Positron emission tomography of tumour [18F]fluoroestradiol uptake in patients with acquired hormone-resistant metastatic breast cancer prior to oestradiol therapy

Purpose Whereas anti-oestrogen therapy is widely applied to treat oestrogen receptor (ER) positive breast cancer, paradoxically, oestrogens can also induce tumour regression. Upregulation of ER expression is a marker for oestrogen hypersensitivity. We, therefore, performed an exploratory study to evaluate positron emission tomography (PET) with the tracer 16 alpha-[F-18] fluoro-17 beta-oestradiol (F-18-FES) as potential marker to select breast cancer patients for oestradiol therapy. Methods Eligible patients had acquired endocrine-resistant metastatic breast cancer that progressed after >= 2 lines of endocrine therapy. All patients had prior ER-positive histology. Treatment consisted of oestradiol 2 mg, three times daily, orally. Patients underwent F-18-FES-PET/CT imaging at baseline. Tumour F-18-FES-uptake was quantified for a maximum of 20 lesions and expressed as maximum standardised uptake value (SUVmax). CT-scan was repeated every 3 months to evaluate treatment response. Clinical benefit was defined as time to radiologic or clinical progression >= 24 weeks. Results F-18-FES uptake, quantified for 255 lesions in 19 patients, varied greatly between lesions (median 2.8; range 0.6-24.3) and between patients (median 2.5; range 1.1-15.5). Seven (37 %) patients experienced clinical benefit of oestrogen therapy, eight progressed (PD), and four were non-evaluable due to side effects. The positive and negative predictive value PPV/NPV) of F-18-FES-PET for response to treatment were 60 % (95 % CI: 31-83 %) and 80 % (95 % CI: 38-96 %), respectively, using SUVmax >1.5. Conclusion F-18-FES-PET may aid identification of patients with acquired antihormone resistant breast cancer that are unlikely to benefit from oestradiol therapy

Insights on physical behavior while working from home:An ecological momentary assessment study

Ever since the COVID-19 pandemic, working from home (WFH) has emerged as a common alternative work environment, but the possible influence on daily physical behavior (PB) (i.e., physical activity (PA), sedentary behavior (SB)) remains unclear. This study aimed to examine daily associations between PB and the work environment (i.e., WFH, working at the office (WAO)), as well as to explore and identify patterns of PB within each work environment. An observational study using a dual-accelerometer system to continuously assess PB for at least 5 days was conducted. The sample consisted of 55 participants providing 276 days of assessment. Additional demographic, contextual, and psychological variables were measured via baseline questionnaire and several smartphone prompts per day. To analyze the effects of the work environment on PB, multilevel analyses were conducted. For the identification of patterns within each work environment, latent class trajectory modelling was applied. Associations between the work environment and various PA parameters were found, indicating that WFH has a negative effect on MVPA time, steps, and physical activity intensity (MET), but a positive effect on short PA bouts (≤5 min). No associations between the work environment and any SB parameter (i.e., SB time, SB breaks, SB bouts) were found. Latent class trajectory modelling revealed three MVPA patterns for days WFH, and two patterns for days WAO. Given the growing prevalence of WFH and the positive health effects associated with MVPA, daily-tailored solutions to enhance MPVA while WFH are urgently needed.</p

Insights on physical behavior while working from home: An ecological momentary assessment study

Ever since the COVID-19 pandemic, working from home (WFH) has emerged as a common alternative work environment, but the possible influence on daily physical behavior (PB) (i.e., physical activity (PA), sedentary behavior (SB)) remains unclear. This study aimed to examine daily associations between PB and the work environment (i.e., WFH, working at the office (WAO)), as well as to explore and identify patterns of PB within each work environment. An observational study using a dual-accelerometer system to continuously assess PB for at least 5 days was conducted. The sample consisted of 55 participants providing 276 days of assessment. Additional demographic, contextual, and psychological variables were measured via baseline questionnaire and several smartphone prompts per day. To analyze the effects of the work environment on PB, multilevel analyses were conducted. For the identification of patterns within each work environment, latent class trajectory modelling was applied. Associations between the work environment and various PA parameters were found, indicating that WFH has a negative effect on MVPA time, steps, and physical activity intensity (MET), but a positive effect on short PA bouts (≤5 min). No associations between the work environment and any SB parameter (i.e., SB time, SB breaks, SB bouts) were found. Latent class trajectory modelling revealed three MVPA patterns for days WFH, and two patterns for days WAO. Given the growing prevalence of WFH and the positive health effects associated with MVPA, daily-tailored solutions to enhance MPVA while WFH are urgently needed

Mitigation of noise-induced bias of PET radiomic features

INTRODUCTION: One major challenge in PET radiomics is its sensitivity to noise. Low signal-to-noise ratio (SNR) affects not only the precision but also the accuracy of quantitative metrics extracted from the images resulting in noise-induced bias. This phantom study aims to identify the radiomic features that are robust to noise in terms of precision and accuracy and to explore some methods that might help to correct noise-induced bias. METHODS: A phantom containing three 18F-FDG filled 3D printed inserts, reflecting heterogeneous tracer uptake and realistic tumor shapes, was used in the study. The three different phantom inserts were filled and scanned with three different tumor-to-background ratios, simulating a total of nine different tumors. From the 40-minute list-mode data, ten frames each for 5 s, 10 s, 30 s, and 120 s frame duration were reconstructed to generate images with different noise levels. Under these noise conditions, the precision and accuracy of the radiomic features were analyzed using intraclass correlation coefficient (ICC) and similarity distance metric (SDM) respectively. Based on the ICC and SDM values, the radiomic features were categorized into four groups: poor, moderate, good, and excellent precision and accuracy. A "difference image" created by subtracting two statistically equivalent replicate images was used to develop a model to correct the noise-induced bias. Several regression methods (e.g., linear, exponential, sigmoid, and power-law) were tested. The best fitting model was chosen based on Akaike information criteria. RESULTS: Several radiomic features derived from low SNR images have high repeatability, with 68% of radiomic features having ICC ≥ 0.9 for images with a frame duration of 5 s. However, most features show a systematic bias that correlates with the increase in noise level. Out of 143 features with noise-induced bias, the SDM values were improved based on a regression model (53 features to excellent and 67 to good) indicating that the noise-induced bias of these features can be, at least partially, corrected. CONCLUSION: To have a predictive value, radiomic features should reflect tumor characteristics and be minimally affected by noise. The present study has shown that it is possible to correct for noise-induced bias, at least in a subset of the features, using a regression model based on the local image noise estimates

Treatment costs and quality of life with granulocyte-macrophage colony-stimulating factor in patients with antineoplastic therapy-related febrile neutropenia:Results of a randomised placebo-controlled trial

This study examined the costs of treatment of, and quality of life in, patients with antineoplastic therapy-induced neutropenic fever who were treated with antibacterials, with or without granulocyte-macrophage colony-stimulating factor (GM-CSF). Patients with haematological malignancies (n = 47) or solid tumours (n = 87) who had severe neutropenia (neutrophil count &lt;0.5 x 109/L) and fever (&gt;38.5°C once, or &gt;38°C twice, in a 12-hour observation period) were randomised to receive subcutaneous GM-CSF 5 μg/kg/day (n = 65) or placebo (n = 69) in conjunction with broad-spectrum antibacterials. GM-CSF enhanced neutrophil recovery compared with placebo. Median neutrophil counts at day 4 were 2.9 (range 0 to 25) x 109/L in the GM-CSF arm and 1.3 (range 0 to 9) x 109/L in the placebo group (p &lt; 0.001). No significant difference was observed with regard to median days with neutrophil count ≤1.0 x 109/L or in time to resolution of fever. Quality-of-life scores in 90 patients demonstrated significant differences in favour of the placebo group. The results for the oncology and haematology patients were similar to the results for the total group. patients in the GM-CSF and placebo groups had a mean hospital stay of 7.25 and 8.33 days, respectively. Hospital costs were higher for the GM-CSF-treated patients when GM-CSF was included in the price [mean costs: GM-CSF arm $US5177 vs placebo arm$US4178 (p &lt; 0.05; 1992 values)l. The haematology patients stayed longer in hospital than the oncology patients, resulting in higher total costs for the former group. These results indicate that GM-CSF does not affect the number of days required for resolution of fever or the hospitalisation period for this patient group, and does not provide a cost-effective contribution to the treatment of these patients. Sensitivity analyses indicate that GM-CSF would produce savings if the duration of hospitalisation with GM-CSF was ≤76.5% of that in the placebo group.</p

Molecular Imaging of PD-L1 Expression and Dynamics with the Adnectin-Based PET Tracer F-18-BMS-986192

F-18-BMS-986192, an adnectin-based human programmed cell death ligand 1 (PD-L1) tracer, was developed to noninvasively determine whole-body PD-L1 expression by PET. We evaluated the usability of F-18-BMS-986192 PET to detect different PD-L1 expression levels and therapy-induced changes in PD-L1 expression in tumors. Methods: In vitro binding assays with F-18-BMS-986192 were performed on human tumor cell lines with different total cellular and membrane PD-L1 protein expression levels. Subsequently, PET imaging was performed on immunodeficient mice xenografted with these cell lines. The mice were treated with interferon gamma (IFN gamma) intraperitoneally for 3 d or with the mitogen-activated protein kinase kinase inhibitor selumetinib by oral gavage for 24 h. Afterward, F-18-BMS-986192 was administered intravenously, followed by a 60-min dynamic PET scan. Tracer uptake was expressed as percentage injected dose per gram of tissue. Tissues were collected to evaluate ex vivo tracer biodistribution and to perform flow cytometric, Western blot, and immunohistochemical tumor analyses. Results: F-18-BMS-986192 uptake reflected PD-L1 membrane levels in tumor cell lines, and tumor tracer uptake in mice was associated with PD-L1 expression measured immunohistochemically. In vitro IFN gamma treatment increased PD-L1 expression in the tumor cell lines and caused up to a 12-fold increase in tracer binding. In vivo, IFN gamma affected neither PD-L1 tumor expression measured immunohistochemically nor F-18-BMS-986192 tumor uptake. In vitro, selumetinib downregulated cellular and membrane levels of PD-L1 in tumor cells by 50% as measured by Western blotting and flow cytometry. In mice, selumetinib lowered cellular, but not membrane, PD-L1 levels of tumors, and consequently, no treatment-induced change in F-18-BMS-986192 tumor uptake was observed. Conclusion: F-18-BMS-986192 PET imaging allows detection of membrane-expressed PD-L1 as soon as 60 min after tracer injection. The tracer can discriminate a range of tumor cell PD-L1 membrane expression levels

Reconsider radiation exposure from imaging during immune checkpoint inhibitor trials to reduce risk of secondary cancers in long-term survivors?

Immune checkpoint inhibitors (ICI) have improved outcomes for patients with advanced cancers, and results in increasing numbers of long-term survivors. For registration studies, progression-free survival and disease-free survival often serve as primary endpoints. This requires repeated computed tomography (CT) scans for tumour imaging which might lead to major radiation exposure. To determine this, all immune checkpoint inhibitors trials that led to FDA approval were retrieved up to July 29, 2019. From the available protocols, imaging modalities and schedules used in each trial were identified. The anticipated cumulative number of scans made after 1, 3, 5, and 10 years study participation were calculated. The percentage of lifetime attributable cancer risk was calculated using the Biological Effects of Ionizing Radiation VII report. Fifty-one trials were identified, from which 39 protocols were retrieved. Four were adjuvant trials. All protocols required repeated chest-abdomen imaging and specified CT scans as preferred imaging modality. Median calculated cumulative numbers of chest-abdomen CT scans after 1, 3, 5, and 10 years study participation were 7, 16, 24 and 46, respectively. For ages 20-70 years at study entry, the average lifetime attributable cancer risk after 1 year of study participation ranged from 1.11 to 0.40% for men and from 1.87 to 0.46% for women. At 10 years study participation, this risk increased to a range of 5.91 to 1.96% for men and 9.64 to 2.32% for women. Given high imaging radiation exposure for long-term survivors in current ICI trials an adaptive imaging interval and imaging termination rules should be considered for long-term survivors

Development and evaluation of interleukin-2 derived radiotracers for PET imaging of T-cells in mice

Recently, N-(4-18F-fluorobenzoyl)-interleukin-2 (18F-FB-IL2) was introduced as a PET tracer for T cell imaging. However, production is complex and time-consuming. Therefore, we developed 2 radiolabeled IL2 variants, namely aluminum 18F-fluoride-(restrained complexing agent)-IL2 (18F-AlF-RESCA-IL2) and 68Ga-gallium-(1,4,7-triazacyclononane-4,7-diacetic acid-1-glutaric acid)-IL2 (68Ga-Ga-NODAGA-IL2), and compared their in vitro and in vivo characteristics with 18F-FB-IL2. Methods: Radiolabeling of 18F-AlF-RESCA-IL2 and 68Ga-Ga-NODAGA-IL2 was optimized, and stability was evaluated in human serum. Receptor binding was studied with activated human peripheral blood mononuclear cells (hPBMCs). Ex vivo tracer biodistribution in immunocompetent BALB/cOlaHsd (BALB/c) mice was performed at 15, 60, and 90 min after tracer injection. In vivo binding characteristics were studied in severe combined immunodeficient (SCID) mice inoculated with activated hPBMCs in Matrigel. Tracer was injected 15 min after hPBMC inoculation, and a 60-min dynamic PET scan was acquired, followed by ex vivo biodistribution studies. Specific uptake was determined by coinjection of tracer with unlabeled IL2 and by evaluating uptake in a control group inoculated with Matrigel only. Results:68Ga-Ga-NODAGA-IL2 and 18F-AlF-RESCA-IL2 were produced with radiochemical purity of more than 95% and radiochemical yield of 13.1% ± 4.7% and 2.4% ± 1.6% within 60 and 90 min, respectively. Both tracers were stable in serum, with more than 90% being intact tracer after 1 h. In vitro, both tracers displayed preferential binding to activated hPBMCs. Ex vivo biodistribution studies on BALB/c mice showed higher uptake of 18F-AlF-RESCA-IL2 than of 18F-FB-IL2 in liver, kidney, spleen, bone, and bone marrow. 68Ga-Ga-NODAGA-IL2 uptake in liver and kidney was higher than 18F-FB-IL2 uptake. In vivo, all tracers revealed uptake in activated hPBMCs in SCID mice. Low uptake was seen after a blocking dose of IL2 and in the Matrigel control group. In addition, 18F-AlF-RESCA-IL2 yielded the highest-contrast PET images of target lymph nodes. Conclusion: Production of 18F-AlF-RESCA-IL2 and 68Ga-Ga-NODAGA-IL2 is simpler and faster than that of 18F-FB-IL2. Both tracers showed good in vitro and in vivo characteristics, with high uptake in lymphoid tissue and hPBMC xenografts

Analyzing the Estrogen Receptor Status of Liver Metastases with [F-18]-FES-PET in Patients with Breast Cancer

Background: Positron emission tomography (PET) with 16α-[18F]-fluoro-17β-estradiol ([18F]-FES) can visualize estrogen receptor (ER) expression, but it is challenging to determine the ER status of liver metastases, due to high physiological [18F]-FES uptake. We evaluated whether [18F]-FES-PET can be used to determine the ER status of liver metastases, using corresponding liver biopsies as the gold standard. Methods: Patients with metastatic breast cancer (n = 23) were included if they had undergone a [18F]-FES-PET, liver metastasis biopsy, CT-scan, and [18F]-FDG-PET. [18F]-FES-PET scans were assessed by visual and quantitative analysis, tracer uptake was correlated with ER expression measured by immunohistochemical staining and the effects of region-of-interest size and background correction were determined. Results: Visual analysis allowed ER assessment of liver metastases with 100% specificity and 18% sensitivity. Quantitative analysis improved the sensitivity. Reduction of the region-of-interest size did not further improve the results, but background correction improved ER assessment, resulting in 83% specificity and 77% sensitivity. Using separate thresholds for ER+ and ER− metastases, positive and negative predictive values of 100% and 75%, respectively, could be obtained, although 30% of metastases remained inconclusive. Conclusion: In the majority of liver metastases, ER status can be determined with [18F]-FES-PET if background correction and separate thresholds are applied