Marco Van Vulpen | University Medical Center Utrecht ,The Netherlands (original) (raw)

Papers by Marco Van Vulpen

Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology, 2015

To explore the value of diffusion-weighted magnetic resonance imaging (DW-MRI) for the prediction... more To explore the value of diffusion-weighted magnetic resonance imaging (DW-MRI) for the prediction of pathologic response to neoadjuvant chemoradiotherapy (nCRT) in esophageal cancer. In 20 patients receiving nCRT for esophageal cancer DW-MRI scanning was performed before nCRT, after 8-13 fractions, and before surgery. The median tumor apparent diffusion coefficient (ADC) was determined at these three time points. The predictive potential of initial tumor ADC, and change in ADC (ΔADC) during and after treatment for pathologic complete response (pathCR) and good response were assessed. Good response was defined as pathCR or near-pathCR (tumor regression grade [TRG] 1 or 2). A pathCR after nCRT was found in 4 of 20 patients (20%), and 8 patients (40%) showed a good response to nCRT. The ΔADCduring was significantly higher in pathCR vs. non-pathCR patients (34.6%±10.7% [mean±SD] vs. 14.0%±13.1%, p=0.016), as well as in good vs. poor responders (30.5%±8.3% vs. 9.5%±12.5%, p=0.002). The Δ...

International journal of radiation oncology, biology, physics, 2005

The goal of this planning study was to compare step-and-shoot intensity-modulated radiotherapy (I... more The goal of this planning study was to compare step-and-shoot intensity-modulated radiotherapy (IMRT) plans with helical dynamic IMRT plans for oropharynx patients on the basis of dose distribution. Five patients with oropharynx cancer had been previously treated by step-and-shoot IMRT at the University Medical Centre Utrecht, The Netherlands, applying five fields and approximately 60-90 segments. Inverse planning was carried out using Plato, version 2.6.2. For each patient, an inverse IMRT plan was also made using Tomotherapy Hi-Art System, version 2.0, and using the same targets and optimization goals. Statistical analysis was performed by a paired t test. All tomotherapy plans compared favorably with the step-and-shoot plans regarding sparing of the organs at risk and keeping an equivalent target dose homogeneity. Tomotherapy plans in particular realized sharper dose gradients compared with the step-and-shoot plans. The mean dose to all parotid glands (n = 10) decreased on averag...

Journal of therapeutic ultrasound, 2014

Magnetic resonance-guided high intensity focused ultrasound (MR-HIFU) has recently emerged as an ... more Magnetic resonance-guided high intensity focused ultrasound (MR-HIFU) has recently emerged as an effective treatment option for painful bone metastases. We describe here the first experience with volumetric MR-HIFU for palliative treatment of painful bone metastases and evaluate the technique on three levels: technical feasibility, safety, and initial effectiveness. In this observational cohort study, 11 consecutive patients (7 male and 4 female; median age, 60 years; age range, 53-86 years) underwent 13 treatments for 12 bone metastases. All patients exhibited persistent metastatic bone pain refractory to the standard of care. Patients were asked to rate their worst pain on an 11-point pain scale before treatment, 3 days after treatment, and 1 month after treatment. Complications were monitored. All data were prospectively recorded in the context of routine clinical care. Response was defined as a ≥2-point decrease in pain at the treated site without increase in analgesic intake. B...

Radiotherapy and Oncology, 2014

Multimorbidity and declining performance in elderly cancer patients may result in less treatment ... more Multimorbidity and declining performance in elderly cancer patients may result in less treatment benefit. We investigated whether age is a predictor for pain response and quality of life (QoL) after radiotherapy in patients with painful bone metastases. The database of the Dutch Bone Metastasis Study was used (1996-1999). 1157 patients, irradiated for painful bone metastases, rated their pain, QoL-domains and overall health at baseline and during follow-up. Response was calculated taking into account changes in pain score and medication. Patients were grouped into three age cohorts: A: <65 (n=520), B: 65-74 (n=410) and C: ⩾75years (n=227). No significant difference existed in pain response between cohorts: 78% in cohort A, 74% in B and 67% in C. When assessing baseline QoL, a significant difference in activity level was noticed, with more impairment in elderly compared to younger patients (C versus B (p=0.01), C versus A (p<0.001)). Other QoL-domains were similar at baseline and during follow-up among cohorts. A pain response was significantly associated with improvement of health-related QoL (OR 3.74, 95% CI 2.66-5.25). The majority of elderly patients with painful bone metastases responded to radiotherapy and showed comparable overall QoL compared to their younger counterparts. Age is not a predictor for pain response or QoL.

Radiotherapy and Oncology, 2008

Background and purpose: The purpose of this study is to investigate the feasibility of adequate d... more Background and purpose: The purpose of this study is to investigate the feasibility of adequate dose coverage in permanent prostate brachytherapy using divergent needle insertion methods. These methods can be useful in magnetic resonance imaging (MRI) guided needle insertion techniques to avoid pubic arch interference.

European Urology Supplements, 2009

International Journal of Hyperthermia, 2003

A study was performed on regional hyperthermia for patients with locally advanced prostate carcin... more A study was performed on regional hyperthermia for patients with locally advanced prostate carcinoma. The primary objective was to analyse the thermometry data with an emphasis on the possibility of replacing invasive thermometry by tumour-related intra-luminal thermometry. Fourteen patients were treated with a combination of conformal external beam radiotherapy (70 Gy) and hyperthermia. Hyperthermia was delivered using the Coaxial TEM system, one treatment per week, to a total of five treatments. Thermometry was performed in bladder, urethra, rectum and esophagus. Invasive thermometry in the prostate was carried out during one or two treatments for each patient by placing transperineally a central and a peripheral catheter. Heterogeneous temperature distributions were measured in the prostate. The mean average invasive temperature range was 1.1 degrees C. Due to the temperature heterogeneity and a limited number of thermometry sensors (mean 7, range 2-13), large variability between treatments and patients existed regarding achieved temperatures and dose. The mean invasive T90 was 40.2 +/- 0.6 degrees C and T50 was 40.8 +/- 0.6 degrees C. The mean Cum min T90>40.5 degrees C per treatment was 22 (range 0-50). Importantly, intra-luminal temperatures did not reliably predict invasively measured temperatures. Invasive thermometry, therefore, remains compulsory to calculate a thermal dose for an individual patient. Changes in temperature during treatment, measured by the urethral sensors, corresponded well with changes in temperature measured by the individual invasive sensors. Similar comparison of rectal temperature changes with intra-prostatic temperature changes was not as predictive. The similarity in temperature changes between the urethral and interstial sites, suggests that urethral temperatures are sufficient for treatment optimization. The SAR profile did not correspond with the temperature profile indicating heterogeneous perfusion. Although regional hyperthermia in combination with external beam radiotherapy for locally advanced prostate carcinoma is clinically feasible, the question on the importance of invasive thermometry remains.

International Journal of Hyperthermia, 2003

The aim of this prospective study was to describe quality of life (QoL) in patients with locally ... more The aim of this prospective study was to describe quality of life (QoL) in patients with locally advanced prostate carcinoma treated with conventional radiotherapy and to evaluate the influence of adding regional or interstitial hyperthermia. All patients were irradiated using a CT-planned conventional three field technique, administering 70 Gy to prostate and vesicles. In two different phase I studies, hyperthermia was added to the radiotherapy. Twelve patients were treated with one interstitial hyperthermia treatment, lasting 60 min. Fourteen patients have been treated with five regional hyperthermia treatments, lasting 75 min each. In both hyperthermia studies, the body, bladder and rectum temperatures remained below safety limits. Patients treated with radiotherapy alone (n = 58) or combined with regional (n = 8) or interstitial hyperthermia (n = 12) completed the European Organization for Research and Treatment of Cancer (EORTC) core questionnaire (C30 + 3), the EORTC prostate cancer module (PR25) and the Rand 36 health survey before treatment and 1 and 6 months after completion of treatment. Analysis of Variance (ANOVA) for repeated measurements has been performed to describe the data. All patient groups were comparable concerning patient characteristics. No significant interaction or difference in QoL has been noticed between the two hyperthermia patient groups and the patient group without hyperthermia. Therefore, all groups were analysed together (n = 78) to detect QoL changes in time. A deterioration of QoL has been measured from baseline to 1 month after treatment. Fatigue, pain, urinary symptoms, bowel symptoms and financial difficulties increased significantly. Social, physical and role functioning worsened significantly. No differences in QoL were measured 6 months after treatment compared to the baseline measurement, except for a decrease in sexual activity. After radiotherapy with or without hyperthermia only a temporary deterioration of QoL occurs, concerning social, psychological and disease related symptoms. Additional hyperthermia does not seem to decrease QoL.

Radiotherapy and Oncology, 2006

Radiotherapy and Oncology, 2014

To characterize pancreatic tumor motion and to develop a gating scheme for radiotherapy in pancre... more To characterize pancreatic tumor motion and to develop a gating scheme for radiotherapy in pancreatic cancer. Two cine MRIs of 60s each were performed in fifteen pancreatic cancer patients, one in sagittal direction and one in coronal direction. A Minimum Output Sum of Squared Error (MOSSE) adaptive correlation filter was used to quantify tumor motion in craniocaudal, lateral and anteroposterior directions. To develop a gating scheme, stability of the breathing phases was examined and a gating window assessment was created, incorporating tumor motion, treatment time and motion margins. The largest tumor motion was found in craniocaudal direction, with an average peak-to-peak amplitude of 15mm (range 6-34mm). Amplitude of the tumor in the anteroposterior direction was on average 5mm (range 1-13mm). The least motion was seen in lateral direction (average 3mm, range 2-5mm). The end exhale position was the most stable position in the breathing cycle and tumors spent more time closer to the end exhale position than to the end inhale position. On average, a margin of 25% of the maximum craniocaudal breathing amplitude was needed to achieve full target coverage with a duty cycle of 50%. When reducing the duty cycle to 50%, a margin of 5mm was sufficient to cover the target in 11 out of 15 patients. Gated delivery for radiotherapy of pancreatic cancer is best performed around the end exhale position as this is the most stable position in the breathing cycle. Considerable margin reduction can be established at moderate duty cycles, yielding acceptable treatment efficiency. However, motion patterns and amplitude do substantially differ between individual patients. Therefore, individual treatment strategies should be considered for radiotherapy in pancreatic cancer.

International Journal of Radiation Oncology*Biology*Physics, 2014

includes only Marnofsky performance status and primary tumor, with a reasonable discrimination.

Trials, 2011

The treatment results of external beam radiotherapy for intermediate and high risk prostate cance... more The treatment results of external beam radiotherapy for intermediate and high risk prostate cancer patients are insufficient with five-year biochemical relapse rates of approximately 35%. Several randomized trials have shown that dose escalation to the entire prostate improves biochemical disease free survival. However, further dose escalation to the whole gland is limited due to an unacceptable high risk of acute and late toxicity. Moreover, local recurrences often originate at the location of the macroscopic tumor, so boosting the radiation dose at the macroscopic tumor within the prostate might increase local control. A reduction of distant metastases and improved survival can be expected by reducing local failure. The aim of this study is to investigate the benefit of an ablative microboost to the macroscopic tumor within the prostate in patients treated with external beam radiotherapy for prostate cancer. The FLAME-trial (Focal Lesion Ablative Microboost in prostatE cancer) is ...

International journal of radiation oncology, biology, physics, Jan 13, 2015

To determine the optimum sampling strategy for retrospective reconstruction of 4-dimensional (4D)... more To determine the optimum sampling strategy for retrospective reconstruction of 4-dimensional (4D) MR data for nonrigid motion characterization of tumor and organs at risk for radiation therapy purposes. For optimization, we compared 2 surrogate signals (external respiratory bellows and internal MRI navigators) and 2 MR sampling strategies (Cartesian and radial) in terms of image quality and robustness. Using the optimized protocol, 6 pancreatic cancer patients were scanned to calculate the 4D motion. Region of interest analysis was performed to characterize the respiratory-induced motion of the tumor and organs at risk simultaneously. The MRI navigator was found to be a more reliable surrogate for pancreatic motion than the respiratory bellows signal. Radial sampling is most benign for undersampling artifacts and intraview motion. Motion characterization revealed interorgan and interpatient variation, as well as heterogeneity within the tumor. A robust 4D-MRI method, based on clinic...

Radiotherapy and Oncology, 2008

Purpose/objectives: In radiotherapy the healthy tissue involvement still poses serious dose limit... more Purpose/objectives: In radiotherapy the healthy tissue involvement still poses serious dose limitations. This results in sub-optimal tumour dose and complications. Daily image guided radiotherapy (IGRT) is the key development in radiation oncology to solve this problem. MRI yields superb soft-tissue visualization and provides several imaging modalities for identification of movements, function and physiology. Integrating MRI functionality with an accelerator can make these capacities available for high precision, real time IGRT.

Radiotherapy and Oncology, 2014

Purpose: Whole-gland salvage for recurrent prostate cancer (PCa) shows high failure and toxicity ... more Purpose: Whole-gland salvage for recurrent prostate cancer (PCa) shows high failure and toxicity rates. Early and adequate localization of recurrences enables focal salvage, thereby potentially improving functional outcomes, while maintaining cancer control. Materials and methods: Retrospective analysis yielded 20 focal salvage I125 brachytherapy patients for locally recurrent PCa after primary radiotherapy. Tumor was defined by multiparametric MRI and correspondence with transrectal biopsies. Dose data were obtained intra-operatively. The tumor was prescribed P144 Gy. Toxicity was scored by the Common Terminology Criteria for Adverse Events version 4 (CTCAE-4). Biochemical failure (BF) was defined using the Phoenix criteria (PSA-nadir + 2.0 ng/ml). Quality of life (QoL) was measured by SF-36 Health Survey and European Organization of Research and Treatment of Cancer (EORTC) C30+3 and PR25 questionnaires. Results: With a median follow-up of 36 months (range 10-45), six patients experienced BF, of which three had no initial response. Grade 3 genitourinary (GU) toxicity occurred in one patient (a urethral stricture). The five previously potent patients retained erectile function. QoL remained decreased with regard to urinary symptoms. Conclusion: Focal salvage I125 brachytherapy showed one grade 3 GU toxicity in the 20 treated patients. Biochemical response and QoL were acceptable. 10@umcutrecht.nl (M. Peters), M.maenhout@ umcutrecht.nl (M. Maenhout). Radiotherapy and Oncology xxx (2014) xxx-xxx Contents lists available at ScienceDirect Radiotherapy and Oncology j o u r n a l h o m e p a g e : w w w . t h e g r e e n j o u r n a l . c o m Please cite this article in press as: Peters M et al. Focal salvage iodine-125 brachytherapy for prostate cancer recurrences after primary radiotherapy: A retrospective study regarding toxicity, biochemical outcome and quality of life. Radiother Oncol (2014), http://dx.

Radiotherapy and Oncology, 2011

S 295 breast was 3.3% (range 1.5-6.1) in supine and 6% (range 2-12.8) in prone position. Conclusi... more S 295 breast was 3.3% (range 1.5-6.1) in supine and 6% (range 2-12.8) in prone position. Conclusions: Our experience shows that prone position could decrease lung doses but for CTV, heart and controlateral breast dosimetric data are more favorable in the supine than in prone position. Only 3 patients received the actual treatment in the prone position due to patients compliance, their particular anatomical configuration or clear superiority of the treatment plan. 745 poster BREAST CONSERVING THERAPY: EVALUATION OF THE TUMOR DIAMETER AND TREATED VOLUMES

Practical Radiation Oncology, 2014

While the importance of a consistent rectal volume during radiation therapy planning and treatmen... more While the importance of a consistent rectal volume during radiation therapy planning and treatment for patients receiving radiation therapy to the prostate is recognized, there is no clear guidance as to the most effective method. This review examines the evidence for the efficacy of rectal preparations. Eighteen papers were found where the primary aim was to investigate a rectal emptying intervention and included 5 different strategies. These included evacuation techniques, dietary interventions, laxatives, and enemas and were either investigated alone or in combination. There is no robust evidence to recommend one rectal emptying strategy over another. Further investigation in adequately powered clinical trials is advised.

Radiotherapy and Oncology, 2011

Seminars in Radiation Oncology, 2014

The current image-guided radiotherapy systems are suboptimal in the esophagus, pancreas, kidney, ... more The current image-guided radiotherapy systems are suboptimal in the esophagus, pancreas, kidney, rectum, lymph node, etc. These locations in the body are not easily accessible for fiducials and cannot be visualized sufficiently on cone-beam computed tomographies, making daily patient set-up prone to geometrical uncertainties and hinder dose optimization. Additional interfraction and intrafraction uncertainties for those locations arise from motion with breathing and organ filling. To allow real-time imaging of all patient tumor locations at the actual treatment position a fully integrated 1.5-T, diagnostic quality, magnetic resonance imaging with a 6-MV linear accelerator is presented. This system must enable detailed dose painting at all body locations.

Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology, 2015

To explore the value of diffusion-weighted magnetic resonance imaging (DW-MRI) for the prediction... more To explore the value of diffusion-weighted magnetic resonance imaging (DW-MRI) for the prediction of pathologic response to neoadjuvant chemoradiotherapy (nCRT) in esophageal cancer. In 20 patients receiving nCRT for esophageal cancer DW-MRI scanning was performed before nCRT, after 8-13 fractions, and before surgery. The median tumor apparent diffusion coefficient (ADC) was determined at these three time points. The predictive potential of initial tumor ADC, and change in ADC (ΔADC) during and after treatment for pathologic complete response (pathCR) and good response were assessed. Good response was defined as pathCR or near-pathCR (tumor regression grade [TRG] 1 or 2). A pathCR after nCRT was found in 4 of 20 patients (20%), and 8 patients (40%) showed a good response to nCRT. The ΔADCduring was significantly higher in pathCR vs. non-pathCR patients (34.6%±10.7% [mean±SD] vs. 14.0%±13.1%, p=0.016), as well as in good vs. poor responders (30.5%±8.3% vs. 9.5%±12.5%, p=0.002). The Δ...

International journal of radiation oncology, biology, physics, 2005

The goal of this planning study was to compare step-and-shoot intensity-modulated radiotherapy (I... more The goal of this planning study was to compare step-and-shoot intensity-modulated radiotherapy (IMRT) plans with helical dynamic IMRT plans for oropharynx patients on the basis of dose distribution. Five patients with oropharynx cancer had been previously treated by step-and-shoot IMRT at the University Medical Centre Utrecht, The Netherlands, applying five fields and approximately 60-90 segments. Inverse planning was carried out using Plato, version 2.6.2. For each patient, an inverse IMRT plan was also made using Tomotherapy Hi-Art System, version 2.0, and using the same targets and optimization goals. Statistical analysis was performed by a paired t test. All tomotherapy plans compared favorably with the step-and-shoot plans regarding sparing of the organs at risk and keeping an equivalent target dose homogeneity. Tomotherapy plans in particular realized sharper dose gradients compared with the step-and-shoot plans. The mean dose to all parotid glands (n = 10) decreased on averag...

Journal of therapeutic ultrasound, 2014

Magnetic resonance-guided high intensity focused ultrasound (MR-HIFU) has recently emerged as an ... more Magnetic resonance-guided high intensity focused ultrasound (MR-HIFU) has recently emerged as an effective treatment option for painful bone metastases. We describe here the first experience with volumetric MR-HIFU for palliative treatment of painful bone metastases and evaluate the technique on three levels: technical feasibility, safety, and initial effectiveness. In this observational cohort study, 11 consecutive patients (7 male and 4 female; median age, 60 years; age range, 53-86 years) underwent 13 treatments for 12 bone metastases. All patients exhibited persistent metastatic bone pain refractory to the standard of care. Patients were asked to rate their worst pain on an 11-point pain scale before treatment, 3 days after treatment, and 1 month after treatment. Complications were monitored. All data were prospectively recorded in the context of routine clinical care. Response was defined as a ≥2-point decrease in pain at the treated site without increase in analgesic intake. B...

Radiotherapy and Oncology, 2014

Multimorbidity and declining performance in elderly cancer patients may result in less treatment ... more Multimorbidity and declining performance in elderly cancer patients may result in less treatment benefit. We investigated whether age is a predictor for pain response and quality of life (QoL) after radiotherapy in patients with painful bone metastases. The database of the Dutch Bone Metastasis Study was used (1996-1999). 1157 patients, irradiated for painful bone metastases, rated their pain, QoL-domains and overall health at baseline and during follow-up. Response was calculated taking into account changes in pain score and medication. Patients were grouped into three age cohorts: A: <65 (n=520), B: 65-74 (n=410) and C: ⩾75years (n=227). No significant difference existed in pain response between cohorts: 78% in cohort A, 74% in B and 67% in C. When assessing baseline QoL, a significant difference in activity level was noticed, with more impairment in elderly compared to younger patients (C versus B (p=0.01), C versus A (p<0.001)). Other QoL-domains were similar at baseline and during follow-up among cohorts. A pain response was significantly associated with improvement of health-related QoL (OR 3.74, 95% CI 2.66-5.25). The majority of elderly patients with painful bone metastases responded to radiotherapy and showed comparable overall QoL compared to their younger counterparts. Age is not a predictor for pain response or QoL.

Radiotherapy and Oncology, 2008

Background and purpose: The purpose of this study is to investigate the feasibility of adequate d... more Background and purpose: The purpose of this study is to investigate the feasibility of adequate dose coverage in permanent prostate brachytherapy using divergent needle insertion methods. These methods can be useful in magnetic resonance imaging (MRI) guided needle insertion techniques to avoid pubic arch interference.

European Urology Supplements, 2009

International Journal of Hyperthermia, 2003

A study was performed on regional hyperthermia for patients with locally advanced prostate carcin... more A study was performed on regional hyperthermia for patients with locally advanced prostate carcinoma. The primary objective was to analyse the thermometry data with an emphasis on the possibility of replacing invasive thermometry by tumour-related intra-luminal thermometry. Fourteen patients were treated with a combination of conformal external beam radiotherapy (70 Gy) and hyperthermia. Hyperthermia was delivered using the Coaxial TEM system, one treatment per week, to a total of five treatments. Thermometry was performed in bladder, urethra, rectum and esophagus. Invasive thermometry in the prostate was carried out during one or two treatments for each patient by placing transperineally a central and a peripheral catheter. Heterogeneous temperature distributions were measured in the prostate. The mean average invasive temperature range was 1.1 degrees C. Due to the temperature heterogeneity and a limited number of thermometry sensors (mean 7, range 2-13), large variability between treatments and patients existed regarding achieved temperatures and dose. The mean invasive T90 was 40.2 +/- 0.6 degrees C and T50 was 40.8 +/- 0.6 degrees C. The mean Cum min T90>40.5 degrees C per treatment was 22 (range 0-50). Importantly, intra-luminal temperatures did not reliably predict invasively measured temperatures. Invasive thermometry, therefore, remains compulsory to calculate a thermal dose for an individual patient. Changes in temperature during treatment, measured by the urethral sensors, corresponded well with changes in temperature measured by the individual invasive sensors. Similar comparison of rectal temperature changes with intra-prostatic temperature changes was not as predictive. The similarity in temperature changes between the urethral and interstial sites, suggests that urethral temperatures are sufficient for treatment optimization. The SAR profile did not correspond with the temperature profile indicating heterogeneous perfusion. Although regional hyperthermia in combination with external beam radiotherapy for locally advanced prostate carcinoma is clinically feasible, the question on the importance of invasive thermometry remains.

International Journal of Hyperthermia, 2003

The aim of this prospective study was to describe quality of life (QoL) in patients with locally ... more The aim of this prospective study was to describe quality of life (QoL) in patients with locally advanced prostate carcinoma treated with conventional radiotherapy and to evaluate the influence of adding regional or interstitial hyperthermia. All patients were irradiated using a CT-planned conventional three field technique, administering 70 Gy to prostate and vesicles. In two different phase I studies, hyperthermia was added to the radiotherapy. Twelve patients were treated with one interstitial hyperthermia treatment, lasting 60 min. Fourteen patients have been treated with five regional hyperthermia treatments, lasting 75 min each. In both hyperthermia studies, the body, bladder and rectum temperatures remained below safety limits. Patients treated with radiotherapy alone (n = 58) or combined with regional (n = 8) or interstitial hyperthermia (n = 12) completed the European Organization for Research and Treatment of Cancer (EORTC) core questionnaire (C30 + 3), the EORTC prostate cancer module (PR25) and the Rand 36 health survey before treatment and 1 and 6 months after completion of treatment. Analysis of Variance (ANOVA) for repeated measurements has been performed to describe the data. All patient groups were comparable concerning patient characteristics. No significant interaction or difference in QoL has been noticed between the two hyperthermia patient groups and the patient group without hyperthermia. Therefore, all groups were analysed together (n = 78) to detect QoL changes in time. A deterioration of QoL has been measured from baseline to 1 month after treatment. Fatigue, pain, urinary symptoms, bowel symptoms and financial difficulties increased significantly. Social, physical and role functioning worsened significantly. No differences in QoL were measured 6 months after treatment compared to the baseline measurement, except for a decrease in sexual activity. After radiotherapy with or without hyperthermia only a temporary deterioration of QoL occurs, concerning social, psychological and disease related symptoms. Additional hyperthermia does not seem to decrease QoL.

Radiotherapy and Oncology, 2006

Radiotherapy and Oncology, 2014

To characterize pancreatic tumor motion and to develop a gating scheme for radiotherapy in pancre... more To characterize pancreatic tumor motion and to develop a gating scheme for radiotherapy in pancreatic cancer. Two cine MRIs of 60s each were performed in fifteen pancreatic cancer patients, one in sagittal direction and one in coronal direction. A Minimum Output Sum of Squared Error (MOSSE) adaptive correlation filter was used to quantify tumor motion in craniocaudal, lateral and anteroposterior directions. To develop a gating scheme, stability of the breathing phases was examined and a gating window assessment was created, incorporating tumor motion, treatment time and motion margins. The largest tumor motion was found in craniocaudal direction, with an average peak-to-peak amplitude of 15mm (range 6-34mm). Amplitude of the tumor in the anteroposterior direction was on average 5mm (range 1-13mm). The least motion was seen in lateral direction (average 3mm, range 2-5mm). The end exhale position was the most stable position in the breathing cycle and tumors spent more time closer to the end exhale position than to the end inhale position. On average, a margin of 25% of the maximum craniocaudal breathing amplitude was needed to achieve full target coverage with a duty cycle of 50%. When reducing the duty cycle to 50%, a margin of 5mm was sufficient to cover the target in 11 out of 15 patients. Gated delivery for radiotherapy of pancreatic cancer is best performed around the end exhale position as this is the most stable position in the breathing cycle. Considerable margin reduction can be established at moderate duty cycles, yielding acceptable treatment efficiency. However, motion patterns and amplitude do substantially differ between individual patients. Therefore, individual treatment strategies should be considered for radiotherapy in pancreatic cancer.

International Journal of Radiation Oncology*Biology*Physics, 2014

includes only Marnofsky performance status and primary tumor, with a reasonable discrimination.

Trials, 2011

The treatment results of external beam radiotherapy for intermediate and high risk prostate cance... more The treatment results of external beam radiotherapy for intermediate and high risk prostate cancer patients are insufficient with five-year biochemical relapse rates of approximately 35%. Several randomized trials have shown that dose escalation to the entire prostate improves biochemical disease free survival. However, further dose escalation to the whole gland is limited due to an unacceptable high risk of acute and late toxicity. Moreover, local recurrences often originate at the location of the macroscopic tumor, so boosting the radiation dose at the macroscopic tumor within the prostate might increase local control. A reduction of distant metastases and improved survival can be expected by reducing local failure. The aim of this study is to investigate the benefit of an ablative microboost to the macroscopic tumor within the prostate in patients treated with external beam radiotherapy for prostate cancer. The FLAME-trial (Focal Lesion Ablative Microboost in prostatE cancer) is ...

International journal of radiation oncology, biology, physics, Jan 13, 2015

To determine the optimum sampling strategy for retrospective reconstruction of 4-dimensional (4D)... more To determine the optimum sampling strategy for retrospective reconstruction of 4-dimensional (4D) MR data for nonrigid motion characterization of tumor and organs at risk for radiation therapy purposes. For optimization, we compared 2 surrogate signals (external respiratory bellows and internal MRI navigators) and 2 MR sampling strategies (Cartesian and radial) in terms of image quality and robustness. Using the optimized protocol, 6 pancreatic cancer patients were scanned to calculate the 4D motion. Region of interest analysis was performed to characterize the respiratory-induced motion of the tumor and organs at risk simultaneously. The MRI navigator was found to be a more reliable surrogate for pancreatic motion than the respiratory bellows signal. Radial sampling is most benign for undersampling artifacts and intraview motion. Motion characterization revealed interorgan and interpatient variation, as well as heterogeneity within the tumor. A robust 4D-MRI method, based on clinic...

Radiotherapy and Oncology, 2008

Purpose/objectives: In radiotherapy the healthy tissue involvement still poses serious dose limit... more Purpose/objectives: In radiotherapy the healthy tissue involvement still poses serious dose limitations. This results in sub-optimal tumour dose and complications. Daily image guided radiotherapy (IGRT) is the key development in radiation oncology to solve this problem. MRI yields superb soft-tissue visualization and provides several imaging modalities for identification of movements, function and physiology. Integrating MRI functionality with an accelerator can make these capacities available for high precision, real time IGRT.

Radiotherapy and Oncology, 2014

Purpose: Whole-gland salvage for recurrent prostate cancer (PCa) shows high failure and toxicity ... more Purpose: Whole-gland salvage for recurrent prostate cancer (PCa) shows high failure and toxicity rates. Early and adequate localization of recurrences enables focal salvage, thereby potentially improving functional outcomes, while maintaining cancer control. Materials and methods: Retrospective analysis yielded 20 focal salvage I125 brachytherapy patients for locally recurrent PCa after primary radiotherapy. Tumor was defined by multiparametric MRI and correspondence with transrectal biopsies. Dose data were obtained intra-operatively. The tumor was prescribed P144 Gy. Toxicity was scored by the Common Terminology Criteria for Adverse Events version 4 (CTCAE-4). Biochemical failure (BF) was defined using the Phoenix criteria (PSA-nadir + 2.0 ng/ml). Quality of life (QoL) was measured by SF-36 Health Survey and European Organization of Research and Treatment of Cancer (EORTC) C30+3 and PR25 questionnaires. Results: With a median follow-up of 36 months (range 10-45), six patients experienced BF, of which three had no initial response. Grade 3 genitourinary (GU) toxicity occurred in one patient (a urethral stricture). The five previously potent patients retained erectile function. QoL remained decreased with regard to urinary symptoms. Conclusion: Focal salvage I125 brachytherapy showed one grade 3 GU toxicity in the 20 treated patients. Biochemical response and QoL were acceptable. 10@umcutrecht.nl (M. Peters), M.maenhout@ umcutrecht.nl (M. Maenhout). Radiotherapy and Oncology xxx (2014) xxx-xxx Contents lists available at ScienceDirect Radiotherapy and Oncology j o u r n a l h o m e p a g e : w w w . t h e g r e e n j o u r n a l . c o m Please cite this article in press as: Peters M et al. Focal salvage iodine-125 brachytherapy for prostate cancer recurrences after primary radiotherapy: A retrospective study regarding toxicity, biochemical outcome and quality of life. Radiother Oncol (2014), http://dx.

Radiotherapy and Oncology, 2011

S 295 breast was 3.3% (range 1.5-6.1) in supine and 6% (range 2-12.8) in prone position. Conclusi... more S 295 breast was 3.3% (range 1.5-6.1) in supine and 6% (range 2-12.8) in prone position. Conclusions: Our experience shows that prone position could decrease lung doses but for CTV, heart and controlateral breast dosimetric data are more favorable in the supine than in prone position. Only 3 patients received the actual treatment in the prone position due to patients compliance, their particular anatomical configuration or clear superiority of the treatment plan. 745 poster BREAST CONSERVING THERAPY: EVALUATION OF THE TUMOR DIAMETER AND TREATED VOLUMES

Practical Radiation Oncology, 2014

While the importance of a consistent rectal volume during radiation therapy planning and treatmen... more While the importance of a consistent rectal volume during radiation therapy planning and treatment for patients receiving radiation therapy to the prostate is recognized, there is no clear guidance as to the most effective method. This review examines the evidence for the efficacy of rectal preparations. Eighteen papers were found where the primary aim was to investigate a rectal emptying intervention and included 5 different strategies. These included evacuation techniques, dietary interventions, laxatives, and enemas and were either investigated alone or in combination. There is no robust evidence to recommend one rectal emptying strategy over another. Further investigation in adequately powered clinical trials is advised.

Radiotherapy and Oncology, 2011

Seminars in Radiation Oncology, 2014

The current image-guided radiotherapy systems are suboptimal in the esophagus, pancreas, kidney, ... more The current image-guided radiotherapy systems are suboptimal in the esophagus, pancreas, kidney, rectum, lymph node, etc. These locations in the body are not easily accessible for fiducials and cannot be visualized sufficiently on cone-beam computed tomographies, making daily patient set-up prone to geometrical uncertainties and hinder dose optimization. Additional interfraction and intrafraction uncertainties for those locations arise from motion with breathing and organ filling. To allow real-time imaging of all patient tumor locations at the actual treatment position a fully integrated 1.5-T, diagnostic quality, magnetic resonance imaging with a 6-MV linear accelerator is presented. This system must enable detailed dose painting at all body locations.