Boudewijn E. C. Plaat

Dr. Boudewijn E. C. Plaat

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Research Focus & Metrics

Academic Career Length

33Years (1994-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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18 September 2000 in Journal of Clinical Oncology
Verified
Journal Article
Closed access
BPBoudewijn E. C. Plaat
Boudewijn E. C. Plaat
HHHarry Hollema
Harry Hollema
WMWillemina M. Molenaar
Willemina M. Molenaar
GBGerben H. Torn Broers
Gerben H. Torn Broers
JPJustin Pijpe
Justin Pijpe
WGWinette T. A. van der Graaf
Winette T. A. van der Graaf
PURPOSE: Several studies have reported clinical behavior and chemotherapy resistance in leiomyosarcomas, but these studies did not differentiate between soft tissue leiomyosarcomas (LMS) and malignant gastrointestinal stromal tumors (GIST). Multidrug resistance (MDR) has been associated with the expression of P-glycoprotein (P-gp), multidrug resistance protein (MRP1), and lung resistance protein (LRP). The aim of the present study was to compare LMS and GIST with respect to clinical outcome and MDR parameters. PATIENTS AND METHODS: Clinical outcome was evaluated in 29 patients with a primary deep-seated LMS and 26 patients with a primary malignant GIST. Paraffin-embedded material, available for 26 patients with LMS and 25 with GIST, was used for immunohistochemical detection of P-gp, MRP1, LRP, and c-kit. RESULTS: Mean overall survival (OS) was 72 months for LMS patients and 31 months for GIST patients (P < .05). Metastases occurred in 16 (59%) of 27 assessable LMS patients and in 10 (56%) of 18 assessable GIST patients. LMS predominantly metastasized to the lungs (14 of 16 patients), whereas GIST tended to spread to the liver (five of 10 patients) and the abdominal cavity (three of 10 patients; P < .001). P-gp and MRP1 expression was more pronounced in GIST than in LMS (P < .05): the mean percentage of P-gp expressing cells was 13.4% in patients with LMS and 38.4% in patients with GIST, and the mean percentage MRP1 expressing cells was 13.3% in patients with LMS and 35.4% in patients with GIST. LRP expression did not differ between LMS and GIST. c-kit was expressed in 5% of the LMS patients and in 68% of the GIST patients. CONCLUSION: LMS patients have a better survival than GIST patients, and the metastatic pattern is different. Expression of MDR proteins in LMS is less pronounced than in GIST.


16 August 2023 in Nature Communications
Verified
Journal Article
Open access
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JWJaron G. de Wit
Jaron G. de Wit
JVJasper Vonk
Jasper Vonk
FVFloris Jan Voskuil
Floris Jan Voskuil
Sebastiaan de VisscherSebastiaan de Visscher
Sebastiaan de Visscher
KSKees-Pieter Schepman
Kees-Pieter Schepman
Max Johannes Hendrikus WitjesMax Johannes Hendrikus Witjes
Max Johannes Hendrikus Witjes
Inadequate surgical margins occur frequently in oral squamous cell carcinoma surgery. Fluorescence molecular imaging (FMI) has been explored for intraoperative margin assessment, but data are limited to phase-I studies. In this single-arm phase-II study (NCT03134846), our primary endpoints were to determine the sensitivity, specificity and positive predictive value of cetuximab-800CW for tumor-positive margins detection. Secondary endpoints were safety, close margin detection rate and intrinsic cetuximab-800CW fluorescence. In 65 patients with 66 tumors, cetuximab-800CW was well-tolerated. Fluorescent spots identified in the surgical margin with signal-to-background ratios (SBR) of ≥2 identify tumor-positive margins with 100% sensitivity, 85.9% specificity, 58.3% positive predictive value, and 100% negative predictive value. An SBR of ≥1.5 identifies close margins with 70.3% sensitivity, 76.1% specificity, 60.5% positive predictive value, and 83.1% negative predictive value. Performing frozen section analysis aimed at the fluorescent spots with an SBR of ≥1.5 enables safe, intraoperative adjustment of surgical margins.

1 December 2016 in Oral Oncology
Verified
Journal Article
Open access
TLTom P. van der Laan
Tom P. van der Laan
RIRené Iepsma
René Iepsma
MWMax J.H. Witjes
Max J.H. Witjes
BLBernard F.A.M. van der Laan
Bernard F.A.M. van der Laan
BPBoudewijn E. C. Plaat
Boudewijn E. C. Plaat
Gyorgy B HalmosGyorgy B Halmos
Gyorgy B Halmos
The aim of this meta-analysis was to provide treatment guidelines for sinonasal neuroendocrine carcinoma (SNC) by combining all available data in the literature. A literature search for all studies concerning SNC was performed against the MEDLINE and EMBASE databases. Available clinical data was normalized, pooled, and statistically analyzed. A total of 701 cases of SNC were available for analysis, comprising 127 well or moderately differentiated sinonasal neuroendocrine carcinomas (SNEC), 459 sinonasal undifferentiated carcinoma (SNUC) and 115 sinonasal small cell carcinoma (SmCC). Tumor type was the most important predictor of survival, with a 5-year disease-specific survival (DSS) of 70.2% for SNEC, 35.9% for SNUC and 46.1% for SmCC. Tumor stage on presentation was of limited value in predicting survival or response to treatment. Overall, the application of surgery yielded significantly better results (5-year DSS 52.2% versus 30.1%, p<0.001). In SNUC, radiotherapy was a beneficial supplement to surgery (5-year DSS 54.7% versus 15.7%, p=0.027), while radiotherapy as monotherapy performed poorly (5-year DSS 17.9%). Chemotherapy did not appear to contribute to survival. Based on these findings, we can conclude that the most important predictors of survival in SNC are differentiation grade and the associated choice of treatment modality. In contrast to other head and neck cancers, tumor staging appears of limited value in predicting survival or deciding on a treatment strategy. Surgery should be the cornerstone of treatment, supplemented by radiotherapy in poorly differentiated subtypes (SNUC, SmCC). Chemotherapy does not appear to contribute to survival.

1 August 2021 in European Journal of Surgical Oncology
Verified
Journal Article
Open access
RSRosanne C. Schoonbeek
Rosanne C. Schoonbeek
JZJulia Zwertbroek
Julia Zwertbroek
BPBoudewijn E. C. Plaat
Boudewijn E. C. Plaat
RTRobert P. Takes
Robert P. Takes
JRJohn A. Ridge
John A. Ridge
GHGyörgy B. Halmos
György B. Halmos
Head and neck cancers (HNC) are relatively fast-growing tumours, and delay in treatment initiation is associated with tumour progression and adverse outcome. An overview of factors contributing to delay can provide critical insights on necessary adjustments to optimize care pathways. This systematic review aims to identify factors associated with delay and summarize the effect of delay on oncological outcome measures. A search strategy was conducted according to PRISMA guidelines to search electronic databases for studies assessing the carepathway interval (days between first visit in head and neck oncology center and treatment initiation) and/or time-to-treatment-initiation interval (days between histological diagnosis and treatment initiation) and 1) determinants of delay and/or 2) effect of delay on outcome within these timeframes. Due to heterogeneity between included studies, a meta-analysis was not possible. Fifty-two studies were eligible for quantitative analysis. Non-Caucasian race, academic setting, Medicaid/no insurance and radiotherapy as primary treatment were associated with delay. Advanced tumour stage was related to increased time-to-treatment initiation in the four common sites combined (oral cavity, oropharynx, hypopharynx, larynx). Separate determinants for delay in different tumour locations were identified. In laryngeal, oral cavity cancer and the four common HNC sites combined, delay in start of treatment is associated with decreased overall survival, although no cut-off time point could be determined. Race, facility type, type of insurance and radiotherapy as primary treatment were associated with delay and subsequent inferior survival in the four common sites combined.

1 October 2016 in Journal of the American Academy of Dermatology
Verified
Journal Article
Closed access
MHMarjolijn S. Haisma
Marjolijn S. Haisma
BPBoudewijn E. C. Plaat
Boudewijn E. C. Plaat
HBHendrik P. Bijl
Hendrik P. Bijl
JRJan L.N. Roodenburg
Jan L.N. Roodenburg
GDGilles F.H. Diercks
Gilles F.H. Diercks
JTJorrit B. Terra
Jorrit B. Terra