Mischa S Hoogeman

Erasmus University Rotterdam | EUR · Erasmus MC Cancer Institute

Background and purpose: Osteoradionecrosis (ORN) of the mandible is a severe complication following radiotherapy (RT). With a renewed interest in hypofractionation for head and neck radiotherapy, more information concerning ORN development after high fraction doses is important. The aim of this explorative study was to develop a model for ORN risk...

Objective: Increasing cancer incidence, staff shortage and high burnout rate among radiation oncologists, medical physicists and radiation technicians is putting many departments under strain. Operations research (OR) tools could optimize radiotherapy processes, however, clinical implementation of OR-tools in radiotherapy is scarce since most inves...

Objective: The Dutch proton robustness evaluation protocol prescribes the dose of the clinical target volume (CTV) to the voxel-wise minimum (VWmin) dose of 28 scenarios. This results in a consistent but conservative near-minimum CTV dose (D98%,CTV). In this study, we analyzed: (i) correlations between VWmin/VWmax metrics and actually delivered dos...

Background and purpose To quantify the increase in bladder and rectum dose of a bone marrow sparing (BMS) VMAT strategy for primary treatment of locally advanced cervical cancer (LACC). Materials and methods Twenty patients with stage IB-IVA cervical cancer were selected for this study. The whole Pelvic Bones (PB) was taken as substitute for bone...

Background Radiotherapy (RT) is the standard of care for most advanced head and neck squamous cell carcinoma (HNSCC) and results in an unfavorable 5-year overall survival of 40%. Despite strong biological rationale, combining RT with immune checkpoint inhibitors does not result in a survival benefit. Our hypothesis is that the combination of these...

Background and purpose: In the Netherlands, head-and-neck cancer (HNC) patients are referred for proton therapy (PT) through model-based selection (MBS). However, treatment errors may compromise adequate CTV dose. Our aims are: (i) to derive probabilistic plan evaluation metrics on the CTV consistent with clinical metrics; (ii) to evaluate plan co...

Purpose: Osteoradionecrosis (ORN) of the mandible is a severe complication following radiotherapy, but not all regions of the mandible may be equally at risk. Therefore our goal was to explore a local dose response relationship for subregions of the mandible. Materials and methods: All oropharyngeal cancer patients treated at our hospital betwee...

ESTRO 35 2016 S27 ______________________________________________________________________________________________________ biological imaging to target an ablative dose at known regions of significant tumour burden and a lower, therapeutic dose to low-risk regions. We describe our methods for defining target volume and prescription dose. Material and...

Objective: In radiotherapy, the internal movement of organs between treatment sessions causes errors in the final radiation dose delivery. To assess the need for adaptation, motion models can be used to simulate dominant motion patterns and assess anatomical robustness before delivery. Traditionally, such models are based on principal component ana...

Background: Modelling studies suggest that advanced intensity-modulated radiotherapy may increase second primary cancer (SPC) risks, due to increased radiation exposure of tissues located outside the treatment fields. In the current study we investigated the association between SPC risks and characteristics of applied external beam radiotherapy (E...

HollandPTC is an independent outpatient center for proton therapy, scientific research, and education. Patients with different types of cancer are treated with Intensity Modulated Proton Therapy (IMPT). In addition, the HollandPTC R&D consortium conducts scientific research into the added value and improvements of proton therapy. To this end, Holla...

Background and purpose: Image-guided adaptive brachytherapy (IGABT) is an important modality in the cervical cancer treatment, and plan quality is sensitive to time pressure in the workflow. Patient anatomy-based quality-assurance (QA) with overlap volume histograms (OVHs) has been demonstrated to detect suboptimal plans (outliers). This analysis...

Aims: External beam radiotherapy (EBRT) for prostate cancer (PCa) has rapidly advanced over the years. Advanced techniques with altered dose distributions may have an impact on second haematological cancer (SHC) risks. We assessed SHC risk after EBRT for PCa and explored whether this risk has changed over the years. Materials and methods: Patien...

Perfusion MRI is promising for the assessment, prediction, and monitoring of radiation toxicity in organs at risk in head and neck cancer. Arterial spin labeling (ASL) may be an attractive alternative for conventional perfusion MRI, that does not require administration of contrast agents. However, currently, little is known about the characteristic...

Background/purpose: Post radiation mucosal ulcers (PRMU) after treatment for oropharyngeal squamous cell carcinoma (OPSCC) can have a huge negative impact on patients' quality of life, but little is known concerning risk factors and the impact of fraction size. Therefore, the goal of this study was to determine the pattern of PRMU development and...

Background: Radiotherapy (RT) is standard of care for most advanced head and neck squamous cell carcinoma (HNSCC) and results in an unfavorable 5-year overall survival of 40%. Despite strong biological rationale, combining RT with immune checkpoint inhibitors does not result in a survival benefit. Our hypothesis is that the combination of these ind...

In radiotherapy, the internal movement of organs between treatment sessions causes errors in the final radiation dose delivery. Motion models can be used to simulate motion patterns and assess anatomical robustness before delivery. Traditionally, such models are based on principal component analysis (PCA) and are either patient-specific (requiring...

Background and purpose In intensity modulated proton therapy (IMPT), the impact of setup errors and anatomical changes is commonly mitigated by robust optimization with population-based setup robustness (SR) settings and offline replanning. In this study we propose and evaluate an alternative approach based on daily plan selection from patient-spec...

Purpose and objective Besides a dose-rate threshold of 40-100 Gy/s, the FLASH effect may require a dose >3.5-7 Gy. Even in hypofractioned treatments, with all beams delivered in each fraction (ABEF), most healthy tissue is irradiated to a lower fraction dose. This can be circumvented by single-beam-per-fraction (SBPF) delivery, with a loss of healt...

Purpose FLASH dose rates >40 Gy/s are readily available in proton therapy (PT) with cyclotron-accelerated beams and pencil-beam scanning (PBS). The PBS delivery pattern will affect the local dose rate, as quantified by the PBS dose rate (PBS-DR), and therefore needs to be accounted for in FLASH-PT with PBS, but it is not yet clear how. Our aim was...

Background and Purpose Stereotactic body radiotherapy (SBRT) has been proven to be beneficial for several disease sites in the (lower) abdomen. However, the quality of the treatment plan, based on a single planning computed tomography (CT), can be compromised due to large inter-fraction motion of the target and organs at risk (OARs) in this anatomi...

Purpose To determine the dosimetric impact of using unedited autocontours in daily plan adaptation of patients with locally advanced pancreatic cancer (LAPC) treated with stereotactic body radiotherapy using tumor tracking. Materials and Methods The study included 98 daily CT scans of 35 LAPC patients. All scans were manually contoured (MAN), and...

Introduction The locoregional failure (LRF) rate in human papilloma virus (HPV)-negative oropharyngeal squamous cell carcinoma (OPSCC) remains disappointingly high and toxicity is substantial. Response prediction prior to or early during treatment would provide opportunities for personalised treatment. Currently, there are no accurate predictive mo...

Aims The 15-year results of the EORTC 229922-10925 phase III trial showed a significant reduction in breast cancer mortality and breast cancer recurrences after internal mammary chain (IMC) and medio-supraclavicular irradiation. Unexpectedly, cardiac death was not increased, and the incidence of cardiac events did not differ between left- and right...

Purpose To investigate the potential clinical benefit of a two-beam arrangement technique using three-dimensional (3D) imaging of uveal melanoma (UM) patients treated with proton therapy and a dedicated eyeline. Material/Methods Retrospective CT-based treatment plans of 39 UM patients performed using a single beam (SB) were compared to plans with...

A review of studies on seminal vesicle motion was performed to improve the understanding of these treatment uncertainties. This will aid planning target volume margin reduction, which is necessary for hypofractionation of high-risk prostate cancer. Embase, Medline, Web of science Core collection, Cochrane CENTRAL register of trials and Google schol...

Background and purpose Image-guided adaptive brachytherapy (IGABT) is a key component in the treatment of cervical cancer, but the nature of the clinical workflow makes it vulnerable to suboptimal plans, as the theoretical optimal plan depends heavily on organ configuration. Patient anatomy-based quality-assurance (QA) with overlap volume histogram...

Background/purpose Intensity-modulated proton therapy is highly sensitive to anatomical variations. A dose restoration method and a full plan adaptation method have been developed earlier, both requiring several parameter settings. This study evaluates the validity of the previously selected settings by systematically comparing them to alternatives...

Background and purpose A potential challenge in single-isocenter multi-lesion lung stereotactic body radiotherapy (SBRT) is that patient positioning is not based on each lesion individually, but on the average position of all lesions. This may lead to larger margins compared to treating with one isocenter per lesion, but increases workflow efficien...

Purpose: External Beam Radiotherapy (EBRT) techniques dramatically changed over the years. This may have affected the risk of radiation-induced second primary cancers (SPC), due to increased irradiated low dose volumes and scatter radiation. We investigated whether patterns of SPC after EBRT have changed over the years in prostate cancer (PCa) sur...

Breathing interplay effects in Intensity Modulated Proton Therapy (IMPT) arise from the interaction between target motion and the scanning beam. Assessing the detrimental effect of interplay and the clinical robustness of several mitigation techniques requires statistical evaluation procedures that take into account the variability of breathing dur...

Purpose/Objective(s) Inter-institutional quality assurance (QA) of brachytherapy (BT) treatment planning is often based on expert judgment of a limited number of treatment plans. Cohort comparisons are of limited value as patient anatomy has a major impact on organs-at-risk (OAR) dose. Therefore, the aim of this study was to develop and test a QA t...

Background Due to its specific physical characteristics, proton irradiation is especially suited for irradiation of chordomas and chondrosarcoma in the axial skeleton. Robust plan optimization renders the proton beam therapy more predictable upon individual setup errors. Reported experience with the planning and delivery of robustly optimized plans...

External beam radiation therapy (EBRT) with concurrent chemotherapy followed by brachytherapy is a very effective treatment for locally advanced cervical cancer (LACC). However, treatment-related toxicity is common and reduces the patient’s quality of life (QoL) and ability to complete treatment or undergo adjuvant therapies. Intensity modulated pr...

Patients with locally advanced cervical cancer (LACC) treated with chemoradiation often experience hematologic toxicity (HT), as chemoradiation can induce bone marrow (BM) suppression. Studies on the relationship between BM dosimetric parameters and clinically significant HT might provide relevant indices for developing BM-sparing (BMS) radiotherap...

Background and purpose Scenario-based robust optimization and evaluation is commonly used in proton therapy (PT) with pencil beam scanning (PBS) to ensure adequate dose to the clinical target volume (CTV). However, a statistically accurate assessment of the clinical application of this approach is lacking. In this study, we assess target dose in a...

Purpose or Objective In proton therapy (PT) with pencil beam scanning, scenario-based robust optimization and evaluation are commonly used to ensure adequate dose to the CTV. However, the setup robustness setting (SRS) is often still based on photon margin recipes assuming dose invariance under small shifts, which does not apply to PT. In this stud...

Purpose or Objective In intensity-modulated proton therapy (IMPT), the clinical assessment of robust dose in organs-at-risk (OARs) is equally important as ensuring target dose in the CTV. At our center, clinical robustness evaluations are based on the consensus within the Dutch Proton Therapy (DUPROTON) group. CTV and serial OARs doses are prescrib...

Introduction: With the introduction of accelerated partial breast irradiation (APBI) and the trend of reducing the number of fractions, the geometric accuracy of treatment delivery becomes critical. APBI patient setup is often based on fiducials, as the seroma is frequently not visible on pretreatment imaging. We assessed the motion of fiducials r...

Background and purpose A single-isocenter stereotactic body radiotherapy (SBRT) approach for multiple lung metastases has the potential to lower cumulative patient dose and reduce overall treatment time. However, the magnitude of inter-lesion position variation is currently unknown and not incorporated in margin calculations. The aim of this study...

Purpose: Eye-dedicated proton therapy (PT) facilities are used to treat malignant intraocular lesions, especially uveal melanoma (UM). The first commercial ocular PT beamline from Varian was installed in the Netherlands. In this work, the conceptual design of the new eyeline is presented. A comprehensive comparison against five PT centers with ded...

Purpose: To develop a high-resolution three-dimensional (3D) magnetic resonance imaging (MRI)-based treatment planning approach for uveal melanomas (UM) in proton therapy. Materials/methods: For eight patients with UM, a segmentation of the gross tumor volume (GTV) and organs-at-risk (OARs) was performed on T1- and T2-weighted 7 Tesla MRI image dat...

Purpose To study the trade-offs of three online strategies to adapt treatment plans of patients with Locally Advanced Pancreatic Carcinomas (LAPC) treated on the CyberKnife with tumor tracking. Materials and Methods A total of 35 planning CT and 98 daily in-room CT scans were collected from 35 LAPC patients. Planned dose distributions, optimized w...