Splenic vein tumor thrombosis is a major prognostic factor in distal pancreatic adenocarcinoma

BACKGROUND

The prognostic value of splenic vessel involvement in distal pancreatic adenocarcinoma remains controversial. The aim of the study was to assess its prognostic relevance in a large multicenter cohort.

METHODS

Patients who underwent pancreatosplenectomy for distal pancreatic adenocarcinoma were identified from 5 pancreatic surgical centers. A pathology review of the surgical specimens was performed to assess splenic vessel involvement, defined as invasion of the vessel's adventitia or deeper, and confirm the presence of splenic vein tumor thrombosis. Prognostic factors associated with overall and relapse-free survival were evaluated.

RESULTS

149 patients underwent upfront surgery. Splenic vascular involvement was observed in 69 of them (46.3%). A parietal infiltration of the splenic artery or splenic vein was observed in 26 (17.5%) and 49 patients (32.8%), respectively. A pathologic tumor thrombosis of the splenic vein was identified in 22 patients (14.8%) and associated with larger tumors (>20 mm) (P = .023), more perineural (P = .017), and lymphovascular (P = .002) invasion, and more positive lymph node (P = .001). After a median follow-up of 50.8 months (95% confidence interval: 44.3-57.3), the cumulative 5-year overall and relapse-free survival were 46.2% and 33%, respectively. In multivariate analysis, in addition to lymph node metastasis (hazard ratio = 1.8; 95% confidence interval [1.1-3.1]; P = .023) and perineural invasion (hazard ratio = 3.5; 95% confidence interval [1.3-9.7]; P = .016), presence of splenic vein tumor thrombosis was the only splenic vascular involvement that affected independently the overall survival (HR = 2.3; 95% confidence interval [ 1.3-4.3]; P = .006).

CONCLUSION

In resectable distal pancreatic adenocarcinoma, a pathologic tumor thrombosis of the splenic vein is an independent prognostic factor of overall survival. To define the perioperative oncological strategy, a preoperative evaluation of splenic vessel involvement and thrombosis is needed.

No correlation between MASLD and poor outcome of Atezolizumab-Bevacizumab therapy in patients with advanced HCC

INTRODUCTION

It has been suggested that in patients with hepatocellular carcinoma (HCC) of metabolic aetiology, the efficacy of immunotherapy may be reduced. The aim was to investigate the impact of metabolic-associated steatotic liver disease (MASLD) and metabolic risk factors (MRF) on the outcomes of Atezolizumab-Bevacizumab (AtezoBev).

METHODS

We collected data from 295 AtezoBev-treated patients, starting in 2020. MASLD was defined by the current/past presence of MRF, namely BMI ≥ 30 kg/m2, type 2 diabetes, arterial hypertension or dyslipidaemia and no other cause of liver disease (daily alcohol ≤30 g in males and ≤20 g in females). The influence of baseline characteristics on progression (PFS) and overall survival (OS) was assessed by uni/multivariate analysis using the Cox model.

RESULTS

Risk factors for cirrhosis were viral infection in 47%, excessive alcohol consumption in 45% and MASLD in 13%. In the whole cohort, 27% had 1 MRF, 23% had 2 MRF, 15% had 3 MRF and 6% had 4 MRF. Median PFS and OS were 6.5 and 15.6 months, respectively, and similar in patients with or without MASLD in Log rank analysis. The number of MRF or MALSD was not associated with PFS or OS in the univariate analysis. Factors associated with PFS in multivariate analysis included ALBI grade 3 (HR = 1.60, p = .03), AFP (HR = 1.01, p = .01) and metastasis (HR = 1.77, p < .001). During follow-up, 10% of patients experienced immune-related adverse events, with age and female gender, but not MRF or MASLD, as independent predictors.

CONCLUSION

Our study suggests that the presence of MASLD or the number of MRF did not lead to worse outcomes in advanced HCC patients treated with AtezoBev.

Active surveillance for low-grade appendiceal mucinous neoplasm (LAMN)

Objectives

Due to the scarcity of low-grade appendiceal mucinous neoplasm (LAMN), there is an absence of systematized guidelines concerning its management, especially after incidental finding on an appendiceal specimen. In this study, we evaluate the active surveillance (AS) strategy adopted for a series of patients diagnosed with LAMN on resection specimens who were considered to have a low risk of pseudomyxoma progression.

Methods

Thirty patients were included between April 2014 and July 2021, with a female majority and a median follow-up period of 3.1 years. The inclusion criteria were as follows: LAMN diagnosis on appendiceal specimens, confirmed in an expert center, limited extra-appendiceal mucin resected and localized around the appendix, normal biology (CEA, CA199, CA125) and normal abdominopelvic MRI. AS included physical exam (trocar scar), biology and MRI, 6 months postoperatively, then yearly for 10 years.

Results

As an initial surgery, 77 % had an appendectomy as their initial intervention, 17 % had a cecectomy, and 6 % had a right colectomy. After follow-up, 87 % of patients showed no sign of disease progression by MRI, while 13 % progressed to PMP. MRI performed in the first postoperative year predicted the disease prognosis in 97 % of patients.

Conclusions

The AS strategy, based on MRI, is a valid option after incidental LAMN diagnosis.

Appendiceal adenocarcinoma, diagnosed after acute perforated appendicitis: Potential contribution of HIPEC

INTRODUCTION

Treatment of peritoneal metastasis from appendicular adenocarcinoma consists of cyto-reductive surgery (CRS) and Hyperthermic IntraPEritoneal Chemotherapy (HIPEC). In case of acute appendicular syndrome (AAS) the tumor is likely to be perforated. In that case, there is no treatment recommendation. We propose CRS and HIPEC.

MATERIALS AND METHOD

We listed 21 consecutive patients who were addressed for discovery of appendiceal adenocarcinoma. The emergency surgery was performed in a primary-care hospital. We evaluated the therapeutic algorithms, per operative decision, survival and recurrent rate.

RESULTS

Among the 21 patients, 4 patients were diagnosed as synchronous appendicular peritoneal metastasis, and underwent CRS and HIPEC. The other 17 patients with diagnosis of adenocarcinoma on anatomopathological samples, without peritoneal metastasis during appendectomy, were addressed. Between them 2 patients were denied CRS. Among the 15 operated patients, 8 patients had no peritoneal metastasis discovery during surgery, and therefore underwent prophylactic CRS and HIPEC. Peritoneal metastasis were discovered for the other 7 patients, who also underwent CRS and HIPEC. For the prophylactic group, the recurrence rate is 12,5 %, overall survival (OS) is 100 %. The rate of grade III-IV surgical complications after CRS and HIPEC was 36 % among the 19 patients who underwent surgery.

CONCLUSION

In case of appendectomy in emergency situations for perforated adenocarcinoma, half of the patients may have peritoneal metastasis. In case of non-identified peritoneal metastasis during CRS, performing a prophylactic HIPEC seems to be associated with an encouraging rate of peritoneal disease free situation at 5 years.

Deep learning for automatic bowel-obstruction identification on abdominal CT

RATIONALE AND OBJECTIVES

Automated evaluation of abdominal computed tomography (CT) scans should help radiologists manage their massive workloads, thereby leading to earlier diagnoses and better patient outcomes. Our objective was to develop a machine-learning model capable of reliably identifying suspected bowel obstruction (BO) on abdominal CT.

MATERIALS AND METHODS

The internal dataset comprised 1345 abdominal CTs obtained in 2015-2022 from 1273 patients with suspected BO; among them, 670 were annotated as BO yes/no by an experienced abdominal radiologist. The external dataset consisted of 88 radiologist-annotated CTs. We developed a full preprocessing pipeline for abdominal CT comprising a model to locate the abdominal-pelvic region and another model to crop the 3D scan around the body. We built, trained, and tested several neural-network architectures for the binary classification (BO, yes/no) of each CT. F1 and balanced accuracy scores were computed to assess model performance.

RESULTS

The mixed convolutional network pretrained on a Kinetics 400 dataset achieved the best results: with the internal dataset, the F1 score was 0.92, balanced accuracy 0.86, and sensitivity 0.93; with the external dataset, the corresponding values were 0.89, 0.89, and 0.89. When calibrated on sensitivity, this model produced 1.00 sensitivity, 0.84 specificity, and an F1 score of 0.88 with the internal dataset; corresponding values were 0.98, 0.76, and 0.87 with the external dataset.

CONCLUSION

The 3D mixed convolutional neural network developed here shows great potential for the automated binary classification (BO yes/no) of abdominal CT scans from patients with suspected BO.

CLINICAL RELEVANCE STATEMENT

The 3D mixed CNN automates bowel obstruction classification, potentially automating patient selection and CT prioritization, leading to an enhanced radiologist workflow.

KEY POINTS

• Bowel obstruction's rising incidence strains radiologists. AI can aid urgent CT readings. • Employed 1345 CT scans, neural networks for bowel obstruction detection, achieving high accuracy and sensitivity on external testing. • 3D mixed CNN automates CT reading prioritization effectively and speeds up bowel obstruction diagnosis.

Association of LI-RADS and Histopathologic Features with Survival in Patients with Solitary Resected Hepatocellular Carcinoma

Background Both Liver Imaging Reporting and Data System (LI-RADS) and histopathologic features provide prognostic information in patients with hepatocellular carcinoma (HCC), but whether LI-RADS is independently associated with survival is uncertain. Purpose To assess the association of LI-RADS categories and features with survival outcomes in patients with solitary resected HCC. Materials and Methods This retrospective study included patients with solitary resected HCC from three institutions examined with preoperative contrast-enhanced CT and/or MRI between January 2008 and December 2019. Three independent readers evaluated the LI-RADS version 2018 categories and features. Histopathologic features including World Health Organization tumor grade, microvascular and macrovascular invasion, satellite nodules, and tumor capsule were recorded. Overall survival and disease-free survival were assessed with Cox regression models. Marginal effects of nontargetoid features on survival were estimated using propensity score matching. Results A total of 360 patients (median age, 64 years [IQR, 56-70 years]; 280 male patients) were included. At CT and MRI, the LI-RADS LR-M category was associated with increased risk of recurrence (CT: hazard ratio [HR] = 1.83 [95% CI: 1.26, 2.66], P = .001; MRI: HR = 2.22 [95% CI: 1.56, 3.16], P < .001) and death (CT: HR = 2.47 [95% CI: 1.72, 3.55], P < .001; MRI: HR = 1.80 [95% CI: 1.32, 2.46], P < .001) independently of histopathologic features. The presence of at least one nontargetoid feature was associated with an increased risk of recurrence (CT: HR = 1.80 [95% CI: 1.36, 2.38], P < .001; MRI: HR = 1.93 [95% CI: 1.81, 2.06], P < .001) and death (CT: HR = 1.51 [95% CI: 1.10, 2.07], P < .010) independently of histopathologic features. In matched samples, recurrence was associated with the presence of at least one nontargetoid feature at CT (HR = 2.06 [95% CI: 1.15, 3.66]; P = .02) or MRI (HR = 1.79 [95% CI: 1.01, 3.20]; P = .048). Conclusion In patients with solitary resected HCC, LR-M category and nontargetoid features were negatively associated with survival independently of histopathologic characteristics. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Kartalis and Grigoriadis in this issue.

Enhanced therapeutic outcomes with atezolizumab-bevacizumab and SIRT combination compared to SIRT alone in unresectable HCC: A promising approach for improved survival

BACKGROUND

Integrating immunotherapy with locoregional therapies marks a significant milestone in the realm of hepatocellular carcinoma (HCC) treatment . This study aimed to assess the impact of addition of Atezolizumab-Bevacizumab (AtezoBev) on the outcome patients treated with SIRT.

METHODS

We conducted a study that included all Child-Pugh A HCC treated with SIRT since 2017. We examined the effects of the addition of 3 infusions of AtezoBev before the SIRT procedure and after SIRT on patients outcome (AtezoBev-SIRT group). Time-to-event data were analyzed using Kaplan-Meier with the log-rank test.

RESULTS

Thirty five HCC patients treated with SIRT were included, of whom 23 % also received AtezoBev infusions. The two groups were similar in terms of liver function and HCC parameters. The median OS was not reached for patients who received AtezoBev in combination with SIRT and 14 months for patients only treated by SIRT. The median PFS was higher in the group treated by SIRT and AtezoBev vs SIRT alone (11.3 months vs 5.8 months). In the global cohort, 8 patients presented a downstaging (23 %), 4 underwent liver surgery (1 in the AtezoBev-SIRT group) and 4 liver transplantation (1 in the AtezoBev-SIRT group) CONCLUSIONS: The administration of AtezoBev, both before and after SIRT, is associated with enhanced OS and PFS outcomes compared to SIRT alone for unresectable HCC.

Impact of radiological response and pattern of progression in patients with HCC treated by atezolizumab-bevacizumab

BACKGROUND AND AIMS

We aim to assess the role of radiological response to atezolizumab-bevacizumab in patients with HCC to predict overall survival.

APPROACH AND RESULTS

We retrospectively included patients with HCC treated by atezolizumab-bevacizumab in 2 tertiary centers. A retrospective blinded analysis was performed by 2 radiologists to assess Response Evaluation Criteria in Solid Tumor (RECIST 1.1) and modified RECIST (mRECIST) criteria at 12 weeks. Imaging response and treatment decisions in the multidisciplinary tumor board at 12 weeks were registered. Among 125 patients, 9.6% and 20.8% had a response, 39.2% and 35.2% had stable disease, and 51.2% and 44% had progression, according to RECIST 1.1 and mRECIST, respectively, with a substantial interobserver agreement (k coefficient=0.79). Metastasis was independently associated with a higher risk of progression. Patients classified as responders did not reach median survival, which was 16.2 and 15.9 months for patients classified as stable and 9.1 and 9.0 months for patients classified as progressors, in RECIST 1.1 and mRECIST criteria, respectively. We observed a wide variability in the identification of progression in the multidisciplinary tumor board in clinical practice compared with the blind evaluation by radiologists mainly due to discrepancy in the evaluation of the increase in size of intrahepatic lesions. The appearance of new extrahepatic lesions or vascular invasion lesions was associated with a worse overall survival ( p =0.032).

CONCLUSIONS

RECIST 1.1 and mRECIST criteria predict overall survival with more responders identified by mRECIST and the appearance of new extrahepatic lesion or vascular invasion was associated with a poor prognosis. A noticeable discrepancy was observed between patients classified as progressors at reviewing and the decision reached during the multidisciplinary tumor board.

Gaussian Process-based prediction of memory performance and biomarker status in ageing and Alzheimer's disease-A systematic model evaluation

Neuroimaging markers based on Magnetic Resonance Imaging (MRI) combined with various other measures (such as genetic covariates, biomarkers, vascular risk factors, neuropsychological tests etc.) might provide useful predictions of clinical outcomes during the progression towards Alzheimer's disease (AD). The use of multiple features in predictive frameworks for clinical outcomes has become increasingly prevalent in AD research. However, many studies do not focus on systematically and accurately evaluating combinations of multiple input features. Hence, the aim of the present work is to explore and assess optimal combinations of various features for MR-based prediction of (1) cognitive status and (2) biomarker positivity with a multi-kernel learning Gaussian process framework. The explored features and parameters included (A) combinations of brain tissues, modulation, smoothing, and image resolution; (B) incorporating demographics & clinical covariates; (C) the impact of the size of the training data set; (D) the influence of dimensionality reduction and the choice of kernel types. The approach was tested in a large German cohort including 959 subjects from the multicentric longitudinal study of cognitive impairment and dementia (DELCODE). Our evaluation suggests the best prediction of memory performance was obtained for a combination of neuroimaging markers, demographics, genetic information (ApoE4) and CSF biomarkers explaining 57% of outcome variance in out-of-sample predictions. The highest performance for Aβ42/40 status classification was achieved for a combination of demographics, ApoE4, and a memory score while usage of structural MRI further improved the classification of individual patient's pTau status.

Portal-hypertension features are associated with ascites occurrence and survival in patients with hepatocellular carcinoma treated by external radiotherapy

BACKGROUND AND AIMS

We studied the impact of Portal hypertension (PHT) on ascites occurrence and on radiotherapy outcome in cirrhotic patients with hepatocellular carcinoma (HCC).

METHOD

All cirrhotic patients that received radiotherapy for HCC between 2012 and 2022 were included. Portal hypertension-Score was built using univariate analysis with the presence of esophageal varices (EV), platelet count, history of acute variceal bleeding (AVB) and spleen size. Time-to-events data were estimated using Kaplan-Meier method with log-rank and Cox-models.

RESULTS

60 patients were included (female 27%, age 67 years-old, Child-Pugh A 82%, alcoholic/non-alcoholic steatohepatitis/hepatitis C virus 55/40/32%). 38% and 15% presented history of ascites and AVB respectively, 25% had large EV, 53.5% presented PHT score ≥ 5. 92% were BCLC-0/A, median tumor size was 30 mm. At 6 months, ascites incidence was 19% and precluded access to further HCC treatment for all patients with HCC recurrence. All PHT parameters included in the score and PHT score ≥ 5 (hazard ratio (HR) = 14.07, p = 0.01) were associated with ascites occurrence. Transplantation free survival and recurrence free survival at 1 year were 56% and 47% respectively. Albi grade 3 (HR = 3.01; p = 0.04) was independently associated with Transplantation free survival.

CONCLUSION

Radiotherapy should be cautiously performed in patients with PHT score ≥ 5 because of ascites occurrence risk precluding access to further HCC treatments.

Liver Investigation: Testing Marker Utility in Steatohepatitis (LITMUS): Assessment & validation of imaging modality performance across the NAFLD spectrum in a prospectively recruited cohort study (the LITMUS imaging study): Study protocol

Non-alcoholic fatty liver disease (NAFLD) is the liver manifestation of the metabolic syndrome with global prevalence reaching epidemic levels. Despite the high disease burden in the population only a small proportion of those with NAFLD will develop progressive liver disease, for which there is currently no approved pharmacotherapy. Identifying those who are at risk of progressive NAFLD currently requires a liver biopsy which is problematic. Firstly, liver biopsy is invasive and therefore not appropriate for use in a condition like NAFLD that affects a large proportion of the population. Secondly, biopsy is limited by sampling and observer dependent variability which can lead to misclassification of disease severity. Non-invasive biomarkers are therefore needed to replace liver biopsy in the assessment of NAFLD. Our study addresses this unmet need. The LITMUS Imaging Study is a prospectively recruited multi-centre cohort study evaluating magnetic resonance imaging and elastography, and ultrasound elastography against liver histology as the reference standard. Imaging biomarkers and biopsy are acquired within a 100-day window. The study employs standardised processes for imaging data collection and analysis as well as a real time central monitoring and quality control process for all the data submitted for analysis. It is anticipated that the high-quality data generated from this study will underpin changes in clinical practice for the benefit of people with NAFLD. Study Registration: clinicaltrials.gov: NCT05479721.

Albumin infusion reduces ascite occurrence in Child-Pugh B patients treated by Atezolizumab-Bevacizumab for advanced HCC

BACKGROUND

Long-term albumin infusions have been associated with improved outcomes in decompensated cirrhotic patients. This study aimed to evaluate the impact of albumin infusion on the prognosis of Child-Pugh B patients undergoing treatment with AtezoBev for advanced hepatocellular carcinoma (HCC).

METHODS

We conducted a retrospective multicentric study that included all Child-Pugh B cirrhotic patients treated with AtezoBev since 2020. We examined the effects of albumin infusion (40 g every 3 weeks) on overall survival (OS) and the occurrence of cirrhosis-related complications. Time-to-event data were analyzed using Kaplan-Meier with the log-rank test and Cox models.

RESULTS

Forty-seven HCC patients with a Child-Pugh B score who received AtezoBev were included, of whom 26% also received albumin infusions every 3 weeks. The two groups were similar in terms of liver function and HCC parameters. The median OS was 4.4 and 5.8 months (p = 0.42) for patients who did or did not receive albumin, respectively. The occurrence of hepatic encephalopathy and variceal bleeding was similar between the two groups. However, albumin infusions were associated with a significantly lower rate of ascites expansion/development (13% versus 57%, p = 0.005). Cox analysis revealed that a history of ascites (HR=3.82 [95% CI: 1.73-8.48]) was independently associated with a higher risk of ascites expansion/development, whereas albumin infusions were protective (HR=0.07 [95% CI: 0.01-0.54]).

CONCLUSIONS

Albumin infusion did not improve overall survival in Child-Pugh B HCC patients treated with AtezoBev, but it significantly reduced the expansion/development of ascites.

Baveno VI and VII criteria are not suitable for screening for large varices or clinically significant portal hypertension in patients with hepatocellular carcinoma

BACKGROUND

Baveno VI and VII criteria are used in patients with cirrhosis to rule out large size oesophageal varices (EV) and rule in/out clinically significant portal hypertension (CSPH).

AIM

To evaluate their diagnostic performance in these patients.

METHODS

We retrospectively included all patients with Child-Pugh A cirrhosis and HCC who had endoscopy, liver stiffness measurement (LSM) and platelet count within 6 months. They were classified according to the BCLC stage. Favourable Baveno VI criteria were defined by LSM < 20 kPa and platelets > 150 G/L (to rule out large EV), favourable Baveno VII criteria if LSM ≤ 15 kPa and platelets ≥ 150 G/L (to rule out CSPH, which was defined by a HVPG ≥ 10 mm Hg.

RESULTS

We included 185 patients; 46% were BCLC-0/A, 28% BCLC-B and 26% BCLC-C. EV were present in 44% (23% large), and HVPG ≥ 10 mm Hg in 42% (mean 8 mm Hg). In patients with favourable Baveno VI criteria, 8% of the whole cohort (Se 93%, NPV 92%), 11% of BCLC-0-A (Se 89%, NPV 89%) and 10.0% of BCLC-C patients (Se 91%, NPV 90%) had large EV. Among patients with HVPG < 10 mm Hg, 6% had large EV and 17% small. CSPH was present in 23% of patients with favourable Baveno VII criteria among the whole cohort, and in 25% of those with BCLC-0/A. The specificity of LSM ≥ 25 kPa to rule in CSPH was 48%.

CONCLUSIONS

Favourable Baveno VI criteria are not appropriate to rule out the presence of high-risk EV, or Baveno VII criteria to rule CSPH in/out in patients with HCC.

Ensuring privacy protection in the era of big laparoscopic video data: development and validation of an inside outside discrimination algorithm (IODA)

BACKGROUND

Laparoscopic videos are increasingly being used for surgical artificial intelligence (AI) and big data analysis. The purpose of this study was to ensure data privacy in video recordings of laparoscopic surgery by censoring extraabdominal parts. An inside-outside-discrimination algorithm (IODA) was developed to ensure privacy protection while maximizing the remaining video data.

METHODS

IODAs neural network architecture was based on a pretrained AlexNet augmented with a long-short-term-memory. The data set for algorithm training and testing contained a total of 100 laparoscopic surgery videos of 23 different operations with a total video length of 207 h (124 min ± 100 min per video) resulting in 18,507,217 frames (185,965 ± 149,718 frames per video). Each video frame was tagged either as abdominal cavity, trocar, operation site, outside for cleaning, or translucent trocar. For algorithm testing, a stratified fivefold cross-validation was used.

RESULTS

The distribution of annotated classes were abdominal cavity 81.39%, trocar 1.39%, outside operation site 16.07%, outside for cleaning 1.08%, and translucent trocar 0.07%. Algorithm training on binary or all five classes showed similar excellent results for classifying outside frames with a mean F1-score of 0.96 ± 0.01 and 0.97 ± 0.01, sensitivity of 0.97 ± 0.02 and 0.0.97 ± 0.01, and a false positive rate of 0.99 ± 0.01 and 0.99 ± 0.01, respectively.

CONCLUSION

IODA is able to discriminate between inside and outside with a high certainty. In particular, only a few outside frames are misclassified as inside and therefore at risk for privacy breach. The anonymized videos can be used for multi-centric development of surgical AI, quality management or educational purposes. In contrast to expensive commercial solutions, IODA is made open source and can be improved by the scientific community.

Video-based learning of coping strategies for common errors improves laparoscopy training-a randomized study

AIMS

The aim of this study was to investigate whether shifting the focus to solution orientation and developing coping strategies for common errors could increase the efficiency of laparoscopic training and influence learning motivation. The concept of coping has been particularly defined by the psychologist Richard Lazarus [Lazarus and Folkman in Stress, appraisal, and coping, Springer publishing company, New York, 1984]. Based on this model, we examined the use of observational learning with a coping model for its effectiveness as a basic teaching model in laparoscopic training.

METHODS

55 laparoscopically naive medical students learned a standardized laparoscopic knot tying technique with video-based instructions. The control group was only offered a mastery video that showed the ideal technique and was free from mistakes. The intervention group was instructed on active error analysis and watched freely selectable videos of common errors including solution strategies (coping model) in addition to the mastery videos.

RESULTS

There was no statistically significant difference between the intervention and control groups for number of knot tying attempts until proficiency was reached (18.8 ± 5.5 vs. 21.3 ± 6.5, p = 0.142). However, there was a significantly higher fraction of knots achieving technical proficiency in the intervention group after first use of the coping model (0.7 ± 0.1 vs. 0.6 ± 0.2, p = 0.026). Additionally, the proportion of blinded attempts that met the criteria for technical proficiency was significantly higher for the intervention group at 60.9% vs. 38.0% in control group (p = 0.021). The motivational subscore "interest" of the validated score on current motivation (QCM) was significantly higher for the intervention group (p = 0.032), as well as subjective learning benefit (p = 0.002) and error awareness (p < 0.001).

CONCLUSION

Using video-based learning of coping strategies for common errors improves learning motivation and understanding of the technique with a significant difference in its qualitative implementation in laparoscopy training. The ability to think in a solution-oriented, independent way is necessary in surgery in order to recognize and adequately deal with technical difficulties and complications.

Dynamic alpha factor prediction with operating data - a machine learning approach to model oxygen transfer dynamics in activated sludge

Aeration is an energy-intensive process of aerobic biological wastewater treatment. An accurate model of oxygen transfer dynamics in activated sludge tanks would improve design and operation of aeration systems. Such a model should consider spatial and diurnal variation of α-factor as well as site-specific conditions that impact oxygen transfer. For this dynamic prediction a machine learning approach was used for the first time. The data-driven method was based on long-term ex-situ off-gas measurements with pilot-scale reactors (5.8 m height, 8.3 m³ vol) coupled to full-scale activated sludge tanks on the sites of two conventional and a two-stage activated sludge treatment plant. The ex-situ off-gas method allowed to quantify theoretical off-gas parameters in non-aerated zones and thus consider the whole activated sludge tank. We introduced the α₀-factor to compare aerated and non-aerated zones under nonsteady-state conditions. Like the established α-factor for steady-state conditions, the α₀-factor describes oxygen transfer inhibiting effects in activated sludge. α₀-factor was lowest in upstream denitrification zones. This indicates an anoxic elimination of oxygen transfer inhibiting wastewater contaminants which improved oxygen transfer in subsequent aerobic zones. Random Forest models predicted α₀-factor reliably in all examined activated sludge tanks even for stormwater events and seasonal variation. Model development only required online sensor data already available to operators. Our results suggest that machine learning models can dynamically predict α-factors in a variety of activated sludge processes, thus considering site-specific conditions in model training without manual calibration.

Nurse Preceptors' Experiences of an Online Strength-Based Nursing Course in Clinical Teaching

Background: Online educational programs for nurse preceptors have been created based on various theoretical frameworks; however, no programs using a Strengths-Based Nursing (SBN) approach could be located. Purpose: This qualitative descriptive study explored the nurse preceptors' experiences in using a SBN approach to provide clinical teaching to nursing students after completing an online SBN clinical teaching course. Methods: Semi-structured interviews were conducted with six nurses. Data was thematically analyzed. Findings: Although their levels of familiarity with SBN varied, all preceptors acknowledged that using a SBN approach in clinical teaching benefits both students and educators. They reported that it empowered students and that it allowed them to discover their strengths. Getting to know their students helped the preceptors provide tailored learning experiences and feedback. Using the SBN approach simultaneously enhanced the preceptors' self-confidence and created opportunities for shared learning. Conclusion: Using a strengths' approach offers nurse preceptors a powerful tool to facilitate student learning and skills development in clinical practice.

Serious gaming and virtual reality in the multimodal training of laparoscopic inguinal hernia repair: a randomized crossover study

BACKGROUND

The aim of this study was to assess the transferability of surgical skills for the laparoscopic hernia module between the serious game Touch Surgery™ (TS) and the virtual reality (VR) trainer Lap Mentor™. Furthermore, this study aimed to collect validity evidence and to discuss "sources of validity evidence" for the findings using the laparoscopic inguinal hernia module on TS.

METHODS

In a randomized crossover study, medical students (n = 40) in their clinical years performed laparoscopic inguinal hernia modules on TS and the VR trainer. TS group started with "Laparoscopic Inguinal Hernia Module" on TS (phase 1: Preparation, phase 2: Port Placement and Hernia Repair), performed the module first in training, then in test mode until proficiency was reached. VR group started with "Inguinal Hernia Module" on the VR trainer (task 1: Anatomy Identification, task 2: Incision and Dissection) and also performed the module until proficiency. Once proficiency reached in the first modality, the groups performed the other training modality until reaching proficiency. Primary endpoint was the number of attempts needed to achieve proficiency for each group for each task/phase.

RESULTS

Students starting with TS needed significantly less attempts to reach proficiency for task 1 on the VR trainer than students who started with the VR trainer (TS = 2.7 ± 0.6 vs. VR = 3.2 ± 0.7; p = 0.028). No significant differences for task 2 were observed between groups (TS = 2.3 ± 1.1 vs. VR = 2.1 ± 0.8; p = 0.524). For both phases on TS, no significant skill transfer from the VR trainer to TS was observed. Aspects of validity evidence for the module on TS were collected.

CONCLUSION

The results show that TS brought additional benefit to improve performances on the VR trainer for task 1 but not for task 2. Skill transfer from the VR trainer to TS could not be shown. VR and TS should thus be used in combination with TS first in multimodal training to ensure optimal training conditions.

Baseline ALBI score and early variation of serum AFP predicts outcomes in patients with HCC treated by atezolizumab-bevacizumab

BACKGROUND

The combination of atezolizumab and bevacizumab (AtezoBev) is the current first-line treatment for patients with hepatocellular carcinoma (HCC). Our aim was to evaluate the prognostic role of alpha-foetoprotein (AFP) early response and its combination with albumin-bilirubin (ALBI) in these patients.

METHODS

Patients with HCC under AtezoBev with AFP > 20 ng/ml were included in three centres. The optimal threshold of AFP variation after 3 weeks of treatment was identified for overall survival (OS) and radiological response (RR) using RECIST 1.1 and mRECIST and its ability to predict progression-free survival (PFS) and OS was tested using univariate and multivariate analysis in derivation and validation cohorts.

RESULTS

Seventy-five patients with AFP values >20 ng/ml were included. Fifty-eight patients were male with a median age of 63.5 years; 73% had cirrhosis and HCC stage was classified as BCLC B (18.7%) or C (81.3%). In the derivation cohort (n = 38), a decline in AFP ≥ 20% at 3 weeks (AFP early response) was associated with RR using mRECIST criteria (OR: 13.09 95% CI: 1.44-19.34 p = .02), PFS (HR: 0.42; 95% CI: 0.19-0.93, p = .03) and OS (HR: 0.35; 95% CI: 0.15-0.83, p = .01). AFP early response was confirmed as predictor of RR (p = .02 for mRECIST) and OS (p = .03) in the validation cohort (n= 37). In the whole cohort, the combination of ALBI and AFP early response was significantly associated with OS (p = .046) and PFS (p = .012) with a poor prognosis in patients belonging to the ALBI2-AFP non-responders class.

CONCLUSION

AFP early response at 3 weeks predicts oncological outcomes in HCC patients treated with AtezoBev and combination with ALBI grade refines prognostic discrimination.

Secondary prevention in diabetic and nondiabetic coronary heart disease patients: Insights from the German subset of the hospital arm of the EUROASPIRE IV and V surveys

BACKGROUND

Patients with coronary heart disease (CHD) with and without diabetes mellitus have an increased risk of recurrent events requiring multifactorial secondary prevention of cardiovascular risk factors. We compared prevalences of cardiovascular risk factors and its determinants including lifestyle, pharmacotherapy and diabetes mellitus among patients with chronic CHD examined within the fourth and fifth EUROASPIRE surveys (EA-IV, 2012-13; and EA-V, 2016-17) in Germany.

METHODS

The EA initiative iteratively conducts European-wide multicenter surveys investigating the quality of secondary prevention in chronic CHD patients aged 18 to 79 years. The data collection in Germany was performed during a comprehensive baseline visit at study centers in Würzburg (EA-IV, EA-V), Halle (EA-V), and Tübingen (EA-V).

RESULTS

384 EA-V participants (median age 69.0 years, 81.3% male) and 536 EA-IV participants (median age 68.7 years, 82.3% male) were examined. Comparing EA-IV and EA-V, no relevant differences in risk factor prevalence and lifestyle changes were observed with the exception of lower LDL cholesterol levels in EA-V. Prevalence of unrecognized diabetes was significantly lower in EA-V as compared to EA-IV (11.8% vs. 19.6%) while the proportion of prediabetes was similarly high in the remaining population (62.1% vs. 61.0%).

CONCLUSION

Between 2012 and 2017, a modest decrease in LDL cholesterol levels was observed, while no differences in blood pressure control and body weight were apparent in chronic CHD patients in Germany. Although the prevalence of unrecognized diabetes decreased in the later study period, the proportion of normoglycemic patients was low. As pharmacotherapy appeared fairly well implemented, stronger efforts towards lifestyle interventions, mental health programs and cardiac rehabilitation might help to improve risk factor profiles in chronic CHD patients.

Validation of a screening algorithm for hepatic fibrosis by Doppler ultrasound and elastography in a general population

BACKGROUND

Early detection can prevent the initial stages of fibrosis from progressing to cirrhosis.

PURPOSE

To evaluate an algorithm combining three echographic indicators and elastographic measurements to screen for hepatic fibrosis in an unselected population.

MATERIAL AND METHODS

From May 2017 to June 2018, all patients with no history and no known chronic liver disease who were referred for an ultrasound (US) were prospectively included in eight hospitals. The indicators being sought were liver surface irregularity, demodulation of hepatic veins, and spleen length >110 mm. Patients presenting at least one of these underwent elastography measurements with virtual touch quantification (VTQ) or supersonic shear imaging (SSI). If elastography was positive, patients were referred to hepatologist for fibrosis evaluation. Reference standard was obtained by FibroMeter^VCTE or biopsy. A FibroMeter^VCTE result >0.384 indicated a "necessary referral" to a hepatologist.

RESULTS

Of the 1501 patients included, 504 (33.6%) were positive for at least one US indicator. All of them underwent US elastography, with 85 being positive. Of the patients, 58 (3.6%) had a consultation with a liver specialist: 21 had positive FibroMeter^VCTE and nine had an indication of biopsy for suspicion of fibrosis. This screening algorithm made it possible to diagnose 1.6% of patients in our population with unknown fibrosis. Of the patients, 50% referred to the liver specialist were "necessary referrals."

CONCLUSION

Our study suggests that three simple US indicators with no systematic elastographic measurement could be applied in day-to-day practice to look for hepatic fibrosis in an unsuspected population allowing relevant referrals to a hepatologist.

The Evolution of Feeding Mechanics in the Danioninae, or Why Giant Danios Don't Suck Like Zebrafish

By linking anatomical structure to mechanical performance we can improve our understanding of how selection shapes morphology. Here we examined the functional morphology of feeding in fishes of the subfamily Danioninae (order Cypriniformes) to determine aspects of cranial evolution connected with their trophic diversification. The Danioninae comprise three major lineages and each employs a different feeding strategy. We gathered data on skull form and function from species in each clade, then assessed their evolutionary dynamics using phylogenetic-comparative methods. Differences between clades are strongly associated with differences in jaw protrusion. The paedomorphic Danionella clade does not use jaw protrusion at all, members of the Danio clade use jaw protrusion for suction production and prey capture, and members of the sister clade to Danio (e.g., Devario and Microdevario) use jaw protrusion to retain prey after capture. The shape of the premaxillary bone is a major determinant of protrusion ability, and premaxilla morphology in each of these lineages is consistent with their protrusion strategies. Premaxilla shapes have evolved rapidly, which indicates that they have been subjected to strong selection. We compared premaxilla development in giant danio (Devario aequipinnatus) and zebrafish (Danio rerio) and discuss a developmental mechanism that could shift danionine fishes between the feeding strategies employed by these species and their respective clades. We also identified a highly integrated evolutionary module that has been an important factor in the evolution of trophic mechanics within the Danioninae.

Abdominal Extrarenal Involvement in Erdheim-Chester Disease in a Cohort of 304 Patients

This cohort study estimates the prevalence of nonretroperitoneal abdominal organ involvement in Erdheim-Chester disease in a large cohort of patients.

A history of variceal bleeding is associated with further bleeding under atezolizumab-bevacizumab in patients with HCC

BACKGROUND

Atezolizumab-bevacizumab is the new standard for advanced hepatocellular carcinoma (HCC) but its impact on portal hypertension (PHT) is unknown. We aimed to identify predictive factors of acute variceal bleeding (AVB) and to monitor PHT parameters under treatment.

METHODS

We conducted a prospective study including all cirrhotic patients treated with atezolizumab-bevacizumab since 2020. We performed monitoring of PHT using upper endoscopy at inclusion and at 6 months and hepatic venous pressure gradient (HVPG) at inclusion, 3 and 6 months after the beginning of treatment. We also included a retrospective series of patients treated with sorafenib. Time-to-events data were estimated by Kaplan-Meier with the log-rank test, along with Cox models.

RESULTS

Forty-three patients treated with atezolizumab-bevacizumab were included (male 79.1%, Child-Pugh A 86%). At baseline, 48.8% were treated with curative anticoagulation, 16.3% already experienced AVB and 25.6% had large oesophageal varices (EV). Sorafenib group characteristics were similar. Vascular invasion was present in 60.5% and median was HVPG 8.5 mm Hg. No significant modification in HVPG and EV size was observed at 6 months in the whole cohort but also when considering vascular invasion and radiological response. 14% presented AVB within a median time of occurrence of 3 months, without bleeding-related death. In multivariate analysis, history of AVB (HR = 10.58, p = .03) was associated with AVB. AVB incidence was higher in atezolizumab-bevacizumab compared to sorafenib group (21% vs. 5% at 1 year, p = .02).

CONCLUSIONS

Atezolizumab-bevacizumab treatment was associated with a higher risk of AVB compared to sorafenib. A history of AVB was associated with AVB during follow-up, which questions the use of bevacizumab in this setting.

Reliability of extracellular contrast versus gadoxetic acid in assessing small liver lesions using liver imaging reporting and data system v.2018 and European association for the study of the liver criteria

BACKGROUND & AIMS

The diagnostic accuracy of Liver Imaging Reporting and Data System (LI-RADS) v.2018 and European Association for the Study of the Liver (EASL) criteria for the diagnosis of HCC have been widely evaluated, but their reliability should be investigated. We aimed to assess and compare the reliability of LI-RADS v.2018 and EASL criteria for the diagnosis of HCC using MRI with extracellular contrast agents (ECAs) and gadoxetic acid (GA) and determine the effect of ancillary features on LI-RADS reliability.

APPROACH & RESULTS

Ten readers reviewed MRI studies of 92 focal liver lesions measuring <3 cm acquired with ECAs and GA <1 month apart from two prospective trials, assessing EASL criteria, LI-RADS major and ancillary features, and LI-RADS categorization with and without including ancillary features. Inter-reader agreement for definite HCC diagnosis was substantial and similar for the two contrasts for both EASL and LI-RADS criteria. For ECA-MRI and GA-MRI, respectively, inter-reader agreement was k = 0.72 (95% CI, 0.63-0.81) and k = 0.72 (95% CI, 0.63-0.80); for nonrim hyperenhancement, k = 0.63 (95% CI, 0.54-0.72) and k = 0.57 (95% CI, 0.48-0.66); and for nonperipheral washout, k = 0.49 (95% CI, 0.40-0.59) and k = 0.48 (95% CI, 0.37-0.58) for enhancing capsule. The inter-reader agreement for LI-RADS after applying ancillary features remained in the same range of agreement.

CONCLUSIONS

Agreement for definite HCC was substantial and similar for both scoring systems and the two contrast agents in small focal liver lesions. Agreement for LI-RADS categorization was lower for both contrast agents, and including LI-RADS ancillary features did not improve agreement.

Health inequalities in very old age: Continuity, accumulation or convergence?

Background

Health inequalities are well documented empirically. However, it is unclear whether health inequalities persist in very old age (continuity), whether they accumulate steadily (accumulation), or whether they even attenuate in old age (convergence) - not least because of social inequalities in life expectancy, which make it less likely for individuals with lower social status to reach old age at all. The aim of this study is to empirically test these three hypotheses.

Methods

The analyses are based on representative cross-sectional data from 1,863 very old people and panel data from 912 participants in the 1st and 2nd wave (W1, W2) living in North Rhine-Westphalia the largest federal state in Germany (NRW80+ study). Health outcomes of the analyses are subjective health, multimorbidity and need for long-term care. Indicators of socioeconomic status (SES) are education, occupational status, and net equivalent income. Regression models (linear, logistic, ordinal) are used to analyze cross-sectional and longitudinal data. Panel selectivity is also considered by means of a failure model.

Results

Cross-sectional findings show health inequalities for all SES variables: persons with low education and low income have poorer subjective health and higher need for care. Low status is associated with higher need for care. Preliminary results from longitudinal analyses show a slight increase in health inequality: low income and low status are associated with higher multimorbidity and low education with higher dependency on long-term care at W2.

Conclusions

Despite the socially conditioned unequal chances of reaching old age, health inequality is still present in very old age and even increases slightly over time. The results argue against the convergence hypothesis and in favor of the continuity or even the accumulation hypothesis. A better understanding of the mechanisms leading to the persistent inequality is needed to development targeted interventions also in old age.

Key messages

• Health inequalities persist and even increase in very old age (80+).

• It is imperative that the oldest old – an increasingly large population group – be considered when designing strategies to reduce health inequalities.

Caught between competing emotions and tensions - a focus group study exploring experiences of family caregivers of out-of-hospital cardiac arrest survivors

Funding Acknowledgements

Type of funding sources: None.

Background/Introduction

Being a family member caring for an out-of-hospital cardiac arrest (OHCA) survivor may impact family caregivers’ lives due to the sudden onset of the illness and possible secondary cognitive, emotional and physical challenges. However, experiences of caring for an OHCA survivor are sparsely described.

Purpose

This purpose of this study was to explore the subjective experiences of family caregivers of OHCA survivors as a means of understanding the potential burden they face.

Methods

Using an explorative qualitative approach, six focus group interviews were conducted with a sample of 25 family caregivers of OHCA survivors and analysed using a phenomenological hermeneutic approach inspired by the philosophy of Ricoeur. OHCA survivors and their family caregivers were attenting at a residential rehabilitation course, where the caregivers were interviewed as part of the course.

Results

Three themes emerged: i) Feeling unexpectedly alone and invisible; the family caregivers felt an emotional burden that could not be shared – leading to caregiving being a lonely and anxious experience. The family caregiver felt alone with the responsibility of the shared life, ii) Fear of loss; the fear of losing a loved one was a constant companion contributing to the burden of caregiving, and iii) Adjusting to a new everyday life; the family caregivers had difficulties adjusting to living their lives on the basis of the survivors’ needs. This often resulted in an existential crisis trying to adapt (Figure 1).

Conclusion

The findings of this study illuminate and emphasise the burden experienced by family caregivers and how they can be caught between competing emotions and tensions. The possible caregiver burden following OHCA should be acknowledged.

Systematic screening is needed to identify those at risk of high caregiver burden. Further, collaboration with family care givers should be an essential part of post-cardiac arrest care, and interventions to reduce the burden should be tested and implemented as part of the clinical care of OHCA survivors and their families.

Radiomics Can Distinguish Pediatric Supratentorial Embryonal Tumors, High-Grade Gliomas, and Ependymomas

BACKGROUND AND PURPOSE

Pediatric supratentorial tumors such as embryonal tumors, high-grade gliomas, and ependymomas are difficult to distinguish by histopathology and imaging because of overlapping features. We applied machine learning to uncover MR imaging-based radiomics phenotypes that can differentiate these tumor types.

MATERIALS AND METHODS

Our retrospective cohort of 231 patients from 7 participating institutions had 50 embryonal tumors, 127 high-grade gliomas, and 54 ependymomas. For each tumor volume, we extracted 900 Image Biomarker Standardization Initiative-based PyRadiomics features from T2-weighted and gadolinium-enhanced T1-weighted images. A reduced feature set was obtained by sparse regression analysis and was used as input for 6 candidate classifier models. Training and test sets were randomly allocated from the total cohort in a 75:25 ratio.

RESULTS

The final classifier model for embryonal tumor-versus-high-grade gliomas identified 23 features with an area under the curve of 0.98; the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 0.85, 0.91, 0.79, 0.94, and 0.89, respectively. The classifier for embryonal tumor-versus-ependymomas identified 4 features with an area under the curve of 0.82; the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 0.93, 0.69, 0.76, 0.90, and 0.81, respectively. The classifier for high-grade gliomas-versus-ependymomas identified 35 features with an area under the curve of 0.96; the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 0.82, 0.94, 0.82, 0.94, and 0.91, respectively.

CONCLUSIONS

In this multi-institutional study, we identified distinct radiomic phenotypes that distinguish pediatric supratentorial tumors, high-grade gliomas, and ependymomas with high accuracy. Incorporation of this technique in diagnostic algorithms can improve diagnosis, risk stratification, and treatment planning.

Relationship between psychological characteristics, personality traits, and training on performance in a neonatal resuscitation scenario: A machine learning based analysis

BACKGROUND

In life-threatening emergency events, prompt decision-making and accurate reactions are essential for saving a human's life. Some of these skills can be improved by regular simulation trainings. However, besides these factors, individual characteristics may play a significant role in the patients' outcome after a resuscitation event. This study aimed to differentiate personality characteristics of team members who take responsibility for their actions, contextualizing the effect of training on resuscitation performance.

METHODS

Six hundred and two third-year medical students were asked to answer psychological and personality questionnaires. Fifty-five of them performed in a neonatal simulation resuscitation scenario. To assess participants' performances in the NLS scenario, we used a scenario-based designed NLS checklist. A machine learning design was utilized to better understand the interaction of psychological characteristics and training. The first model aimed to understand how to differentiate between people who take responsibility for their actions vs. those who do not. In a second model, the goal was to understand the relevance of training by contextualizing the effect of training to other important psychological and personality characteristics like locus of control, anxiety, emotion regulation, openness to experience, conscientiousness, extraversion, agreeableness, and neuroticism.

RESULTS

No statistically significant differences were found for psychological characteristics between the training group and the no training group. However, as expected, differences were noted in favor of the training group for performance and within gender for psychological characteristics. When correcting for all these information in a model, anxiety and gender were the most important factors associated with taking responsibility for an action, while training was the only relevant factor in explaining performance during a neonatal resuscitation scenario.

CONCLUSION

Training had a significantly stronger effect on performance in medical students in a neonatal resuscitation scenario than individual characteristics such as demographics, personality, and trait anxiety.

Association of shear-wave elastography with clinical outcomes post-liver transplantation

PURPOSE

Two-dimensional shear-wave elastography (2D-SWE) assessment of liver stiffness has the advantage of being obtained during conventional ultrasound. Liver-stiffness values on 2D-SWE for grafted livers are unknown, as are their potential link to post-transplantation morbidity. This study was undertaken to determine liver-stiffness values on 2D-SWE for grafted livers without complications, and examine relationships between liver-stiffness values on 2D-SWE and early post-operative arterial or biliary complications.

METHODS

In our facility, all liver-transplant recipients are entered in a comprehensive surgical database, where donor, procedure and recipient characteristics are described. All patients underwent systematic 2D-SWE assessment. Potential relationships were analyzed between liver-stiffness findings and donor, procedure and recipient characteristics, and follow-up events, including death, arterial or biliary complications, graft removal and allograft-dysfunction scores.

RESULTS

Liver-stiffness values on 2D-SWE of 337 ultrasound examinations from 165 liver-transplant recipients were collected retrospectively. Median time from transplantation to 2D-SWE examination was 149 days, with median follow-up at 36 months. The mean±SD stiffness value for grafts without complications was 7.3±2.3kPa; it was significantly higher during the first 90 days (8.2±2.5kPa) post-transplant than after 1year (7.0±2.4kPa) (P=0.01). Patients with biliary complications during the first-year post-transplantation had significantly higher mean liver-stiffness values on 2D-SWE than those without, respectively: 9.8±7.0 vs 7.5±1.8kPa (P=0.01).

CONCLUSIONS

Post-transplantation patients without complications had stiffer livers than the general population, with higher values during the first 90 days after surgery. Liver-stiffness values on 2D-SWE were significantly higher for patients with biliary, but not arterial, complications.

Triangle Singularity as the Origin of the a_{1}(1420)

The COMPASS Collaboration experiment recently discovered a new isovector resonancelike signal with axial-vector quantum numbers, the a_{1}(1420), decaying to f_{0}(980)π. With a mass too close to and a width smaller than the axial-vector ground state a_{1}(1260), it was immediately interpreted as a new light exotic meson, similar to the X, Y, Z states in the hidden-charm sector. We show that a resonancelike signal fully matching the experimental data is produced by the decay of the a_{1}(1260) resonance into K^{*}(→Kπ)K[over ¯] and subsequent rescattering through a triangle singularity into the coupled f_{0}(980)π channel. The amplitude for this process is calculated using a new approach based on dispersion relations. The triangle-singularity model is fitted to the partial-wave data of the COMPASS experiment. Despite having fewer parameters, this fit shows a slightly better quality than the one using a resonance hypothesis and thus eliminates the need for an additional resonance in order to describe the data. We thereby demonstrate for the first time in the light-meson sector that a resonancelike structure in the experimental data can be described by rescattering through a triangle singularity, providing evidence for a genuine three-body effect.