Dirk Van Gestel

Publications (6) View all

• Article: RapidArc, SmartArc and TomoHD compared with classical step and shoot and sliding window intensity modulated radiotherapy in an oropharyngeal cancer treatment plan comparison.

  Dirk Van Gestel, Corine van Vliet-Vroegindeweij, Frank Van den Heuvel, Wouter Crijns, Ann Coelmont, Bie De Ost, Andrea Holt, Emmy Lamers, Yasmyne Geussens, Sandra Nuyts, Danielle Van den Weyngaert, Tim Van den Wyngaert, Jan B Vermorken, Vincent Gregoire
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  ABSTRACT: Backround: Radiotherapy techniques have evolved rapidly over the last decade with the introduction of Intensity Modulated RadioTherapy (IMRT) in different forms. It is not clear which of the IMRT techniques is superior in the treatment of head and neck cancer patients in terms of coverage of the planning target volumes (PTVs), sparing the organs at risk (OARs), dose to the normal tissue, number of monitor units needed and delivery time.The present paper aims to compare Step and Shoot (SS) IMRT, Sliding Window (SW) IMRT, RapidArc (RA) planned with Eclipse, Elekta VMAT planned with SmartArc (SA) and helical TomoHDTM (HT). METHODS: Target volumes and organs at risk (OARs) of five patients with oropharyngeal cancer were delineated on contrast enhanced CT-scans, then treatment plans were generated on five different IMRT systems. In 32 fractions, 69.12 Gy and 56 Gy were planned to the therapeutic and prophylactic PTVs, respectively. For the PTVs and 26 OARs ICRU 83 reporting guidelines were followed. Differences in the studied parameters between treatment planning systems were analysed using repeated measures ANOVA. RESULTS: Mean Homogeneity Index of PTVtherapeutic is better with HT(.06) followed by SA(.08), RA(.10), SW(.10) and SS(.11). PTVprophylactic is most homogeneous with RA. Parotid glands prescribed mean doses are only obtained by SA and HT, 20.6 Gy and 21.7 Gy for the contralateral and 25.6 Gy and 24.1 Gy for the ipsilateral, against 25.6 Gy and 32.0 Gy for RA, 26.4 Gy and 34.6 Gy for SW, and 28.2 Gy and 34.0 Gy for SS. RA uses the least monitor units, HT the most. Treatment times are 3.05 min for RA, and 5.9 min for SA and HT. CONCLUSIONS: In the treatment of oropharyngeal cancer, we consider rotational IMRT techniques preferable to fixed gantry techniques due to faster fraction delivery and better sparing of OARs without a higher integral dose. TomoHD gives most homogeneous target coverage with more sparing of spinal cord, brainstem, parotids and the lower swallowing apparatus than most of the other systems. Between RA and SA, SA gives a more homogeneous PTVtherapeutic while sparing the parotids more, but the delivery of RA is twice as fast with less overdose to the PTVelective.
  Radiation Oncology 02/2013; 8(1):37. · 2.32 Impact Factor
• Article: Multi-institutional comparison of volumetric modulated arc therapy vs. intensity-modulated radiation therapy for head-and-neck cancer: a planning study.

  Andrea Holt, Dirk Van Gestel, Mark P Arends, Erik W Korevaar, Danny Schuring, Martina C Kunze-Busch, Rob Jw Louwe, Corine van Vliet-Vroegindeweij
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  ABSTRACT: BACKGROUND: Compared to Intensity-Modulated Radiation Therapy (IMRT), the main advantage of Volumetric Modulated Arc Therapy (VMAT) is a shortened delivery time, which leads to improved patient comfort and possibly smaller intra-fraction movements. This study aims at a treatment planner-independent comparison of radiotherapy treatment planning of IMRT and VMAT for head-and-neck cancer performed by several institutes and based on the same CT- and contouring data. METHODS: Five institutes generated IMRT and VMAT plans for five oropharyngeal cancer patients using either Pinnacle3 or Oncentra Masterplan to be delivered on Elekta linear accelerators. RESULTS: Comparison of VMAT and IMRT plans within the same patient and institute showed significantly better sparing for almost all OARs with VMAT. The average mean dose to the parotid glands and oral cavity was reduced from 27.2 Gy and 39.4 Gy for IMRT to 25.0 Gy and 36.7 Gy for VMAT, respectively. The dose conformity at 95% of the prescribed dose for PTVboost and PTVtotal was 1.45 and 1.62 for IMRT and 1.37 and 1.50 for VMAT, respectively. The average effective delivery time was reduced from 13:15 min for IMRT to 5:54 min for VMAT. CONCLUSIONS: Independently of institution-specific optimization strategies, the quality of the VMAT plans including double arcs was superior to step-and-shoot IMRT plans including 5--9 beam ports, while the effective treatment delivery time was shortened by ~50% with VMAT.
  Radiation Oncology 01/2013; 8(1):26. · 2.32 Impact Factor
• Article: DNA methylation-based biomarkers in serum of patients with breast cancer.

  Lien Van De Voorde, Reinhart Speeckaert, Dirk Van Gestel, Marc Bracke, Wilfried De Neve, Joris Delanghe, Marijn Speeckaert
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  ABSTRACT: Alterations of genetic and epigenetic features can provide important insights into the natural history of breast cancer. Although DNA methylation analysis is a rapidly developing field, a reproducible epigenetic blood-based assay for diagnosis and follow-up of breast cancer has yet to be successfully developed into a routine clinical test. The aim of this study was to review multiple serum DNA methylation assays and to highlight the value of those novel biomarkers in diagnosis, prognosis and prediction of therapeutic outcome. Serum is readily accessible for molecular diagnosis in all individuals from a peripheral blood sample. The list of hypermethylated genes in breast cancer is heterogeneous and no single gene is methylated in all breast cancer types. There is increasing evidence that a panel of epigenetic markers is essential to achieve a higher sensitivity and specificity in breast cancer detection. However, the reported percentages of methylation are highly variable, which can be partly explained by the different sensitivities and the different intra-/inter-assay coefficients of variability of the analysis methods. Moreover, there is a striking lack of receiver operating characteristic (ROC) curves of the proposed biomarkers. Another point of criticism is the fact that 'normal' patterns of DNA methylation of some tumor suppressor and other cancer-related genes are influenced by several factors and are often poorly characterized. A relatively frequent methylation of those genes has been observed in high-risk asymptomatic women. Finally, there is a call for larger prospective cohort studies to determine methylation patterns during treatment and follow-up. Identification of patterns specific for a differential response to therapeutic interventions should be useful. Only in this way, it will be possible to evaluate the predictive and prognostic characteristics of those novel promising biomarkers.
  Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis 06/2012; 751(2):304-25. · 2.85 Impact Factor
• Article: DNA methylation-based biomarkers in serum of patients with breast cancer

  Lien Van De Voorde, Reinhart Speeckaert, Dirk Van Gestel, Marc Bracke, Wilfried De Neve, Joris R Delanghe, Marijn M Speeckaert
  [show abstract] [hide abstract]
  ABSTRACT: Alterations of genetic and epigenetic features can provide important insights into the natural history of breast cancer. Although DNA methylation analysis is a rapidly developing field, a reproducible epigenetic blood-based assay for diagnosis and follow-up of breast cancer has yet to be successfully developed into a routine clinical test. The aim of this study was to review multiple serum DNA methylation assays and to highlight the value of those novel biomarkers in diagnosis, prognosis and prediction of therapeutic outcome. Serum is readily accessible for molecular diagnosis in all individuals from a peripheral blood sample. The list of hypermethylated genes in breast cancer is heterogeneous and no single gene is methylated in all breast cancer types. There is increasing evidence that a panel of epigenetic markers is essential to achieve a higher sensitivity and specificity in breast cancer detection. However, the reported percentages of methylation are highly variable, which can be partly explained by the different sensitivities and the different intra-/inter-assay coefficients of variability of the analysis methods. Moreover, there is a striking lack of receiver operating characteristic (ROC) curves of the proposed biomarkers. Another point of criticism is the fact that 'normal' patterns of DNA methylation of some tumor suppressor and other cancer-related genes are influenced by several factors and are often poorly characterized. A relatively frequent methylation of those genes has been observed in high-risk asymptomatic women. Finally, there is a call for larger prospective cohort studies to determine methylation patterns during treatment and follow-up. Identification of patterns specific for a differential response to therapeutic interventions should be useful. Only in this way, it will be possible to evaluate the predictive and prognostic characteristics of those novel promising biomarkers.
  Mutation Research/Reviews in Mutation Research 01/2012; · 6.46 Impact Factor
• Article: Intensity-modulated radiotherapy in patients with head and neck cancer: a European single-centre experience.

  D Van Gestel, D Van Den Weyngaert, D Schrijvers, J Weyler, J B Vermorken
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  ABSTRACT: The purpose of this study was to analyse retrospectively the intensity-modulated radiotherapy (IMRT) results in patients with head and neck cancer (HNC) treated between November 2003 and June 2007. Patients with early and locoregionally advanced HNC were treated with inverse-planned step-and-shoot IMRT. The prescribed dose varied from 66 Gy to 70 Gy in those receiving IMRT as definitive treatment and from 60 Gy to 70 Gy in the post-operative setting. IMRT was given alone, after induction chemotherapy (ICT), with concomitant chemotherapy (CRT) or with both. Acute and late toxicities are reported; locoregional control (LRC), locoregional relapse-free survival (LRRFS) and overall survival (OS) were calculated from the start of radiation. IMRT was used in 78 patients (48 as definitive treatment, 30 post-operatively), of whom 20 also received ICT and 35 CRT. Three patients stopped IMRT early, one for toxicity (mucosa). Acute toxicity scoring revealed 5 cases (6%) of severe skin toxicity and 65 cases (83%) of severe mucosal toxicity. After a median follow-up of 18.7 months, late toxicities included xerostomia (44%), loss of taste (14%) and fibrosis of the neck (9%). 16 patients had died, of whom 10 due to tumour recurrence/progression and 2 due to treatment (but not IMRT related). The LRC, LRRFS and OS at 3 years are 66.1%, 48.5% and 60.3% in the definitive IMRT group and 85.4%, 82.5% and 85.9% in the post-operative setting, respectively. We consider IMRT for locoregional HNC feasible not only as a single modality but also after surgery, after induction chemotherapy and concurrently with chemotherapy.
  The British journal of radiology 04/2011; 84(1000):367-74. · 2.11 Impact Factor