14 results on '"Dimitriou, S."'
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2. Preliminary design of a BWB UAV for highway traffic monitoring
- Author
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Dimitriou, S, primary, Kapsalis, S, additional, Dimopoulos, T, additional, Mitridis, D, additional, Pouchias, K, additional, Panagiotou, P, additional, and Yakinthos, K, additional
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- 2022
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3. The influence of cardiorespiratory fitness level on the relationship between work rates at the aerobic threshold (AerT) and the point of maximal fat oxidation (Fat max ) in untrained adults.
- Author
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Pühringer M and Ring-Dimitriou S
- Abstract
Introduction: In this study, we investigated the impact of cardiorespiratory fitness (CRF), quantified as peak oxygen consumption (VO
2peak ), on the relationship between work rates (WR) at the aerobic threshold (AerT) and the point of maximal fat oxidation rate (Fatmax )., Methods: A total of 761 untrained adults aged 41-68 completed a one-minute incremental exercise test on a cycle ergometer, using breath-by-breath gas analysis to determine VO2peak , AerT, and Fatmax . AerT was determined using automatic and visual detection methods, and Fatmax was determined using indirect calorimetry. Participants were categorized into CRF-groups: low (<25th percentile), medium (≥25th percentile and <75th percentile), and high (≥75th percentile)., Results: Fatmax was found at 43 ± 7% WRpeak , 37% ± 6% WRpeak and 35% ± 7% WRpeak in the low, medium, and high CRF-groups, respectively. In contrast, AerT was located at significantly higher relative work rates: 51% ± 8% WRpeak , 47% ± 10% WRpeak , and 47% ± 11% WRpeak in the respective CRF-groups. There was a weak agreement between Fatmax and AerT [intraclass correlation coefficient (ICC) = .19, p < .001], and the ICC decreased from .35 to .12 to .13, while the mean bias ±95% limits of agreement increased from 8% ± 14% WRpeak to 8% ± 19% WRpeak to 12% ± 44% WRpeak from CRF-low to CRF-medium to CRF-high. The mean difference between Fatmax and AerT was significantly different among the CRF subgroups: 8% ± 7% WRpeak vs. 10% ± 10% WRpeak vs. 12% ± 11% WRpeak in low, medium, and high CRF-groups, respectively. Nonetheless, multiple regression analysis revealed only a weak positive correlation between the difference in relative work rates (% WRpeak ) between Fatmax and AerT (dependent variable) and the predictor variables CRF and sex, both identified as significant ( R = .19, p < .001)., Conclusion: Our study confirms substantial differences in exercise intensities between Fatmax and AerT in untrained adults (10% ± 19% WRpeak , ranging from -14% to 53% WRpeak ). Importantly, this difference remains relatively consistent across varying CRF levels, emphasizing the distinct nature of Fatmax and AerT, with CRF playing a limited role in influencing their relationship in our study's untrained adults., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2024 Pühringer and Ring-Dimitriou.)- Published
- 2024
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4. Regional Differences in Self-Reported Health, Physical Activity and Physical Fitness of Urban Senior Citizens in Austria.
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Jungreitmayr S, Venek V, and Ring-Dimitriou S
- Abstract
The aim of this study is to compare data on the health status, self-reported exercise and non-exercise physical activity as well as fitness parameters, such as grip strength, of people in retirement in two cities that are both considered urban centres according to the statistical office of the European Union (EUROSTAT), but differ by geographic location. Self-reported physical activity questionnaires and objective assessments of physical fitness indicators collected by sports scientists were used and examined for differences. A total of 210 people (66.3 years ± 2.3) in Salzburg ( n = 90) and Vienna ( n = 120) was analysed. While no differences were found in self-reported health, there were differences in self-reported exposure to self-reported exercise and non-exercise physical activity, with the Viennese population being more inactive than their more western comparison group. In addition, the objective indicators for muscle strength, balance and flexibility of the lower extremities differed significantly in favour of the more western Austrian population. We recommend assessing the situation of older people in Austria regarding their physical activity and fitness on a regional basis, even if they live in cities of the same category. Future projects should therefore aim to consider specific regional needs during development and incorporate both subjective and objective indicators when monitoring the success of such programs.
- Published
- 2023
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5. FarmDain, a Decision Support System for Dairy Sheep and Goat Production.
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Louta M, Karagiannis P, Papanikolopoulou V, Vouraki S, Tsipis E, Priskas S, Koutouzidou G, Theodoridis A, Dimitriou S, and Arsenos G
- Abstract
Managing a milk zone in the dairy industry is demanding. Data necessary for efficient management are difficult to acquire because they usually must be collected in organized and standardized ways. On the other hand, software practices constantly provide new tools that can go beyond simple record-keeping practices and add value to the data. In this work, FarmDain is a novel web-based application for sheep and goat management. It aims to improve milk production and processing by digitizing the value chain in data acquisition, processing and visualization between dairy production businesses and their milk suppliers. FarmDain uses state-of-the-art software technologies to model the data collection process and provides a straightforward user interface to facilitate data processing and visualization. Using the app in a case study carried out for 12 months in a dairy sheep farm resulted in lower feeding cost per milked ewe by 5.5% when ewes were allocated into high and low milk production groups compared to the scenario of remaining in one single group. Furthermore, based on reports provided by the app, culling and genetic selection decisions were made to improve the overall farm performance. Similar practices were applied in all farms optimizing their productivity, which led to increased profitability for farms and the Dairy Factory.
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- 2023
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6. Associations of clonal hematopoiesis with recurrent vascular events and death in patients with incident ischemic stroke.
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Arends CM, Liman TG, Strzelecka PM, Kufner A, Löwe P, Huo S, Stein CM, Piper SK, Tilgner M, Sperber PS, Dimitriou S, Heuschmann PU, Hablesreiter R, Harms C, Bullinger L, Weber JE, Endres M, and Damm F
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- Humans, Aged, Clonal Hematopoiesis genetics, Prospective Studies, Hematopoiesis genetics, Inflammation genetics, Inflammation complications, Mutation, Ischemic Stroke, Stroke genetics, Stroke complications, Atherosclerosis complications
- Abstract
Clonal hematopoiesis (CH) is common among older people and is associated with an increased risk of atherosclerosis, inflammation, and shorter overall survival. Age and inflammation are major risk factors for ischemic stroke, yet the association of CH with risk of secondary vascular events and death is unknown. We investigated CH in peripheral blood DNA from 581 patients with first-ever ischemic stroke from the Prospective Cohort With Incident Stroke-Berlin study using error-corrected targeted sequencing. The primary composite end point (CEP) consisted of recurrent stroke, myocardial infarction, and all-cause mortality. A total of 348 somatic mutations with a variant allele frequency ≥1% were identified in 236 of 581 patients (41%). CH was associated with large-artery atherosclerosis stroke (P = .01) and white matter lesion (P < .001). CH-positive patients showed increased levels of proinflammatory cytokines, such as interleukin-6 (IL-6), interferon gamma, high-sensitivity C-reactive protein, and vascular cell adhesion molecule 1. CH-positive patients had a higher risk for the primary CEP (hazard ratio [HR], 1.55; 95% confidence interval [CI], 1.04-2.31; P = .03), which was more pronounced in patients with larger clones. CH clone size remained an independent risk factor (HR, 1.30; 95% CI, 1.04-1.62; P = .022) in multivariable Cox regression. Although our data show that, in particular, larger and TET2- or PPM1D-mutated clones are associated with increased risk of recurrent vascular events and death, this risk is partially mitigated by a common germline variant of the IL-6 receptor (IL-6R p.D358A). The CH mutation profile is accompanied by a proinflammatory profile, opening new avenues for preventive precision medicine approaches to resolve the self-perpetuating cycle of inflammation and clonal expansion., (© 2023 by The American Society of Hematology.)
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- 2023
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7. Sequencing patterns of ventilatory indices in less trained adults.
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Pühringer M, Ring-Dimitriou S, Iglseder B, Frey V, Trinka E, and Paulweber B
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Submaximal ventilatory indices, i.e., point of optimal ventilatory efficiency (POE) and anaerobic threshold (AT), are valuable indicators to assess the metabolic and ventilatory response during cardiopulmonary exercise testing (CPET). The order in which the ventilatory indices occur (ventilatory indices sequencing pattern, VISP), may yield additional information for the interpretation of CPET results and for exercise intensity prescription. Therefore, we determined whether different VISP groups concerning POE and AT exist. Additionally, we analysed fat metabolism via the exercise intensity eliciting the highest fat oxidation rate (Fat
max ) as a possible explanation for differences between VISP groups. 761 less trained adults (41-68 years) completed an incremental exercise test on a cycle ergometer until volitional exhaustion. The ventilatory indices were determined using automatic and visual detection methods, and Fatmax was determined using indirect calorimetry. Our study identified two VISP groups with a lower work rate at POE compared to AT in VISPPOE < AT but not in group VISPPOE = AT . Therefore, training prescription based on POE rather than AT would result in different exercise intensity recommendations in 66% of the study participants and consequently in unintended physiological adaptions. VISPPOE < AT participants were not different to VISPPOE = AT participants concerning VO2peak and Fatmax . However, participants exhibiting a difference in work rate (VISPPOE < AT ) were characterized by a higher aerobic capacity at submaximal work rate compared to VISPPOE = AT . Thus, analysing VISP may help to gain new insights into the complex ventilatory and metabolic response to exercise. But a methodological framework still must be established., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2023 Pühringer, Ring-Dimitriou, Iglseder, Frey, Trinka and Paulweber.)- Published
- 2023
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8. Comparison of iCOR and Rayleigh atmospheric correction methods on Sentinel-3 OLCI images for a shallow eutrophic reservoir.
- Author
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Katsoulis-Dimitriou S, Lefkaditis M, Barmpagiannakos S, Kormas KA, and Kyparissis A
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- Harmful Algal Bloom, Time Factors, Water Quality, Chlorophyll
- Abstract
Remote sensing of inland waters is challenging, but also important, due to the need to monitor the ever-increasing harmful algal blooms (HABs), which have serious effects on water quality. The Ocean and Land Color Instrument (OLCI) of the Sentinel-3 satellites program is capable of providing images for the monitoring of such waters. Atmospheric correction is a necessary process in order to retrieve the desired surface-leaving radiance signal and several atmospheric correction methods have been developed through the years. However, many of these correction methods require programming language skills, or function as commercial software plugins, limiting their possibility of use by end users. Accordingly, in this study, the free SNAP software provided by the European Space Agency (ESA) was used to evaluate the possible differences between a partial atmospheric correction method accounting for Rayleigh scattering and a full atmospheric correction method (iCOR), applied on Sentinel-3 OLCI images of a shallow, highly eutrophic water reservoir. For the complete evaluation of the two methods, in addition to the comparison of the band reflectance values, chlorophyll (CHL) and cyanobacteria (CI) indices were also calculated and their values were intercompared. The results showed, that although the absolute values between the two correction methods did not coincide, there was a very good correlation between the two methods for both bands' reflectance ( r > 0.73) and the CHL and CI indices values ( r > 0.95). Therefore, since iCOR correction image processing time is 25 times longer than Rayleigh correction, it is proposed that the Rayleigh partial correction method may be alternatively used for seasonal water monitoring, especially in cases of long time-series, enhancing time and resources use efficiency. Further comparisons of the two methods in other inland water bodies and evaluation with in situ chlorophyll and cyanobacteria measurements will enhance the applicability of the methodology., Competing Interests: Konstantinos A. Kormas is an Academic Editor for PeerJ., (©2022 Katsoulis-Dimitriou et al.)
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- 2022
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9. Influence of 2 Digital Exercise Modules of a Multimodular System on Balance and Leg Strength Under Consideration of Use Adherence: Prospective Cohort Study.
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Venek V, Kranzinger C, Jungreitmayr S, Ring-Dimitriou S, Schwameder H, and Stöggl T
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Background: To empower healthy aging, digital solutions embed multiple modules for physical activity, cognitive health promotion, and social engagement. Integrating new empowering technologies such as digital exercise monitoring requires assessment measures and analysis procedures, considering variable compliance of users with different modules., Objective: This study aims to assess the influence of a tablet-based and a feedback system-based exercise module on balance and leg strength by considering use adherence instead of the use of the entire multimodular system., Methods: In the prospective cohort study within the fit4AAL project, 83 users (n=67, 81% women; n=16, 19% men; mean age 66.2, SD 2.3 years) used the 2 digital exercise modules of a multimodular physical activity promotion system for >18 weeks. A data-driven clustering method based on the average use frequency of the exercise modules determined the number of user types that met the World Health Organization-recommended training frequency of at least twice per week. On the basis of this use adherence, statistical analysis was performed with features of functional performance tests (unipedal stance, 30-second chair rise, Y-balance, and hurdle step tests). The tests were conducted 6 months before the intervention, immediately before the intervention, and after the intervention, comparing the baseline phase with the 3 feedback use groups of the study (using only the tablet, the tablet and the feedback system, or only the feedback system)., Results: Of the 83 users, 43 (52%) met the World Health Organization-recommended frequency of muscle-strengthening activities. Overall, the feedback use groups achieved, on average, more chair rises in 30 seconds than the baseline group (P=.01; moderate effect size of 0.07). Of the 43 users, 26 (60%) additionally used the feedback system-based exercise module. They improved in balance compared with the users using either the tablet or the feedback system (P=.02). In addition, they improved their leg strength within the group (P=.04) and compared with the baseline (P=.01)., Conclusions: The additional use of a feedback system showed a tendency to positively maintain and influence the already exceptionally high functional performance of older adults. Considering use adherence in future multimodular system studies is crucial to assess the influence of single and combined use of exercise modules on functional performance., (©Verena Venek, Christina Kranzinger, Sonja Jungreitmayr, Susanne Ring-Dimitriou, Hermann Schwameder, Thomas Stöggl. Originally published in JMIR Formative Research (https://formative.jmir.org), 19.09.2022.)
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- 2022
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10. Data-Driven User-Type Clustering of a Physical Activity Promotion App: Usage Data Analysis Study.
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Kranzinger C, Venek V, Rieser H, Jungreitmayr S, and Ring-Dimitriou S
- Abstract
Background: Physical inactivity remains a leading risk factor for mortality worldwide. Owing to increasing sedentary behavior (activities in a reclining, seated, or lying position with low-energy expenditures), vehicle-based transport, and insufficient physical workload, the prevalence of physical activity decreases significantly with age. To promote sufficient levels of participation in physical activities, the research prototype Fit-mit-ILSE was developed with the goal of making adults aged ≥55 years physically fit and fit for the use of assistive technologies. The system combines active and assisted living technologies and smart services in the ILSE app., Objective: The clustering of health and fitness app user types, especially in the context of active and assisted living projects, has been mainly defined by experts through 1D cluster thresholds based on app usage frequency. We aimed to investigate and present data-driven methods for clustering app user types and to identify usage patterns based on the ILSE app function Fit at home., Methods: During the 2 phases of the field trials, ILSE app log data were collected from 165 participants. Using this data set, 2 data-driven approaches were applied for clustering to group app users who were similar to each other. First, the common approach of user-type clustering based on expert-defined thresholds was replaced by a data-driven derivation of the cluster thresholds using the Jenks natural breaks algorithm. Second, a multidimensional clustering approach using the Partitioning Around Medoids algorithm was explored to consider the detailed app usage pattern data., Results: Applying the Jenks clustering algorithm to the mean usage per day and clustering the users into 4 groups showed that most of the users (63/165, 38.2%) used the Fit at home function between once a week and every second day. More men were in the low usage group than women. In addition, the younger users were more often identified as moderate or high users than the older users, who were mainly classified as low users; moreover, the regional differences between Vienna and Salzburg were identified. In addition, the multidimensional approach identified 4 different user groups that differed mainly in terms of time of use, gender, and region. Overall, the younger women living in Salzburg were the users with highest average app usage., Conclusions: The application of different clustering approaches showed that data-driven calculations of user groups can complement expert-based definitions, provide objective thresholds for the analysis of app usage data, and identify groups that can be targeted individually based on their specific group characteristics., (©Christina Kranzinger, Verena Venek, Harald Rieser, Sonja Jungreitmayr, Susanne Ring-Dimitriou. Originally published in JMIR Formative Research (https://formative.jmir.org), 01.08.2022.)
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- 2022
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11. Lactate Thresholds and the Simulation of Human Energy Metabolism: Contributions by the Cologne Sports Medicine Group in the 1970s and 1980s.
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Wackerhage H, Gehlert S, Schulz H, Weber S, Ring-Dimitriou S, and Heine O
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Today, researchers, practitioners, and physicians measure the concentration of lactate during a graded exercise test to determine thresholds related to the maximal lactate steady state (maxLass) as a sensitive measure of endurance capacity. In the 1970s and 1980s, a group of Cologne-based researchers around Wildor Hollmann, Alois Mader, and Hermann Heck developed the methodology for systematic lactate testing and introduced a 4 mmol
. L-1 lactate threshold. Later, they also developed the concept of the maxLass, and Mader designed a sophisticated mathematical model of human energy metabolism during exercise. Mader`s model simulates metabolic responses to exercise based on individual variables such as maximum oxygen uptake ( V ˙ O2max ) and the maximal rate of lactate formation (νLa.max ). Mader's model predicts that the νLa.max reduces the power at the anaerobic threshold and endurance performance but that a high νLa.max is required for events with high power outputs in elite athletes. Mader's model also assumed before the millennium that the rate of fat oxidation is explained by the difference between glycolytic pyruvate synthesis and the actual rate of pyruvate oxidation which is consistent with current opinion. Mader's model also simulated the V ˙ O2max slow component in the mid-1980s. Unfortunately, several landmark studies by the Cologne group were only published in German, and as a result, contributions by the Cologne group are under-appreciated in the English-speaking world. This narrative review aims to introduce key contributions of the Cologne group to human metabolism research especially for readers who do not speak German., Competing Interests: Author SW is employed by INSCYD GmbH. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Wackerhage, Gehlert, Schulz, Weber, Ring-Dimitriou and Heine.)- Published
- 2022
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12. Clonal hematopoiesis is associated with improved survival in patients with metastatic colorectal cancer from the FIRE-3 trial.
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Arends CM, Dimitriou S, Stahler A, Hablesreiter R, Strzelecka PM, Stein CM, Tilgner M, Saiki R, Ogawa S, Bullinger L, Modest DP, Stintzing S, Heinemann V, and Damm F
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- Bevacizumab, Hematopoiesis, Humans, Clonal Hematopoiesis, Colorectal Neoplasms genetics, Colorectal Neoplasms pathology
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- 2022
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13. Effects of an App-Based Physical Exercise Program on Selected Parameters of Physical Fitness of Females in Retirement: A Randomized Controlled Trial.
- Author
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Jungreitmayr S, Kranzinger C, Venek V, and Ring-Dimitriou S
- Abstract
Modern technologies enable new options in the delivery of physical exercise programs. Specially designed app-based programs can be used to help older people in particular to integrate physical exercise into their daily lives. This study examines the influence of an app-based physical exercise program on selected parameters of physical fitness, such as muscular strength, balance, and flexibility. The women ( n = 110) were on average 65.3 (± 1.5) years old and, compared to age-specific norm values, healthy. The 14-week intervention consisted of an app-based, unsupervised physical exercise program, in which the exercise frequency and duration of sessions were self-selected. The physical exercise program consisted of simple, functional exercises such as arm circles, squats, lateral raises. The participants were provided with an elastic resistance band and an exercise ball allowing them to increase exercise intensity if needed. Participants were randomly assigned to intervention group (IG) and control group (CG). 71% of the IG used the physical exercise program at least 1.2 times per week, whereas 25% of the IG showed usage rates above four times per week. Significant effects were found in the domains of muscular strength and flexibility. While IG could maintain their performance in isometric muscular strength tests and increased their flexibility, CG faced a decrease in those parameters. Thus, this app-based physical exercise program had positively influenced muscular strength and flexibility in women over 60 years of age., Competing Interests: CK and VV were employed by company Salzburg Research Forschungsgesellschaft mbH. SJ is the owner of MyBodyCoach. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Jungreitmayr, Kranzinger, Venek and Ring-Dimitriou.)
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- 2022
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14. Biomolecular and Genetic Prognostic Factors That Can Facilitate Fertility-Sparing Treatment (FST) Decision Making in Early Stage Endometrial Cancer (ES-EC): A Systematic Review.
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Tanos P, Dimitriou S, Gullo G, and Tanos V
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- Decision Making, Endometrium, Female, Humans, Pregnancy, Prognosis, Endometrial Neoplasms drug therapy, Endometrial Neoplasms therapy, Fertility Preservation
- Abstract
Endometrial cancer occurs in up to 29% of women before 40 years of age. Seventy percent of these patients are nulliparous at the time. Decision making regarding fertility preservation in early stage endometrial cancer (ES-EC) is, therefore, a big challenge since the decision between the risk of cancer progression and a chance to parenthood needs to be made. Sixty-two percent of women with complete remission of ES-EC after fertility-sparing treatment (FST) report to have a pregnancy wish which, if not for FST, they would not be able to fulfil. The aim of this review was to identify and summarise the currently established biomolecular and genetic prognostic factors that can facilitate decision making for FST in ES-EC. A comprehensive search strategy was carried out across four databases; Cochrane, Embase, MEDLINE, and PubMed; they were searched between March 1946 and 22nd December 2022. Thirty-four studies were included in this study which was conducted in line with the PRISMA criteria checklist. The final 34 articles encompassed 9165 patients. The studies were assessed using the Critical Appraisal Skills Program (CASP). PTEN and POLE alterations we found to be good prognostic factors of ES-EC, favouring FST. MSI, CTNNB1 , and K-RAS alterations were found to be fair prognostic factors of ES-EC, favouring FST but carrying a risk of recurrence. PIK3CA , HER2 , ARID1A , P53 , L1CAM , and FGFR2 were found to be poor prognostic factors of ES-EC and therefore do not favour FST. Clinical trials with bigger cohorts are needed to further validate the fair genetic prognostic factors. Using the aforementioned good and poor genetic prognostic factors, we can make more confident decisions on FST in ES-EC.
- Published
- 2022
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