Papers by Yolande Lievens
Survival Prediction in Lung Cancer Treated with Radiotherapy: Bayesian Networks vs. Support Vector Machines in Handling Missing Data
Abstract Missing data is a given in the medical domain, so machine learning models should have sa... more Abstract Missing data is a given in the medical domain, so machine learning models should have satisfactory performance even when missing data occurs. Our previous work has focused on support vector machines (SVM), but we hypothesize that Bayesian networks ( ...
Radiotherapy and Oncology, 2016
Radiotherapy and Oncology, 2015
3rd ESTRO Forum 2015 S43 physiological methods and validated questionnaires. Ten single nucleotid... more 3rd ESTRO Forum 2015 S43 physiological methods and validated questionnaires. Ten single nucleotide polymorphisms (SNPs) have previously been suggested to be predictive of late radiation induced toxicity by GWAS studies or candidate gene studies. The objective of this study was to test the ten SNPs in this unique cohort. The strength of the reportings as well as the clinical data available served as the rationale for using our rather small cohort as a validation cohort. Materials and Methods: The patients in this cohort have received EBRT 70-78 Gy for prostate cancer with curative intent. Functional toxicity endpoints have been examined by sigmoidoscopy, manometry, endoanal ultrasonography and impedance planimetry in an earlier study. Objective endpoints include the Vienna Rectoscopy Score (VRS), cross sectional area (CSA) of rectum at distension, maximum resting pressure (MRP) and maximum squeezing pressure (MSP) of anal sphincters. The subjective measure RT-Anorectal dysfunction score (RT-ARD) was obtained from the questionnaires. Biological material from the patients in this cohort is available from an established research biobank. The SNPs were investigated in DNA from fibroblasts with TaqMan SNP assays. Statistical analyses was carried out with Stata13. For each SNP (table I) the reported risk allele was identified and due to the small sample size a risk-allele average was created for each patient. This risk-allele average was correlated to RT-ARD, VRS, MRP, MSP and CSA by Spearman's rank correlation.
Radiotherapy and Oncology, 2016
Radiotherapy and Oncology, 2015
3rd ESTRO Forum 2015 Cardiac serum biomarker results will not be available for this cohort of pat... more 3rd ESTRO Forum 2015 Cardiac serum biomarker results will not be available for this cohort of patients. Cardiac MRI is performed on a Siemens 3.0 Tesla scanner. The imaging protocol includes short axis scans of the base, mid and apical positions of the left ventricle and 4-chamber scan, including standard cine scans for anatomy, mass and function. The cardiac MRI images are registered with the radiotherapy planning CT scan and analysed for the radiotherapy dose to cardiac macrostructures and the left ventricle 17 segment model. The radiotherapy dose will be correlated with cardiac MRI, ECG and cardiac biomarkers. Results: To date 24 patients have been recruited, 7 were withdrawn due to issues with completion of cardiac MRI scan, and 5 have completed the study. On treatment radiotherapy physics data has been analysed for 12 of these patients. Maximum radiotherapy dose was highest in the left (mean 4680cGy, 95CI (3711-5649) and right atria (mean 3885cGy, 95CI 2635-5135) compared to the left (mean 2625 cGy, 95CI 1567-3682) and right ventricles (mean 2448 cGy, 95CI 1678-3217) (p=0.005 and p=0.021 respectively). Furthermore review of the dose to the left ventricular segments, identified areas which received radiation dose in excess of 35Gy. Cardiac function, measured by cardiac MRI, was significantly affected during radiotherapy. There was a small but significant relative reduction in LVEF compared to baseline (-4.7%, p=0.040). In comparison, right sided cardiac function was more impaired, with a mean relative fall in RVEF of 21.6% (95CI 13.01-30.26, p < 0.0001). Conclusions: Preliminary evidence suggests an acute effect on right heart function by thoracic radiotherapy in NSCLC. Further analyses will be performed as the data matures.
Cancer Imaging, 2012
Stereotactic ablative body radiotherapy (SABR) represents a technological breakthrough in radioth... more Stereotactic ablative body radiotherapy (SABR) represents a technological breakthrough in radiotherapy technique, with proven benefits to patients in terms of improved tumour control and overall survival. The key components of SABR are described. The current evidence base for SABR for the treatment of primary and secondary lung tumours is appraised, and key ongoing trials are identified.
UGent, 3 UAntwerpen, 4 private consultant, 5 UC Louvain, 6 UCL-St.Luc RÉSUMÉ Contexte général 1. ... more UGent, 3 UAntwerpen, 4 private consultant, 5 UC Louvain, 6 UCL-St.Luc RÉSUMÉ Contexte général 1. L'hadronthérapie est un nom générique qui englobe les traitements par faisceaux de hadrons. Les hadrons sont des particules susceptibles d'interaction forte (άδρός = fort), à savoir, en pratique, protons, neutrons ou noyaux atomiques. À l'heure actuelle, les protons et les ions carbone sont les plus investigués. 2. En 2012, la Belgique comptait 25 centres de radiothérapie externe et 11 satellites traitant environ 30,000 patients/an par photons ou électrons. L'hadronthérapie n'est pas disponible en Belgique. 3. L'Europe comptait 14 centres d'hadronthérapie opérationnels (protons: 12, ions carbone et protons: 2). Le coût est de 18,000-40,000 €/patient. Les USA sont le leader mondial en protonthérapie; les coûts/patient y dépassent souvent les 100,000 $. Le Japon est le leader mondial en thérapie par ions carbone. Les coûts/patient y sont d'environ 40,000 €, soutien logistique inclus. 4. Très peu de patients belges sont adressés à des centres d'hadronthérapie en raison de difficultés multiples : listes d'attente, barrières linguistiques, déplacements longs, hébergement coûteux, raisons sociales, problèmes logistiques et financiers.
Radiotherapy and Oncology, 2021
Radiotherapy interventions are rapidly evolving and improving, holding promise for better patient... more Radiotherapy interventions are rapidly evolving and improving, holding promise for better patient outcomes, yet at the possible detriment of higher societal costs. The ESTRO-HERO value-based radiotherapy project aims to develop a framework defining and assessing the value of radiotherapy innovations, to support clinical implementation and equitable access, within a sustainable healthcare system.
Radiotherapy and Oncology, 2015
24 Cost and economic evaluation of radiotherapy. Activity-based costing and modelling techniques
European Journal of Cancer Supplements, 2003
International journal of radiation oncology, biology, physics, Jan 15, 2018
Radiation therapy is a core modality of cancer treatment; however, concerns have been expressed r... more Radiation therapy is a core modality of cancer treatment; however, concerns have been expressed regarding its underutilization and its lack of prioritization as a research domain relative to other cancer treatment modalities, despite its rapid technical evolution. It is therefore important to understand, from a public policy perspective, the evolution of global radiation therapy research, to identify strengths, weaknesses, and opportunities. This study used a bibliometric approach to undertake a quantitative analysis of global radiation therapy research published between 2001 and 2015 and available in the Web of Science (Wos) database, with particular focus on the 25 leading research-active countries. A total of 62,550 radiation therapy research articles from 127 countries, published in 2531 international journals, were analyzed. The United States was responsible for 32.3% of these outputs, followed by Japan (8.0%) and Germany (7.7%). Nearly half of all publications related to prepa...
International journal of radiation oncology, biology, physics, Jan 15, 2018
Radiation therapy is a core modality of cancer treatment; however, concerns have been expressed r... more Radiation therapy is a core modality of cancer treatment; however, concerns have been expressed regarding its underutilization and its lack of prioritization as a research domain relative to other cancer treatment modalities, despite its rapid technical evolution. It is therefore important to understand, from a public policy perspective, the evolution of global radiation therapy research, to identify strengths, weaknesses, and opportunities. This study used a bibliometric approach to undertake a quantitative analysis of global radiation therapy research published between 2001 and 2015 and available in the Web of Science (Wos) database, with particular focus on the 25 leading research-active countries. A total of 62,550 radiation therapy research articles from 127 countries, published in 2531 international journals, were analyzed. The United States was responsible for 32.3% of these outputs, followed by Japan (8.0%) and Germany (7.7%). Nearly half of all publications related to prepa...
O-062 Economic assessment of first-line chemotherapy in symptomaticadvanced stage NSCLC in Belgium: A cost-utility analysis (CUA)
Lung Cancer
Cost evaluation to optimise radiation therapy implementation in different income settings: A time-driven activity-based analysis
Radiotherapy and Oncology
80INBUDGET Impact vs Cost Effectiveness: Implications for Personalised Cancer Therapies
Annals of Oncology
Cost evaluations of radiotherapy: What do we know? An ESTRO-HERO analysis
Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology, Dec 1, 2016
Although economic evidence is becoming mandatory to support health care decision-making, challeng... more Although economic evidence is becoming mandatory to support health care decision-making, challenges remain in generating high quality cost data, especially for complex and rapidly evolving treatment modalities, such as radiotherapy. The overall aim of this systematic literature review was to critically analyse the type and quality of radiotherapy cost information available in cost calculation studies, from the health care provider's perspective, published since 1981. A selection process, based on strict and explicit criteria, yielded 52 articles. In spite of meeting our criteria these studies displayed large heterogeneity in scope, costing method, inputs and outputs. The limited use of conventional costing methodologies along with insufficient information on resource inputs hampered comparability across studies. A consistent picture of radiotherapy costs, based on methodologically sound costing studies, has yet to emerge. These results call for developing a well-defined and gene...
Highly Accelerated Irradiation in 5 fractions (HAI-5): feasibility in elderly women with early or locally-advanced breast cancer
International Journal of Radiation Oncology*Biology*Physics, 2017
To investigate, in a prospective phase 1 to 2 trial, the safety and feasibility of delivering ext... more To investigate, in a prospective phase 1 to 2 trial, the safety and feasibility of delivering external beam radiation therapy in 5 fractions to the breast or thoracic wall, including boost and/or lymph nodes if needed, to women aged ≥65 years with breast cancer. Ninety-five patients aged ≥65 years, referred for adjuvant radiation therapy, were treated in 5 fractions over 12 days with a total dose of 28.5 Gy/5.7 Gy to the breast or thoracic wall and, if indicated, 27 Gy/5.4 Gy to the lymph node regions and 32.5 Gy/6.5 Gy to 34.5 Gy/6.9 Gy to the tumor bed. The primary endpoint was clinically relevant dermatitis (grade ≥2). Mean follow-up time was 5.6 months, and mean age was 73.6 years. Clinically relevant dermatitis was observed in 11.6% of patients and only occurred in breast irradiation with boost (17.5% grade 2-3 vs 0% in the no-boost group). Although doses were high, treatment delivery with intensity modulated radiation therapy was swift, except for complex treatments, including lymph nodes for which single-arc volumetric modulated arc therapy was needed to reduce beam-on time. Accelerated radiation therapy in 5 fractions was technically feasible and resulted in low acute toxicity. Clinically relevant erythema was only observed in patients receiving a boost, but still at an acceptable rate. Although the follow-up is still short, the results on acute toxicity after accelerated radiation therapy were encouraging. A 5-fraction schedule is well tolerated in the elderly and may lower the threshold for radiation therapy in this population.
Acta oncologica (Stockholm, Sweden), Jan 20, 2017
In early-stage classical Hodgkin lymphoma (HL) the target volume nowadays consists of the volume ... more In early-stage classical Hodgkin lymphoma (HL) the target volume nowadays consists of the volume of the originally involved nodes. Delineation of this volume on a post-chemotherapy CT-scan is challenging. We report on the interobserver variability in target volume definition and its impact on resulting treatment plans. Two representative cases were selected (1: male, stage IB, localization: left axilla; 2: female, stage IIB, localizations: mediastinum and bilateral neck). Eight experienced observers individually defined the clinical target volume (CTV) using involved-node radiotherapy (INRT) as defined by the EORTC-GELA guidelines for the H10 trial. A consensus contour was generated and the standard deviation computed. We investigated the overlap between observer and consensus contour [Sørensen-Dice coefficient (DSC)] and the magnitude of gross deviations between the surfaces of the observer and consensus contour (Hausdorff distance). 3D-conformal (3D-CRT) and intensity-modulated ra...
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Papers by Yolande Lievens