A randomised trial of [18F]PSMA-1007-PET/CT versus NaF-PET/CT for staging primary prostate cancer: A trial protocol.

Background: Prostate-specific membrane antigen (PSMA)-positron emission tomography/contrast-enhanced computed tomography (PET/CT) is a sensitive imaging modality for prostate cancer (PCa). Due to lack of knowledge of the patient benefit, PSMA-PET/CT is not yet recommended in the European guidelines for staging and treatment planning of patients with newly diagnosed PCa. We will investigate the potential difference in progression-free survival (PFS) and quality of life (QoL) of using PSMA-PET/CT versus sodium fluoride (NaF)-PET/CT for staging and treatment planning in patients with newly diagnosed PCa. Study Design: This is a prospective randomised controlled multicentre trial carried out at three centres in the Region of Southern Denmark. Endpoints: The primary endpoint is PFS. Secondary endpoints are residual disease, stage migration, impact on treatment strategies, stage distribution, QoL and diagnostic accuracy measures. Patients and Methods: Patients eligible for the study have newly diagnosed unfavourable intermediate- or high-risk PCa. A total of 448 patients will be randomised 1:1 into two groups: (A) a control group staged with Na[18F]F-PET/CT and (B) an intervention group staged with [18F]PSMA-1007-PET/CT. A subgroup in the intervention group will have a supplementary blinded Na[18F]F-PET/CT performed for the purpose of performing accuracy analyses. QoL will be assessed at baseline and with regular intervals (3-12 months) during the study period. Treatment decisions are achieved at multidisciplinary team conferences based on the results of the respective scans and according to current Danish guidelines. Trial Registration: The Regional Committees on Health Research Ethics for Southern Denmark (S-20190161) and the Danish Medicines Agency (EudraCT Number 2021-000123-12) approved the study, and it has been registered on clinicaltrials.gov (Record 2020110469).

Automated quantification of PET/CT skeletal tumor burden in prostate cancer using artificial intelligence: The PET index.

PURPOSE: Consistent assessment of bone metastases is crucial for patient management and clinical trials in prostate cancer (PCa). We aimed to develop a fully automated convolutional neural network (CNN)-based model for calculating PET/CT skeletal tumor burden in patients with PCa. METHODS: A total of 168 patients from three centers were divided into training, validation, and test groups. Manual annotations of skeletal lesions in [18F]fluoride PET/CT scans were used to train a CNN. The AI model was evaluated in 26 patients and compared to segmentations by physicians and to a SUV 15 threshold. PET index representing the percentage of skeletal volume taken up by lesions was estimated. RESULTS: There was no case in which all readers agreed on prevalence of lesions that the AI model failed to detect. PET index by the AI model correlated moderately strong to physician PET index (mean r = 0.69). Threshold PET index correlated fairly with physician PET index (mean r = 0.49). The sensitivity for lesion detection was 65-76% for AI, 68-91% for physicians, and 44-51% for threshold depending on which physician was considered reference. CONCLUSION: It was possible to develop an AI-based model for automated assessment of PET/CT skeletal tumor burden. The model's performance was superior to using a threshold and provides fully automated calculation of whole-body skeletal tumor burden. It could be further developed to apply to different radiotracers. Objective scan evaluation is a first step toward developing a PET/CT imaging biomarker for PCa skeletal metastases.

Improved stratification of stage-specific survival for cervical uterine cancer by integrating FDG-PET/CT and MRI for lymph node staging in 2018 FIGO classification.

OBJECTIVE: Staging carcinoma of the uterine cervix (CCU) by FIGO-2018 suggests stage migration of FIGO-2009 stage I-III patients with lymph node metastasis into FIGO-2018 stage IIIC. We aimed to investigate the prognostic value of lymph node metastases identified by imaging. METHODS: We enrolled all patients with biopsy-verified CCU from 2007 to 2016 at Odense University Hospital, Denmark. FDG-PET/CT and MRI were performed before clinical examination in general anesthesia. Disease-specific mortality was compared between women with lymph node-positive and lymph node-negative imaging. RESULTS: In total, 488 patients underwent clinical staging according to FIGO-2009. Lymph node-positive imaging was identified in 146 (30%) patients: 0/36 (0%) in stage IA, 22/195 (11%) in IBI, 14/30 (47%) in IB2, 70/164 (43%) in II and 40/63 (63%) in III. The 5-year cumulative incidence of death due to CCU lymph node-negative vs. lymph node-positive patients was 0.8% vs. 7.1% (p = 0.034) in stage IBI, 0% vs. 34.5% (p = 0.003) in stage IB2, 15.1% vs. 41.4% (p < 0.0001) in stage II, and 33.3% vs. 46.6% (p = 0.28) in stage III by FIGO-2009. CONCLUSIONS: One of three women with FIGO-2009 stage I-III CCU had suspected lymph node metastasis on imaging and is upstaged to stage IIIC according to FIGO-2018. The cancer-specific mortality by CCU was significantly lower in the lymph node-negative women stages IBI-II, thus supporting stage migration due to suspected lymph node metastasis. However, the exact prognostic value within stage IIIC is challenged, and future revision of FIGO stages may include new sub-stages.

From FIGO-2009 to FIGO-2018 in women with early-stage cervical cancer; Does the revised staging reflect risk groups?

OBJECTIVES: We aimed to evaluate if the revised staging according to FIGO-2018 in early-stage cervical cancer correctly predicts the risk for nodal metastases. METHODS: We reallocated 245 women with early-stage cervical cancer from FIGO-2009 to FIGO-2018 stages using data from a national, prospective cohort study on sentinel lymph node (SLN) mapping. We used univariate and multivariate binary regression models to investigate the association between FIGO-2018 stages, tumor characteristics, and nodal metastases. RESULTS: Stage migration occurred in 54.7% (134/245) (95% CI 48.2-61.0), due to tumor size or depth of invasion (71.6%, 96/134) and nodal metastases (28.4%, 38/134). Imaging preoperatively upstaged 7.3% (18/245); seven had nodal metastatic disease on final pathology. Upstaging occurred in 49.8% (122/245) (95% CI 43.4-56.2%) and downstaging to FIGO-2018 IA stages in 4.9% (12/245) (95% CI 2.6-8.4). The tumor size ranged from 3.0-19.0 mm in women with FIGO-2018 IA tumor characteristics, and none of the 14 women had nodal metastases. In multivariate analysis, risk factors significantly associated with nodal metastases were FIGO-2018 ≥ IB2 (RR 5.01, 95% CI 2.30-10.93, p < 0.001), proportionate depth of invasion >2/3 (RR 1.88, 95% CI 1.05-3.35, p = 0.033), and lymphovascular space invasion (RR 5.56, 95% CI 2.92-10.62, p < 0.001). CONCLUSIONS: The FIGO-2018 revised staging system causes stage migration for a large proportion of women with early-stage cervical cancer. Women who were downstaged to FIGO-2018 IA stages did not have nodal metastatic disease. The attention on depth of invasion rather than horizontal dimension seems to correctly reflect the risk of nodal metastases.

Higher Interrater Agreement of FDG-PET/CT than Bone Scintigraphy in Diagnosing Bone Recurrent Breast Cancer.

The purpose was to investigate the interrater agreement of FDG-PET/CT and bone scintigraphy for diagnosing bone recurrence in breast cancer patients. A total of 100 women with suspected recurrence of breast cancer underwent planar whole-body bone scintigraphy with [99mTc]DPD and FDG-PET/CT. Scans were evaluated independently by experienced nuclear medicine physicians and the results for one modality were blinded to the other. Images were visually interpreted using a 4-point assessment scale (0 = no metastases, 1 = probably no metastases, 2 = probably metastases, 3 = definite metastases). Out of 100 women, 22 (22%) were verified with distant recurrence, 18 of these had bone involvement. The proportions of agreement between readers were 93% (86.3-96.6) for bone recurrence with FDG-PET/CT and 47% (37.5-56.7) for bone recurrence with planar bone scintigraphy. The strengths of agreement between readers for diagnosing bone recurrence was 'almost perfect' with FDG-PET/CT and was 'fair' with planar bone scintigraphy according to Cohen's kappa value of 0.82 (0.70-0.95) and 0.28 (0.18-0.39), respectively. Interrater agreement yielded improved reproducibility with FDG-PET/CT versus with bone scintigraphy when diagnosing recurrence with bone metastasis in this patient cohort.

Interrater Agreement and Reliability of PERCIST and Visual Assessment When Using 18F-FDG-PET/CT for Response Monitoring of Metastatic Breast Cancer.

Response evaluation at regular intervals is indicated for treatment of metastatic breast cancer (MBC). FDG-PET/CT has the potential to monitor treatment response accurately. Our purpose was to: (a) compare the interrater agreement and reliability of the semi-quantitative PERCIST criteria to qualitative visual assessment in response evaluation of MBC and (b) investigate the intrarater agreement when comparing visual assessment of each rater to their respective PERCIST assessment. We performed a retrospective study on FDG-PET/CT in women who received treatment for MBC. Three specialists in nuclear medicine categorized response evaluation by qualitative assessment and standardized one-lesion PERCIST assessment. The scans were categorized into complete metabolic response, partial metabolic response, stable metabolic disease, and progressive metabolic disease. 37 patients with 179 scans were included. Visual assessment categorization yielded moderate agreement with an overall proportion of agreement (PoA) between raters of 0.52 (95% CI 0.44-0.66) and a Fleiss kappa estimate of 0.54 (95% CI 0.46-0.62). PERCIST response categorization yielded substantial agreement with an overall PoA of 0.65 (95% CI 0.57-0.73) and a Fleiss kappa estimate of 0.68 (95% CI 0.60-0.75). The difference in PoA between overall estimates for PERCIST and visual assessment was 0.13 (95% CI 0.06-0.21; p = 0.001), that of kappa was 0.14 (95% CI 0.06-0.21; p < 0.001). The overall intrarater PoA was 0.80 (95% CI 0.75-0.84) with substantial agreement by a Fleiss kappa of 0.74 (95% CI 0.69-0.79). Semi-quantitative PERCIST assessment achieved significantly higher level of overall agreement and reliability compared with qualitative assessment among three raters. The achieved high levels of intrarater agreement indicated no obvious conflicting elements between the two methods. PERCIST assessment may, therefore, give more consistent interpretations between raters when using FDG-PET/CT for response evaluation in MBC.

FDG-PET/CT for Response Monitoring in Metastatic Breast Cancer: Today, Tomorrow, and Beyond.

While current international guidelines include imaging of the target lesion for response monitoring in metastatic breast cancer, they do not provide specific recommendations for choice of imaging modality or response criteria. This is important as clinical decisions may vary depending on which imaging modality is used for monitoring metastatic breast cancer. FDG-PET/CT has shown high accuracy in diagnosing metastatic breast cancer, and the Positron Emission Tomography Response Criteria in Solid Tumors (PERCIST) have shown higher predictive values than the CT-based Response Evaluation Criteria in Solid Tumors (RECIST) for prediction of progression-free survival. No studies have yet addressed the clinical impact of using different imaging modalities or response evaluation criteria for longitudinal response monitoring in metastatic breast cancer. We present a case study of a patient with metastatic breast cancer who was monitored first with conventional CT and then with FDG-PET/CT. We retrospectively applied PERCIST to evaluate the longitudinal response to treatment. We used the one-lesion PERCIST model measuring SULpeak in the hottest metastatic lesion on consecutive scans. This model provides a continuous variable that allows graphical illustration of disease fluctuation along with response categories. The one-lesion PERCIST approach seems able to reflect molecular changes and has the potential to support clinical decision-making. Prospective clinical studies addressing the clinical impact of PERCIST in metastatic breast cancer are needed to establish evidence-based recommendations for response monitoring in this disease.

Diagnostic manifestations of total hemispheric glucose metabolism ratio in neuronal network diaschisis: diagnostic implications in Alzheimer's disease and mild cognitive impairment.

PURPOSE: We tested the hypothesis that lateralized hemispheric glucose metabolism may have diagnostic implications in Alzheimer's disease (AD) and mild cognitive impairment (MCI). METHODS: We performed FDG-PET/CT in 23 patients (mean age 63.7 years, range 50-78, 17 females) diagnosed with AD (n = 15) or MCI (n = 8) during a six-month period in 2014. Ten neurologically healthy individuals (HIs) (mean age 62.5 years, range 43-75, 5 females) served as controls. A neuroimaging expert provided visual assessment of diaschisis. The total hemispheric glucose metabolism ratio (THGr) was calculated, and with area-under the curve of receiver operating characteristics (AUC-ROC) we generated a "Network Diaschisis Test (NDT)". RESULTS: The qualitative detection of cerebral (Ce) and cerebellar (Cb) diaschisis was 7/15 (47%), 0/8 (0%), and 0/10 (0%) in AD, MCI, and HI groups, respectively. Median cerebral THGr was 0.68 (range 0.43-0.99), 0.86 (range 0.64-0.98), and 0.95 (range 0.65-1.00) for AD, MCI, and HI groups, respectively (p = 0.04). Median cerebellar THGr was, respectively, 0.70 (range 0.18-0.98), 0.70 (range 0.48-0.81), and 0.84 (range 0.75-0.96) (p = 0.0138). A positive NDT yielded a positive predictive value of 100% for the presence of AD or MCI and a 86% negative predictive value for healthy brain. Moreover, the diagnostic manifestation of THGr between MCI and AD led to a positive predictive value of 100% for AD, but a negative predictive value of 42.9% for MCI. CONCLUSION: Patients with AD or MCI had more pronounced diaschisis, lateralized hemispheric glucose metabolism and lower THGr compared to healthy controls. The NDT distinguished AD and MCI patients from HIs, and AD from MCI patients with a high positive predictive value and moderate and low negative predictive values. THGr can be a straightforward source of investigating neuronal network diaschisis in AD and MCI and in other cerebral diseases, across institutions.