Needs and Demands for e-Mental Health Interventions in Individuals with Overweight and Obesity: User-Centred Design Approach

INTRODUCTION

Several studies indicate an association between mental disorders and overweight or obesity. E-Mental health interventions offer an effective way to overcome barriers to health care access for individuals with overweight and obesity. The objective of this study was to examine the needs and demands for e-mental health interventions among individuals with overweight and obesity.

METHODS

A cross-sectional study was conducted from 2020 to 2021 in Germany. A total of 643 participants were recruited through specialized social media platforms and the Alfried-Krupp hospital in Essen, Germany. Sociodemographic and medical data were analysed, as well as data on depressive symptoms and on the needs and demands for e-mental health interventions.

RESULTS

Contact with and recommendation by experts appear to be key aspects in the acceptance and use of e-mental health interventions. In summary, most participants preferred a 20-30-min weekly session via smartphone over a 4-month period. The highest preference in terms of features included practicing coping skills and being provided with information; in regard to desired topics, nutrition consultation, quality of life, and adapting to new life situations were considered most important.

DISCUSSION

e-Mental health interventions can be highly beneficial for individuals, especially when developed through a user-centred design approach. The results of the study indicate which content and design are preferred and, thereby, provide valuable information for consideration when developing a tailored e-mental health intervention.

Social problem solving and trait socioemotional abilities in ambulatory stroke patients

INTRODUCTION

Stroke has been associated with sociocognitive impairment, so far well documented for emotion recognition and Theory of Mind. However, more complex abilities, such as social problem solving, which directly facilitate appropriate behavior in social situations have been neglected in previous research.

METHOD

The present study aimed to address this gap by focusing on performance-based social problem solving abilities and self-reported socioemotional abilities (i.e., empathy and alexithymia) in outpatient stroke patients (n = 36) compared to a group of healthy controls (n = 36) equivalent on age, gender, and education. In further analyses, potential lateralization effects and correlations between social problem solving/socioemotional functioning and demographic and clinical data were investigated.

RESULTS

In the main analyses, patients were impaired in their ability to freely generate appropriate solutions for challenging interpersonal situations depicted in written scenarios but performed on a comparable level as healthy controls when they had to choose the optimal solution presented amidst a range of less optimal options. While showing difficulty in identifying the awkward elements in the scenarios, the patient group nevertheless rated the degree of discomfort attributed to these elements on a level comparable to the control group. On the self-report measures, stroke patients reported overall higher degrees of alexithymia (i.e., an inability to describe and identify one's own and other persons´ emotions) and more personal distress in response to other individuals´ emotional suffering as assessed by self-report.

CONCLUSIONS

The present results suggest that stroke is associated with a broad impact on socioemotional and social problem solving abilities. As difficulties in social problem solving might be associated with increased psychosocial burden they ought to be addressed in stroke rehabilitation.

Web-based mindfulness and skills-based distress reduction for patients with cancer: study protocol of the multicentre, randomised, controlled confirmatory intervention trial Reduct

INTRODUCTION

Many patients with cancer experience severe psychological distress, but as a result of various barriers, few of them receive psycho-oncological support. E-mental health interventions try to overcome some of these barriers and the limitation of healthcare offers, enabling patients with cancer to better cope with psychological distress. In the proposed trial, we aim to assess the efficacy and cost-effectiveness of the manualised e-mental health intervention Make It Training- Mindfulness-Based and Skills-Based Distress Reduction in Oncology. Make It Training is a self-guided and web-based psycho-oncological intervention, which includes elements of cognitive behavioural therapy, mindfulness-based stress reduction and acceptance and commitment therapy. The training supports the patients over a period of 4 months. We expect the Make It Training to be superior to treatment as usual optimised (TAU-O) in terms of reducing distress after completing the intervention (T1, primary endpoint).

METHODS AND ANALYSIS

The study comprises a multicentre, prospective, randomised controlled confirmatory interventional trial with two parallel arms. The proposed trial incorporates four distinct measurement time points: the baseline assessment before randomisation, a post-treatment assessment and 3 and 6 month follow-up assessments. We will include patients who have received a cancer diagnosis in the past 12 months, are in a curative treatment setting, are 18-65 years old, have given informed consent and experience high perceived psychological distress (Hospital Anxiety and Depression Scale ≥13) for at least 1 week. Patients will be randomised into two groups (Make It vs TAU-O). The aim is to allocate 600 patients with cancer and include 556 into the intention to treat analysis. The primary endpoint, distress, will be analysed using a baseline-adjusted ANCOVA for distress measurement once the intervention (T1) has been completed, with study arm as a binary factor, baseline as continuous measurement and study centre as an additional categorical covariate.

ETHICS AND DISSEMINATION

The Ethics Committee of the Medical Faculty Essen has approved the study (21-10076-BO). Results will be published in peer-reviewed journals, conference presentations, the project website, and among self-help organisations.

TRIAL REGISTRATION NUMBER

German Clinical Trial Register (DRKS); DRKS-ID: DRKS00025213.

Metabolic Surgery Supporting Aftercare via Group-Intervention (MeSSAGES): study protocol of a randomised controlled trial

INTRODUCTION

Obesity is a constantly rising and cost-intensive medical issue worldwide. Severe obesity often needs surgery to promote weight loss, but due to the rapid therapeutic success after the surgery, many patients lack the awareness of the need to consistently maintain the postoperative care. However, therapeutic success and psychological well-being can be increased through group interventions and social support of the group members. Therefore, aftercare via group intervention is a promising approach. In this prospective randomised controlled study, the self-efficacy in a social media-based interactive, psychoeducational intervention is to be tested.

METHODS AND ANALYSIS

The intervention group will complete a social media-supported group intervention for 6 weeks with weekly postings of educative contents and the possibility to exchange in groups via anonymous avatars. The control group will receive treatment as usual (TAU) after the obesity surgery as recommended in the German S3-guidelines Obesity Surgery and Metabolic Surgery. We will examine the effectiveness of a social media-supported intervention group, and therefore, the change in self-efficacy expectation. For the primary outcome, we will perform a mixed analysis of variance with time as the within-subject factor (times of measurement T0-T4) and the group assignment as the between-subject factor (intervention +TAU vs TAU group).

ETHICS AND DISSEMINATION

The study was approved by the Medical Association North Rhine (Ärztekammer Nordrhein, 2020031) and the patient enrolment will begin in July 2021.

TRIAL REGISTRATION NUMBER

DRKS00018089.

Determining Acceptance of e-Mental Health Interventions in Digital Psychodiabetology Using a Quantitative Web-Based Survey: Cross-sectional Study

Background

Diabetes is a very common chronic disease that exerts massive physiological and psychological burdens on patients. The digitalization of mental health care has generated effective e-mental health approaches, which offer an indubitable practical value for patient treatment. However, before implementing and optimizing e-mental health tools, their acceptance and underlying barriers and resources should be first determined for developing and establishing effective patient-oriented interventions.

Objective

This study aims to assess the acceptance of e-mental health interventions among patients with diabetes and explore its underlying barriers and resources.

Methods

A cross-sectional study was conducted in Germany from April 9, 2020, to June 15, 2020, through a web-based survey for which patients were recruited via web-based diabetes channels. The eligibility requirements were adult age (18 years or older), a good command of the German language, internet access, and a diagnosis of diabetes. Acceptance was measured using a modified questionnaire, which was based on the well-established Unified Theory of Acceptance and Use of Technology (UTAUT) and assessed health-related internet use, acceptance of e-mental health interventions, and its barriers and resources. Mental health was measured using validated and established instruments, namely the Generalized Anxiety Disorder Scale-7, Patient Health Questionnaire-2, and Distress Thermometer. In addition, sociodemographic and medical data regarding diabetes were collected.

Results

Of the 340 participants who started the survey, 261 (76.8%) completed it and the final sample comprised 258 participants with complete data sets. The acceptance of e-mental health interventions in patients with diabetes was overall moderate (mean 3.02, SD 1.14). Gender and having a mental disorder had a significant influence on acceptance (P<.001). In an extended UTAUT regression model (UTAUT predictors plus sociodemographics and mental health variables), distress (β=.11; P=.03) as well as the UTAUT predictors performance expectancy (β=.50; P<.001), effort expectancy (β=.15; P=.001), and social influence (β=.28; P<.001) significantly predicted acceptance. The comparison between an extended UTAUT regression model (13 predictors) and the UTAUT-only regression model (performance expectancy, effort expectancy, social influence) revealed no significant difference in explained variance (F_10,244=1.567; P=.12).

Conclusions

This study supports the viability of the UTAUT model and its predictors in assessing the acceptance of e-mental health interventions among patients with diabetes. Three UTAUT predictors reached a notable amount of explained variance of 75% in the acceptance, indicating that it is a very useful and efficient method for measuring e-mental health intervention acceptance in patients with diabetes. Owing to the close link between acceptance and use, acceptance-facilitating interventions focusing on these three UTAUT predictors should be fostered to bring forward the highly needed establishment of effective e-mental health interventions in psychodiabetology.

Predicting Acceptance of e-Mental Health Interventions in Patients with Obesity by using an extended Unified Theory of Acceptance Model: Cross-sectional study (Preprint)

Background

The rapid increase in the number of people who are overweight and obese is a worldwide health problem. Obesity is often associated with physiological and mental health burdens. Owing to several barriers to face-to-face psychotherapy, a promising approach is to exploit recent developments and implement innovative e–mental health interventions that offer various benefits to patients with obesity and to the health care system.

Objective

This study aims to assess the acceptance of e–mental health interventions in patients with obesity and explore its influencing predictors. In addition, the well-established Unified Theory of Acceptance and Use of Technology (UTAUT) model is compared with an extended UTAUT model in terms of variance explanation of acceptance.

Methods

A cross-sectional web-based survey study was conducted from July 2020 to January 2021 in Germany. Eligibility requirements were adult age (≥18 years), internet access, good command of the German language, and BMI >30 kg/m² (obesity). A total of 448 patients with obesity (grades I, II, and III) were recruited via specialized social media platforms. The impact of various sociodemographic, medical, and mental health characteristics was assessed. eHealth-related data and acceptance of e–mental health interventions were examined using a modified questionnaire based on the UTAUT.

Results

Overall, the acceptance of e–mental health interventions in patients with obesity was moderate (mean 3.18, SD 1.11). Significant differences in the acceptance of e–mental health interventions among patients with obesity exist, depending on the grade of obesity, age, sex, occupational status, and mental health status. In an extended UTAUT regression model, acceptance was significantly predicted by the depression score (Patient Health Questionnaire-8; β=.07; P=.03), stress owing to constant availability via mobile phone or email (β=.06; P=.02), and confidence in using digital media (β=−0.058; P=.04) and by the UTAUT core predictors performance expectancy (β=.45; P<.001), effort expectancy (β=.22; P<.001), and social influence (β=.27; P<.001). The comparison between an extended UTAUT model (16 predictors) and the restrictive UTAUT model (performance expectancy, effort expectancy, and social influence) revealed a significant difference in explained variance (F_13,431=2.366; P=.005).

Conclusions

The UTAUT model has proven to be a valuable instrument to predict the acceptance of e–mental health interventions in patients with obesity. The extended UTAUT model explained a significantly high percentage of variance in acceptance (in total 73.6%). On the basis of the strong association between acceptance and future use, new interventions should focus on these UTAUT predictors to promote the establishment of effective e–mental health interventions for patients with obesity who experience mental health burdens.

COVID-19-Related Fear and Health-Related Safety Behavior in Oncological Patients

OBJECTIVE

This study aimed to assess cancer patients' psychological burden during the COVID-19 pandemic by investigating distress (distress-thermometer), health status (EQ-5D-3L), general anxiety (GAD-7), COVID-19-related fear and associated behavioral changes and comparing these to matched healthy controls, using propensity score matching (PSM).

METHODS

During the first days of the COVID-19 pandemic in Germany, March 16 to 30, 2020, 150 actually treated cancer patients and 150 matched healthy controls participated in this study. Participants completed an anonymous online survey assessing health status, distress, general anxiety, COVID-19-related fear and behavioral changes (i.e., adherent safety behavior and dysfunctional safety behavior).

RESULTS

Cancer patients showed no elevated level of distress, U = 10,657.5, p = 0.428, general anxiety U = 10,015.5, p = 0.099, or COVID-19-related fear compared to healthy controls, U = 10,948, p = 0.680. Both groups showed elevated COVID-19-related fear. Cancer patients reported more adherent safety behavior, such as washing hands more often or avoiding public places, U = 8,285, p < 0.001, d = 0.468. They also reported more dysfunctional safety behavior such as buying larger quantities of basic food, compared to healthy controls U = 9,599, p = 0.029, d = 0.256. Adherent safety behavior could be significantly explained by cancer diagnosis, increased COVID-19-related fear and subjective level of information about COVID-19, R 2 = 0.215, F(3) = 27.026, p < 0.001.

CONCLUSION

This suggests that cancer patients are more likely to utilize adherent safety behavior. Cancer patients reported comparable levels of distress and anxiety compared to healthy controls. Still, the COVID-19 pandemic is associated with elevated COVID-19-related fear. Therefore, specific interventions are needed to prevent anxiety and improve mental health during the COVID-19 pandemic.

Mental Health Burden of the COVID-19 Outbreak in Germany: Predictors of Mental Health Impairment

INTRODUCTION

COVID-19 is causing an enormous psychological burden for most people. This study aims to assess individual changes in mental health and health status before and after the COVID-19 outbreak, and to explore potential predictors of change.

METHODS

A cross-sectional study in Germany (n = 15 037) were conducted. Demographics, depression and anxiety symptoms (PHQ-2, GAD-2), distress (DT), and health status (EQ-5D-3L) were assessed. Additionally, all instruments used were adapted to measure the participants' mental health and health status before the COVID-19 outbreak. COVID-19-related fear, trust in governmental actions to face COVID-19, and the subjective level of information about COVID-19 were examined.

RESULTS

Overall, the participants showed a significant increase in depression and anxiety symptoms, and distress, while health status deteriorated since the COVID-19 outbreak. Impairment in mental health was predicted by COVID-19-related fear. Pre-existing mental illness predicted an increase in depression symptoms and a deterioration in health status. Trust in governmental actions and the subjective level of information predicted less increase in psychological burden.

CONCLUSIONS

Our data revealed that there have been changes in mental health and health status at an individual level since the outbreak of COVID-19. In order to maintain mental health, the observed predictors should be addressed.

OS2.2 Chemotherapy for spinal gliomas in adults

BACKGROUND

Chemotherapy is a treatment option in patients diagnosed with anaplastic gliomas or glioblastomas of the spinal cord, or with recurrent lower graded WHO spinal gliomas that are no longer amenable to local treatment. The low incidence of spinal cord gliomas, particularly in adults, limits the ability to perform clinical trials. The role of chemotherapy in these tumors has remained unclear.

MATERIAL AND METHODS

We performed a retrospective study of 22 patients diagnosed with spinal gliomas who were treated with chemotherapy at any time during the disease course. Benefit from chemotherapy was estimated by applying Response assessment in neuro-oncology criteria. Data on radiotherapy, as well as the number of neurosurgical interventions were taken into consideration.

RESULTS

Most patients were diagnosed with astrocytoma WHO grade I-IV (N=14), the remaining patients were diagnosed with ependymoma (N=8). Median follow-up from start of chemotherapy was 92 months (95% CI, 72.6–111.4). The O6-methylguanyl-DNA-methyltransferase(MGMT)promoter methylation status was available in tumors of 12 patients: 9 tumors (75%) had an unmethylated MGMTpromoter. More than 50% of the patients had more than one neurosurgical intervention. After prior surgery 10 patients in the first-line setting had chemotherapy combined with radiotherapy, while 3 patients received chemotherapy only. The remaining 9 patients had initially received radiation therapy and chemotherapy was given at time of recurrence. In patients diagnosed with astrocytoma mainly temozolomide (TMZ) was applied (N=10), while one patient received CCNU and three patients had combination chemotherapy. Patients diagnosed with ependymoma had hydroxyurea (N=1), CCNU (N=1), TMZ (N=3) or combination chemotherapy (N=3). In the group of patients who had chemotherapy combined with radiation, response rates were as follows: anaplastic astrocytoma 3 stable diseases (SD), glioblastoma 1 complete response (CR) and 1 SD, and anaplastic ependymoma 1 SD. After chemotherapy in the group of patients previously irradiated, the following response rates were observed: 1 SD in pilocytic astrocytoma, 1 SD in diffuse astrocytoma, 3 SD in myxopapillary ependymoma, and 2 SD and 1 partial response (PR) in anaplastic ependymoma. All other patients experienced progressive disease. There was no indication for a favorable prognostic role ofMGMTpromoter methylation.

CONCLUSION

Spinal cord gliomas represent a heterogeneous group of tumors. Survival outcomes in response to chemotherapy in adult spinal glioma patients vary substantially, but individual patients appear to derive benefit from chemotherapy.

Zusammenhänge zwischen Eigenschaften von 131I-Therapiekapseln und der Radioiodkinetik

Ziel: Es sollte das Auftreten nichtreproduzierbarer Meßwerte bei Radioiodtest und Radioiodkinetik unter 131l-Therapie geklärt werden. Methoden: Der lodgehalt der Kapseln wurde kolonmetrisch und mit der Aktivierungsanalyse bestimmt. Die Messung der radiochemischen Reinheit erfolgte mittels HPLC und Elektrophorese. Das Löseverhalten der Kapseln wurde unter unterschiedlichen Bedingungen überprüft. Ergebnisse: Der lodgehalt der Kapseln schwankte zwischen 0,8 und ca. 100 μg/Kapsel. Die radiochemische Reinheit der Kapseln differierte ebenfalls (75%-99,5%). Hauptverunreinigung war lodat. Das Löseverhalten war ebenfalls unterschiedlich. Schlußfolgerung: Zusätzliches nichtradioaktives lod in den Therapiekapseln könnte eine Ursache verminderter Radioiodaufnahme unter Therapie sein.

Factors affecting the specific activity of [18F]fluoride from a [18O]water target

Aim: Characterisation of the influence of different polymeric tube materials of a water target system, used for the production of 18F activity, on the specific activity of radiotracers. Material, methods: Target water samples taken from different locations of the 18F water target system of a Cyclone® 18/9 cyclotron, equipped with Teflon® (PTFE) or polypropylene (PP) tubes, were analyzed for non-radioactive [19F]fluoride content. [19F]Fluoride content was measured by ion chromatography (IC20, Dinoex) with suppressed conductivity detection. Both the ion chromatographic results and the amount of 18F activity produced were used for the calculation of the specific activity (SA) of [18F]fluoride at the start of the labelling synthesis. To check these results, the SA of the labelled receptor ligand [18F]ZK811460 was also determined by using the different tubing materials. Results: Dose-exposed PTFE tubes of the target dispensing (loading) system were identified to be a major source of [19F]fluoride contamination. Conclusion: By replacing PTFE tubes of the target dispensing system with PP tubes, the content of 19F was reduced considerably resulting in an increase of SA of the radiotracer [18F]ZK811460 by factor of two.

Very stable 188Re-S4 chelates for labelling biomolecules

Aim: The preparation and stability of a new 188Re-S4-complex [S4 = (1-aza-18-crown-6)(O)C-C(SH)-C(SH)- C(O)NH-(CH2)3-NH-(CH2)3-NHC(O)-C(SH)-C(SH)- C(O)(1-aza-18-crown-6] was studied at therapeutic relevant radioactive concentrations. The results were compared with 188Re-MAG3 (MAG3: mercaptoacetyltriglycine) and 188Re-DMSA preparations (DMSA: dimercaptosuccinic acid) performed with the same highly concentrated [188Re]perrhenate solution (12-15 GBq/ml). Methods: The 188Re complexes were prepared by direct reduction of perrhenate (188Re-S4-complex) as well as via the 188Re- EDTA precursor complex (188Re-MAG3, 188Re-DMSA). The preparations were stabilised with 15 mg of ascorbic acid and analysed after 1, 2, and 24 hours by TLC and HPLC. Additionally, in vitro and in vivo stability studies were performed with the purified complexes. Results: After stabilisation with 15 mg of ascorbic acid, all of the complexes were nearly stable under nitrogen for hours, and only 2–8 % of perrhenate was observed after 24 h. In contrast, only the 188Re-S4 complex was completely stable in vitro and in all investigated in vivo samples after separation of ligand excess and reducing agent by HPLC. Conclusion: The bridging amine group or free carboxylic groups of the S4-ligand framework make available reactive positions for coupling biomolecules to the chelate. Thus it appears that the new 188Re-S4 complexes offer the possibility of stable and high specific activity labelling of biomolecules for therapeutic application.

[Direct Drive Simulation - Sound-Simulation of the Vibrant Soundbridge®]

BACKGROUND

The Direct-Drive-Simulation (DDS) tends to simulate the sound quality of hearing with the active middle ear implant Vibrant Soundbridge(®) (VSB). Up to now a scientific evaluation of the validity is missing. Furthermore, the test procedure has not been described yet. Aim of this study was to evaluate the test validity and to describe the test realization in detail.

MATERIAL AND METHODS

10 patients evaluated their sound impression on scales from 1 to 10 concerning sound quality during DDS, postoperative free field testing at least 3 month after the first fitting of the VSB and in the everyday life situation. 3 patients were implanted bilaterally. Together, 36 data sets could be analyzed.

RESULTS

Coupling of the Floating Mass Transducer (FMT), which was placed inside of a silicone probe during DDS was successful in all cases. In 11 out of 13 cases the coupling quality was judged as "good" an only in 2 cases as "medium". None of the patients needed local anesthesia. Comparing the evaluation of the sound impression during DDS preoperatively, and with the implanted VSB in free field testing and in everyday life no significant differences were found.

CONCLUSION

The DDS offers the possibility of a realistic preoperative sound simulation of the "VSB-hearing" in case of sensorineural hearing loss. Thus, the test is supposed to facilitate the patient's decision towards possible treatment options. The specialist gets additional information regarding the indication especially when audiologic indication criteria are critical. The DDS should be a basic part of the preoperative diagnostic prior to VSB-implantation.

An automatic method for accurate volume delineation of heterogeneous tumors in PET

PURPOSE

Accurate volumetric tumor delineation is of increasing importance in radiation treatment planning. Many tumors exhibit only moderate tracer uptake heterogeneity and delineation methods using an adaptive threshold lead to robust results. These methods use a tumor reference value R (e.g., ROI maximum) and the tumor background Bg to compute the volume reproducing threshold. This threshold corresponds to an isocontour which defines the tumor boundary. However, the boundaries of strongly heterogeneous tumors can not be described by an isocontour anymore and therefore conventional threshold methods are not suitable for accurate delineation. The aim of this work is the development and validation of a delineation method for heterogeneous tumors.

METHODS

The new method (voxel-specific threshold method, VTM) can be considered as an extension of an adaptive threshold method (lesion-specific threshold method, LTM), where instead of a lesion-specific threshold for the whole ROI, a voxel-specific threshold is computed by determining for each voxel Bg and R in the close vicinity of the voxel. The absolute threshold for the considered voxel is then given by Tabs=T×(R-Bg)+Bg, where T=0.39 was determined with phantom measurements.

VALIDATION

30 clinical datasets from patients with non-small-cell lung cancer were used to generate 30 realistic anthropomorphic software phantoms of tumors with different heterogeneities and well-known volumes and boundaries. Volume delineation was performed with VTM and LTM and compared with the known lesion volumes and boundaries.

RESULTS

In contrast to LTM, VTM was able to reproduce the true tumor boundaries accurately, independent of the heterogeneity. The deviation of the determined volume from the true volume was (0.8±4.2)% for VTM and (11.0±16.4)% for LTM.

CONCLUSIONS

In anthropomorphic software phantoms, the new method leads to promising results and to a clear improvement of volume delineation in comparison to conventional background-corrected thresholding. In the next step, the suitability for clinical routine will be further investigated.

Evaluation of PET quantification accuracy in vivo. Comparison of measured FDG concentration in the bladder with urine samples

Quantitative positron emission tomography (PET) requires accurate scanner calibration, which is commonly performed using phantoms. It is not clear to what extent this procedure ensures quantitatively correct results in vivo, since certain conditions differ between phantom and patient scans.

AIM

We, therefore, have evaluated the actual quantification accuracy in vivo of PET under clinical routine conditions.

PATIENTS, METHODS

We determined the activity concentration in the bladder in patients undergoing routine [18F]FDG whole body investigations with three different PET scanners (Siemens ECAT EXACT HR+ PET: n = 21; Siemens Biograph 16 PET/CT: n = 16; Philips Gemini-TF PET/CT: n = 19). Urine samples were collected immediately after scan. Activity concentration in the samples was determined in well counters cross-calibrated against the respective scanner. The PET (bladder) to well counter (urine sample) activity concentration ratio was determined.

RESULTS

Activity concentration in the bladder (PET) was systematically lower than in the urine samples (well counter). The patient-averaged PET to well counter ratios for the investigated scanners are (mean ± SEM): 0.881 ± 0.015 (ECAT HR+), 0.898 ± 0.024 (Biograph 16), 0.932 ± 0.024 (Gemini-TF). These values correspond to underestimates by PET of 11.9%, 10.2%, and 6.8%, respectively.

CONCLUSIONS

The investigated PET systems consistently underestimate activity concentration in the bladder. The comparison of urine samples with PET scans of the bladder is a straightforward means for in vivo evaluation of the expectable quantification accuracy. The method might be interesting for multi-center trials, for additional quality assurance in PET and for investigation of PET/MR systems for which clear proof of sufficient quantitative accuracy in vivo is still missing.

Potential of a Cetuximab-based radioimmunotherapy combined with external irradiation manifests in a 3-D cell assay

Targeting epidermal growth factor receptor (EGFR)-overexpressing tumors with radiolabeled anti-EGFR antibodies is a promising strategy for combination with external radiotherapy. In this study, we evaluated the potential of external plus internal irradiation by [(90) Y]Y-CHX-A″-DTPA-C225 (Y-90-C225) in a 3-D environment using FaDu and SAS head and neck squamous cell carcinoma (HNSCC) spheroid models and clinically relevant endpoints such as spheroid control probability (SCP) and spheroid control dose 50% (SCD50 , external irradiation dose inducing 50% loss of spheroid regrowth). Spheroids were cultured using a standardized platform. Therapy response after treatment with C225, CHX-A"-DTPA-C225 (DTPA-C225), [(90) Y]Y-CHX-A"-DTPA (Y-90-DTPA) and Y-90-C225 alone or in combination with X-ray was evaluated by long-term monitoring (60 days) of spheroid integrity and volume growth. Penetration kinetics into spheroids and EGFR binding capacities on spheroid cells were identical for unconjugated C225 and Y-90-C225. Spheroid-associated radioactivity upon exposure to the antibody-free control conjugate Y-90-DTPA was negligible. Determination of the SCD50 demonstrated higher intrinsic radiosensitivity of FaDu as compared with SAS spheroids. Treatment with unconjugated C225 alone did not affect spheroid growth and cell viability. Also, C225 treatment after external irradiation showed no additive effect. However, the combination of external irradiation with Y-90-C225 (1 µg/ml, 24 hr) resulted in a considerable benefit as reflected by a pronounced reduction of the SCD50 from 16 Gy to 9 Gy for SAS spheroids and a complete loss of regrowth for FaDu spheroids due to the pronounced accumulation of internal dose caused by the continuous exposure to cell-bound radionuclide upon Y-90-C225-EGFR interaction.

Automatic volume delineation in oncological PET. Evaluation of a dedicated software tool and comparison with manual delineation in clinical data sets

AIM

Evaluation of a dedicated software tool for automatic delineation of 3D regions of interest in oncological PET.

PATIENTS, METHODS

The applied procedure encompasses segmentation of user-specified subvolumes within the tomographic data set into separate 3D ROIs, automatic background determination, and local adaptive thresholding of the background corrected data. Background correction and adaptive thresholding are combined in an iterative algorithm. Nine experienced observers used this algorithm for automatic delineation of a total of 37 ROIs in 14 patients. Additionally, the observers delineated the same ROIs also manually (using a freely chosen threshold for each ROI) and the results of automatic and manual ROI delineation were compared.

RESULTS

For the investigated 37 ROIs the manual delineation shows a strong interobserver variability of (26.8±6.3)% (range: 15% to 45%) while the corresponding value for automatic delineation is (1.1±1.0)% (range: <0.1% to 3.6%). The fractional deviation of the automatic volumes from the observer-averaged manual ones is (3.7±12.7)%.

CONCLUSION

The evaluated software provides results in very good agreement with observer-averaged manual evaluations, facilitates and accelerates the volumetric evaluation, eliminates the problem of interobserver variability and appears to be a useful tool for volumetric evaluation of oncological PET in clinical routine.

Two or four hour [¹⁸F]FMISO-PET in HNSCC. When is the contrast best?

[¹⁸F]Fluoromisonidazole positron emission tomography (FMISO-PET) is a non invasive imaging technique that can assist detecting intra tumour regions of hypoxia. FMISO-PET evinces comparatively low signal-to-noise-ratio (SNR) and may be acquired dynamically or after different uptake times post injection (p.i.). The aim of this study was to identify, if static images acquired two hours (MISO2) or four hours (MISO4) p.i. reveal higher contrast.

PATIENTS, METHODS

As part of a prospective trial, 23 patients with cancers of the head and neck underwent [¹⁸F]fluorodeoxyglucose (FDG) PET before and during curative radiochemotherapy. Additionally, FMISO-PET studies 2 h and 4 h p.i. were done before treatment and after a mean dose of 11Gy, 23 Gy and 57 Gy during RCT. After coregistration, a dedicated software was used to define the gross tumour volume (GTV) by FDG PET for the primary tumour. This volume was overlaid to the FMISO images and hypoxia within the GTV was determined. The contrast between hypoxia determined by MISO2 and by MISO4 was investigated and analysed with the Wilcoxon-matched-pairs test.

RESULTS

Mean SUVmax in tumours of all examinations was 2.2 (stdev: 0.4, min: 1.3, max: 3.4) after 2 h and 2.4 (stdev: 0.7, min: 1.1, max: 4.4) after 4 h. In the neck musculature the mean SUVmax was 1.5 at both time points and the mean SUVmean decreased from 1.2 after 2 h to 1.1 after 4 h, respectively. These effects resulted in significantly rising contrast ratios from MISO2 to MISO4. The differently defined contrasts revealed significantly higher values for examinations 4 h p.i. (p < 0.002).

CONCLUSION

Data acquisition of [¹⁸F]FMISO should be done 4 h p.i. to gather the optimal contrast, preferably allowing further analysis, e. g. hypoxic sub volume definition for therapy planning.

NOA-08 randomized phase III trial of 1-week-on/1-week-off temozolomide versus involved-field radiotherapy in elderly (older than age 65) patients with newly diagnosed anaplastic astrocytoma or glioblastoma (Methusalem)

LBA2001

Background: The median survival time for elderly patients (pts) with malignant gliomas is in the range of a few months. Radiotherapy (RT) is the standard treatment and superior to best supportive care both with respect to progression-free and overall survival. The benefit derived from surgery and RT is modest, and both treatments are less well tolerated in elderly pts than in the young. The availability of a potentially effective pharmacological agent, temozolomide (TMZ), for malignant glioma, which exhibits a favorable safety profile, necessitated a reconsideration of the widespread therapeutic nihilism with malignant glioma in the elderly.

Methods: The NOA-08 trial of the Neurooncology Working Group (NOA) of the German Cancer Society compared standard postsurgical involved-field RT to a dose of 54-60 Gy, in pts with anaplastic astrocytoma or glioblastoma > 65 ys with a Karnofsky performance score ≥ 60, to TMZ in an one week on/one week off schedule at 100 mg/m2 with dose modification in 25 mg steps in both directions. The primary endpoint was the median survival time (OS) during the follow-up in the 12 months after date of operation. The trial sought to demonstrate the non-inferiority of TMZ compared with RT. Regarding a maximal difference of 25% between both treatment arms in OS as being equivalent, 2 x 206 pts were randomized between May 15, 2005 and Nov 2, 2009 in 22 German and one Suisse sites to provide 80% power to achieve significance at a one-sided level of 0.05. Thirty-nine patients were excluded from the intention-to-treat (ITT) population because no therapy was applied (n=22) or withdrawal of informed consent (n=17).

Results: All histological diagnoses were centrally confirmed. Pts characteristics were balanced between arms in the ITT population (n=373) except for more resections and more anaplastic astrocytomas in the RT arm. The non-inferiority of TMZ was not shown. In contrast, pts in the TMZ arm had an increased risk of death (HR=1.24 [95% CI: 0.94-1.63]) compared to pts in the RT arm. The rate of adverse and serious adverse events was higher in the TMZ arm.

Conclusions: This trial fails to show the non-inferiority of dose-intensified TMZ alone compared with RT alone in the primary treatment of older pts with malignant glioma. Unlike anaplastic glioma in the younger patient population, RT cannot be safely deferred in the treatment of elderly patients with anaplastic astrocytoma or glioblastoma. Whether RT plus TMZ is superior to RT alone, is addressed in the ongoing companion trial conducted by NCIC, EORTC and TROG.

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