINATION: This study was approved by the Peter MacCallum Human Research Ethics Committee. All participants will provide written informed consent. Results will be disseminated via publications. TRIALS REGISTRATION NUMBER: NCT03569072; Pre-results.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Austrália , Carcinoma Pulmonar de Células não Pequenas/diagnóstico por imagem , Carcinoma Pulmonar de Células não Pequenas/radioterapia , Estudos de Viabilidade , Radioisótopos de Gálio , Humanos , Pulmão/diagnóstico por imagem , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/radioterapia , Perfusão , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Tomografia por Emissão de Pósitrons , Estudos Prospectivos , Qualidade de Vida , Planejamento da Radioterapia Assistida por Computador , Tomografia Computadorizada por Raios X
20.
J Nucl Med ; 61(11): 1553-1559, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32887755

RESUMO

Although 18F-FDG PET/CT is widely available and is increasingly being used to monitor response to immunotherapy and simultaneously identify immune-related adverse events, there are several challenges in interpreting the results of this investigation, especially early in the course of treatment. It also has limited utility in selecting the optimal type of immunotherapy. As knowledge about immune contexture increases, new targets that may be amenable to imaging are being defined. These exciting advances, coupled with increasingly sophisticated methods for generating radiopharmaceuticals, provide the potential for either replacing or complementing 18F-FDG PET/CT in the selection and monitoring of immunotherapy. Approaches include imaging specific characteristics of immune cell infiltrates or aspects of the tumor microenvironment that are known to be associated with suppression of the innate and adaptive immune response. Following a large body of preclinical work, promising agents that are entering into early clinical evaluation are discussed. We suggest a speculative algorithm as to how these might be used in routine practice, subject to validation in clinical trials.


Assuntos
Fluordesoxiglucose F18 , Inibidores de Checkpoint Imunológico/uso terapêutico , Neoplasias/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Compostos Radiofarmacêuticos , Linfócitos T CD8-Positivos/imunologia , Humanos , Imunoterapia , Neoplasias/tratamento farmacológico , Neoplasias/imunologia , Microambiente Tumoral
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