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Featured researches published by W. Peter Vandertop.


Lancet Neurology | 2009

Cognitive and radiological effects of radiotherapy in patients with low-grade glioma : long-term follow-up

Linda Douw; Martin Klein; Selene Saa Fagel; Josje van den Heuvel; Martin J. B. Taphoorn; Neil K. Aaronson; Tjeerd J. Postma; W. Peter Vandertop; Jacob J Mooij; Rudolf H. Boerman; G.N. Beute; J.D. Sluimer; Ben J. Slotman; Jaap C. Reijneveld; Jan J. Heimans

BACKGROUND Our previous study on cognitive functioning among 195 patients with low-grade glioma (LGG) a mean of 6 years after diagnosis suggested that the tumour itself, rather than the radiotherapy used to treat it, has the most deleterious effect on cognitive functioning; only high fraction dose radiotherapy (>2 Gy) resulted in significant added cognitive deterioration. The present study assesses the radiological and cognitive abnormalities in survivors of LGG at a mean of 12 years after first diagnosis. METHODS Patients who have had stable disease since the first assessment were invited for follow-up cognitive assessment (letter-digit substitution test, concept shifting test, Stroop colour-word test, visual verbal learning test, memory comparison test, and categoric word fluency). Compound scores in six cognitive domains (attention, executive functioning, verbal memory, working memory, psychomotor functioning, and information processing speed) were calculated to detect differences between patients who had radiotherapy and patients who did not have radiotherapy. White-matter hyperintensities and global cortical atrophy were rated on MRI scans. FINDINGS 65 patients completed neuropsychological follow-up at a mean of 12 years (range 6-28 years). 32 (49%) patients had received radiotherapy (three had fraction doses >2 Gy). The patients who had radiotherapy had more deficits that affected attentional functioning at the second follow-up, regardless of fraction dose, than those who did not have radiotherapy (-1.6 [SD 2.4] vs -0.1 [1.3], p=0.003; mean difference 1.4, 95% CI 0.5-2.4). The patients who had radiotherapy also did worse in measures of executive functioning (-2.0 [3.7] vs -0.5 [1.2], p=0.03; mean difference 1.5, 0.2-2.9) and information processing speed (-2.0 [3.7] vs -0.6 [1.5], p=0.05; mean difference 0.8, 0.009-1.6]) between the two assessments. Furthermore, attentional functioning deteriorated significantly between the first and second assessments in patients who had radiotherapy (p=0.25). In total, 17 (53%) patients who had radiotherapy developed cognitive disabilities deficits in at least five of 18 neuropsychological test parameters compared with four (27%) patients who were radiotherapy naive. White-matter hyperintensities and global cortical atrophy were associated with worse cognitive functioning in several domains. INTERPRETATION Long-term survivors of LGG who did not have radiotherapy had stable radiological and cognitive status. By contrast, patients with low-grade glioma who received radiotherapy showed a progressive decline in attentional functioning, even those who received fraction doses that are regarded as safe (</=2 Gy). These cognitive deficits are associated with radiological abnormalities. Our results suggest that the risk of long-term cognitive and radiological compromise that is associated with radiotherapy should be considered when treatment is planned. FUNDING Kaptein Fonds; Schering Plough.


Annals of Neurology | 2003

Epilepsy in low-grade gliomas: the impact on cognitive function and quality of life.

Martin Klein; Nadine H. J. Engelberts; Henk M. van der Ploeg; Dorothée Kasteleijn-Nolst Trenité; Neil K. Aaronson; Martin J. B. Taphoorn; Hans Baaijen; W. Peter Vandertop; Martin J. Muller; Tjeerd J. Postma; Jan J. Heimans

Low‐grade gliomas frequently are associated with epilepsy. The purpose of this study is to determine the impact of epilepsy and antiepileptic drug (AED) treatment on cognitive functioning and health‐related quality of life (HRQOL) in these patients. One hundred fifty‐six patients without clinical or radiological signs of tumor recurrence for at least 1 year after histological diagnosis and with an epilepsy burden (based on seizure frequency and AED use) ranging from none to severe were compared with healthy controls. The association between epilepsy burden and cognition/HRQOL was also investigated. Eighty‐six percent of the patients had epilepsy and 50% of those using AEDs actually were seizure‐free. Compared with healthy controls, glioma patients had significant reductions in information processing speed, psychomotor function, attentional functioning, verbal and working memory, executive functioning, and HRQOL. The increase in epilepsy burden that was associated with significant reductions in all cognitive domains except for attentional and memory functioning could primarily be attributed to the use of AEDs, whereas the decline in HRQOL could be ascribed to the lack of complete seizure control. In conclusion, low‐grade glioma patients suffer from a number of neuropsychological and psychological problems that are aggravated by the severity of epilepsy and by the intensity of the treatment.


JAMA | 2011

Treatment of Brain Arteriovenous Malformations: A Systematic Review and Meta-analysis

Janneke van Beijnum; H. Bart van der Worp; Dennis R. Buis; Rustam Al-Shahi Salman; L. Jaap Kappelle; Gabriel J.E. Rinkel; Jan Willem Berkelbach van der Sprenkel; W. Peter Vandertop; Ale Algra; Catharina J.M. Klijn

CONTEXT Outcomes following treatment of brain arteriovenous malformations (AVMs) with microsurgery, embolization, stereotactic radiosurgery (SRS), or combinations vary greatly between studies. OBJECTIVES To assess rates of case fatality, long-term risk of hemorrhage, complications, and successful obliteration of brain AVMs after interventional treatment and to assess determinants of these outcomes. DATA SOURCES We searched PubMed and EMBASE to March 1, 2011, and hand-searched 6 journals from January 2000 until March 2011. STUDY SELECTION AND DATA EXTRACTION We identified studies fulfilling predefined inclusion criteria. We used Poisson regression analyses to explore associations of patient and study characteristics with case fatality, complications, long-term risk of hemorrhage, and successful brain AVM obliteration. DATA SYNTHESIS We identified 137 observational studies including 142 cohorts, totaling 13,698 patients and 46,314 patient-years of follow-up. Case fatality was 0.68 (95% CI, 0.61-0.76) per 100 person-years overall, 1.1 (95% CI, 0.87-1.3; n = 2549) after microsurgery, 0.50 (95% CI, 0.43-0.58; n = 9436) after SRS, and 0.96 (95% CI, 0.67-1.4; n = 1019) after embolization. Intracranial hemorrhage rates were 1.4 (95% CI, 1.3-1.5) per 100 person-years overall, 0.18 (95% CI, 0.10-0.30) after microsurgery, 1.7 (95% CI, 1.5-1.8) after SRS, and 1.7 (95% CI, 1.3-2.3) after embolization. More recent studies were associated with lower case-fatality rates (rate ratio [RR], 0.972; 95% CI, 0.955-0.989) but increased rates of hemorrhage (RR, 1.02; 95% CI, 1.00-1.03). Male sex (RR, 0.964; 95% CI, 0.945-0.984), small brain AVMs (RR, 0.988; 95% CI, 0.981-0.995), and those with strictly deep venous drainage (RR, 0.975; 95% CI, 0.960-0.990) were associated with lower case fatality. Lower hemorrhage rates were associated with male sex (RR, 0.976, 95% CI, 0.964-0.988), small brain AVMs (RR, 0.988, 95% CI, 0.980-0.996), and brain AVMs with deep venous drainage (0.982, 95% CI, 0.969-0.996). Complications leading to permanent neurological deficits or death occurred in a median 7.4% (range, 0%-40%) of patients after microsurgery, 5.1% (range, 0%-21%) after SRS, and 6.6% (range, 0%-28%) after embolization. Successful brain AVM obliteration was achieved in 96% (range, 0%-100%) of patients after microsurgery, 38% (range, 0%-75%) after SRS, and 13% (range, 0%-94%) after embolization. CONCLUSIONS Although case fatality after treatment has decreased over time, treatment of brain AVM remains associated with considerable risks and incomplete efficacy. Randomized controlled trials comparing different treatment modalities appear justified.


Journal of Clinical Oncology | 2001

Neurobehavioral Status and Health-Related Quality of Life in Newly Diagnosed High-Grade Glioma Patients

Martin Klein; Martin J. B. Taphoorn; Jan J. Heimans; Henk M. van der Ploeg; W. Peter Vandertop; Egbert F. Smit; Sieger Leenstra; Cees A. F. Tulleken; Willem Boogerd; J. Belderbos; Wilmy Cleijne; Neil K. Aaronson

PURPOSE To evaluate the health-related quality of life (HRQOL) and cognitive functioning of high-grade glioma patients in the postneurosurgical period. PATIENTS AND METHODS The HRQOL, as assessed by the Short-Form Health Survey-36, tumor-specific symptoms, and objective and subjective neuropsychologic functioning, of 68 newly diagnosed glioma patients were compared with that of 50 patients with non-small-cell lung cancer (NSCLC) and to age- and sex-matched healthy controls. The association between tumor lateralization, extent of resection, and use of medication, and the HRQOL outcomes was also investigated. RESULTS The HRQOL of the two patient groups was similar but significantly lower than that of the healthy controls. Glioma patients reported significantly more neurologic symptoms and poorer objective and subjective neuropsychologic functioning than the NSCLC patients. Using healthy controls as the reference group, cognitive impairment assessed at the individual patient level was observed in all glioma patients and 52% of the NSCLC patients. Poor performance on timed tasks in the glioma group could be attributed, in large part, to visual and motor deficits. Tumor lateralization was found to affect neuropsychologic functioning in a predictable manner. The extent of resection was not related significantly to neuropsychologic functioning. Corticosteroid use was associated with better recognition memory, whereas antiepileptic drug use was correlated negatively with working memory capacity. CONCLUSION The general HRQOL of glioma patients is similar to that of patients with NSCLC. However, they suffer from a number of condition-specific neurologic and neuropsychologic problems that have a significant impact on their daily lives in the postsurgical period, before treatment with radiotherapy.


Cancer Cell | 2010

In Silico Analysis of Kinase Expression Identifies WEE1 as a Gatekeeper against Mitotic Catastrophe in Glioblastoma

Shahryar E. Mir; Philip C. De Witt Hamer; Przemek M. Krawczyk; Leonora Balaj; An Claes; Johanna M. Niers; Angela A.G. van Tilborg; Aeilko H. Zwinderman; Dirk Geerts; Gertjan J. L. Kaspers; W. Peter Vandertop; Jacqueline Cloos; Bakhos A. Tannous; Pieter Wesseling; Jacob A. Aten; David P. Noske; Cornelis J. F. Van Noorden; Thomas Wurdinger

Kinases execute pivotal cellular functions and are therefore widely investigated as potential targets in anticancer treatment. Here we analyze the kinase gene expression profiles of various tumor types and reveal the wee1 kinase to be overexpressed in glioblastomas. We demonstrate that WEE1 is a major regulator of the G(2) checkpoint in glioblastoma cells. Inhibition of WEE1 by siRNA or small molecular compound in cells exposed to DNA damaging agents results in abrogation of the G(2) arrest, premature termination of DNA repair, and cell death. Importantly, we show that the small-molecule inhibitor of WEE1 sensitizes glioblastoma to ionizing radiation in vivo. Our results suggest that inhibition of WEE1 kinase holds potential as a therapeutic approach in treatment of glioblastoma.


The Lancet | 2012

Magnesium for aneurysmal subarachnoid haemorrhage (MASH-2): a randomised placebo-controlled trial

Sanne M. Dorhout Mees; Ale Algra; W. Peter Vandertop; Fop van Kooten; Hans A. J. M. Kuijsten; Jelis Boiten; Robert J. van Oostenbrugge; Rustam Al-Shahi Salman; Pablo M. Lavados; Gabriel J.E. Rinkel; Walter M. van den Bergh

Summary Background Magnesium sulphate is a neuroprotective agent that might improve outcome after aneurysmal subarachnoid haemorrhage by reducing the occurrence or improving the outcome of delayed cerebral ischaemia. We did a trial to test whether magnesium therapy improves outcome after aneurysmal subarachnoid haemorrhage. Methods We did this phase 3 randomised, placebo-controlled trial in eight centres in Europe and South America. We randomly assigned (with computer-generated random numbers, with permuted blocks of four, stratified by centre) patients aged 18 years or older with an aneurysmal pattern of subarachnoid haemorrhage on brain imaging who were admitted to hospital within 4 days of haemorrhage, to receive intravenous magnesium sulphate, 64 mmol/day, or placebo. We excluded patients with renal failure or bodyweight lower than 50 kg. Patients, treating physicians, and investigators assessing outcomes and analysing data were masked to the allocation. The primary outcome was poor outcome—defined as a score of 4–5 on the modified Rankin Scale—3 months after subarachnoid haemorrhage, or death. We analysed results by intention to treat. We also updated a previous meta-analysis of trials of magnesium treatment for aneurysmal subarachnoid haemorrhage. This study is registered with controlled-trials.com (ISRCTN 68742385) and the EU Clinical Trials Register (EudraCT 2006-003523-36). Findings 1204 patients were enrolled, one of whom had his treatment allocation lost. 606 patients were assigned to the magnesium group (two lost to follow-up), 597 to the placebo (one lost to follow-up). 158 patients (26·2%) had poor outcome in the magnesium group compared with 151 (25·3%) in the placebo group (risk ratio [RR] 1·03, 95% CI 0·85–1·25). Our updated meta-analysis of seven randomised trials involving 2047 patients shows that magnesium is not superior to placebo for reduction of poor outcome after aneurysmal subarachnoid haemorrhage (RR 0·96, 95% CI 0·86–1·08). Interpretation Intravenous magnesium sulphate does not improve clinical outcome after aneurysmal subarachnoid haemorrhage, therefore routine administration of magnesium cannot be recommended. Funding Netherlands Heart Foundation, UK Medical Research Council.


PLOS ONE | 2009

Long-Term Effects of Temporal Lobe Epilepsy on Local Neural Networks: A Graph Theoretical Analysis of Corticography Recordings

Edwin van Dellen; Linda Douw; Johannes C. Baayen; Jan J. Heimans; Sophie C. Ponten; W. Peter Vandertop; Demetrios N. Velis; Cornelis J. Stam; Jaap C. Reijneveld

Purpose Pharmaco-resistant temporal lobe epilepsy (TLE) is often treated with surgical intervention at some point. As epilepsy surgery is considered a last resort by most physicians, a long history of epileptic seizures prior to surgery is not uncommon. Little is known about the effects of ongoing TLE on neural functioning. A better understanding of these effects might influence the moment of surgical intervention. Functional connectivity (interaction between spatially distributed brain areas) and network structure (integration and segregation of information processing) are thought to be essential for optimal brain functioning. We report on the impact of TLE duration on temporal lobe functional connectivity and network characteristics. Methods Functional connectivity of the temporal lobe at the time of surgery was assessed by means of interictal electrocorticography (ECoG) recordings of 27 TLE patients by using the phase lag index (PLI). Graphs (abstract network representations) were reconstructed from the PLI matrix and characterized by the clustering coefficient C (local clustering), the path length L (overall network interconnectedness), and the “small world index” S (network configuration). Results Functional connectivity (average PLI), clustering coefficients, and the small world index were negatively correlated with TLE duration in the broad frequency band (0.5–48 Hz). Discussion Temporal lobe functional connectivity is lower in patients with longer TLE history, and longer TLE duration is correlated with more random network configuration. Our findings suggest that the neural networks of TLE patients become more pathological over time, possibly due to temporal lobe changes associated with long-standing lesional epilepsy.


Blood | 2011

Blood platelets contain tumor-derived RNA biomarkers

R. Jonas A. Nilsson; Leonora Balaj; Esther Hulleman; Sjoerd van Rijn; D. Michiel Pegtel; Maudy Walraven; Anders Widmark; Winald R. Gerritsen; Henk M.W. Verheul; W. Peter Vandertop; David P. Noske; Johan Skog; Thomas Wurdinger

Diagnostic platforms providing biomarkers that are highly predictive for diagnosing, monitoring, and stratifying cancer patients are key instruments in the development of personalized medicine. We demonstrate that tumor cells transfer (mutant) RNA into blood platelets in vitro and in vivo, and show that blood platelets isolated from glioma and prostate cancer patients contain the cancer-associated RNA biomarkers EGFRvIII and PCA3, respectively. In addition, gene-expression profiling revealed a distinct RNA signature in platelets from glioma patients compared with normal control subjects. Because platelets are easily accessible and isolated, they may form an attractive platform for the companion diagnostics of cancer.


Neuro-oncology | 2007

The course of neurocognitive functioning in high-grade glioma patients

Ingeborg Bosma; Maaike J. Vos; Jan J. Heimans; Martin J. B. Taphoorn; Neil K. Aaronson; Tjeerd J. Postma; Henk M. van der Ploeg; Martin J. Muller; W. Peter Vandertop; Ben J. Slotman; Martin Klein

We evaluated the course of neurocognitive functioning in newly diagnosed high-grade glioma patients and specifically the effect of tumor recurrence. Following baseline assessment (after surgery and before radiotherapy), neurocognitive functioning was evaluated at 8 and 16 months. Neurocognitive summary measures were calculated to detect possible deficits in the domains of (1) information processing, (2) psychomotor function, (3) attention, (4) verbal memory, (5) working memory, and (6) executive functioning. Repeated-measures analyses of covariance were used to evaluate changes over time. Thirty-six patients were tested at baseline only. Follow-up data were obtained for 32 patients: 14 had a follow-up at 8 months, and 18 had an additional follow-up at 16 months. Between baseline and eight months, patients deteriorated in information-processing capacity, psychomotor speed, and attentional functioning. Further deterioration was observed between 8 and 16 months. Of 32 patients, 15 suffered from tumor recurrence before the eight-month follow-up. Compared with recurrence-free patients, not only did patients with recurrence have lower information-processing capacity, psychomotor speed, and executive functioning, but they also exhibited a more pronounced deterioration between baseline and eight-month follow-up. This difference could be attributed to the use of antiepileptic drugs in the patient group with recurrence. This study showed a marked decline in neurocognitive functioning in HGG patients in the course of their disease. Patients with tumor progression performed worse on neurocognitive tests than did patients without progression, which could be attributed to the use of antiepileptic drugs. The possibility of deleterious effects is important to consider when prescribing antiepileptic drug treatment.


Neuro-oncology | 2012

Impaired survival and long-term neurological problems in benign meningioma

Hanna van Alkemade; Michelle de Leau; E.M.T. Dieleman; Jan W.P.F. Kardaun; Rob M. van Os; W. Peter Vandertop; Wouter R. van Furth; Lukas J.A. Stalpers

PURPOSE To assess long-term functional outcome and survival among patients with meningioma World Health Organization (WHO) grade I. METHODS Retrospective analysis of 205 patients after resection of WHO grade I intracranial meningioma from 1985 through 2003. Expected age- and sex-specific survival was calculated by applying Dutch life-table statistics to each patient for the individual duration of follow-up. Long-term functional outcome was assessed using a mailed questionnaire to the general practitioner. RESULTS The mean duration of follow-up was 11.5 years. Survival at 5, 10, 15, and 20 years was 92%, 81%, 63%, and 53%, respectively, which is significantly lower than the expected survival (94%, 86%, 78%, and 66%, respectively). Survival was worse with higher age (P < .001). Survival among patients younger than 45 years and older than 65 years was comparable to the expected survival but significantly worse among patients aged 45-65 years. Analysis of the cause of death suggests an excess mortality associated with both brain tumor death and stroke (P = .07). Recurrence rates at 5, 10, and 15 years were 18%, 26%, and 32%, respectively. Higher Simpson grade (P < .001) and lower age (P = .02) were associated with a higher recurrence rate. In 29 patients (14%) receiving radiotherapy, the 5-year recurrence rate was 18% and the 5-year survival was only 58%. Long-term functioning (≥ 5 years after last treatment) could be assessed in 89 long-term survivors: 29 patients (33%) showed no deficits, and 60 (67%) showed at least 1 neurological symptom, of whom 24 (27%) were unable to perform normal daily activities. CONCLUSION Long-term survival in WHO grade I meningioma is challenged in patients more than 45 years of age. Excess mortality seems to be associated with both tumor recurrence and stroke. The majority of patients have long-term neurological problems.

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David P. Noske

VU University Medical Center

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Thomas Wurdinger

VU University Medical Center

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Ben J. Slotman

VU University Medical Center

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Pieter Wesseling

Radboud University Nijmegen

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Jan J. Heimans

VU University Medical Center

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Sander Idema

VU University Medical Center

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