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Dive into the research topics where Charlotte L. Zuur is active.

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Featured researches published by Charlotte L. Zuur.


European Journal of Nuclear Medicine and Molecular Imaging | 2012

Concomitant radio- and fluorescence-guided sentinel lymph node biopsy in squamous cell carcinoma of the oral cavity using ICG-(99m)Tc-nanocolloid.

Nynke S. van den Berg; Oscar R. Brouwer; W. Martin C. Klop; Baris Karakullukcu; Charlotte L. Zuur; I. Bing Tan; Alfons J. M. Balm; Michiel W. M. van den Brekel; Renato A. Valdés Olmos; Fijs W. B. van Leeuwen

PurposeFor oral cavity malignancies, sentinel lymph node (SLN) mapping is performed by injecting a radiocolloid around the primary tumour followed by lymphoscintigraphy. Surgically, SLNs can then be localized using a handheld gamma ray detection probe. The aim of this study was to evaluate the added value of intraoperative fluorescence imaging to the conventional radioguided procedure. For this we used indocyanine green (ICG)‐99mTc‐nanocolloid, a hybrid tracer that is both radioactive and fluorescent.MethodsFourteen patients with oral cavity squamous cell carcinoma were peritumourally injected with ICG-99mTc-nanocolloid. SLNs were preoperatively identified with lymphoscintigraphy followed by single photon emission computed tomography (SPECT)/CT for anatomical localization. During surgery, SLNs were detected with a handheld gamma ray detection probe and a handheld near-infrared fluorescence camera. Pre-incision and post-excision imaging with a portable gamma camera was performed to confirm complete removal of all SLNs.ResultsSLNs were preoperatively identified using the radioactive signature of ICG-99mTc-nanocolloid. Intraoperatively, 43 SLNs could be localized and excised with combined radio- and fluorescence guidance. Additionally, in four patients, an SLN located close to the primary injection site (in three patients this SLN was located in level I) could only be intraoperatively localized using fluorescence imaging. Pathological analysis of the SLNs revealed a metastasis in one patient.ConclusionCombined preoperative SLN identification and intraoperative radio- and fluorescence guidance during SLN biopsies for oral cavity cancer proved feasible using ICG-99mTc-nanocolloid. The addition of fluorescence imaging was shown to be of particular value when SLNs were located in close proximity to the primary tumour.


Journal of Clinical Oncology | 2007

Ototoxicity in a Randomized Phase III Trial of Intra-Arterial Compared With Intravenous Cisplatin Chemoradiation in Patients With Locally Advanced Head and Neck Cancer

Charlotte L. Zuur; Yvonne J.W. Simis; Pauline E. Lansdaal; Augustinus A. M. Hart; Jan H. Schornagel; Wouter A. Dreschler; Coen R. N. Rasch; Alfons J. J. Balm

PURPOSE Cisplatin concomitantly administered with radiotherapy is increasingly used in locally advanced head and neck squamous cell carcinoma. We aimed to compare the incidence of hearing loss between patients treated with intra-arterial high-dose cisplatin chemoradiation with sodium thiosulfate (CRT-IA) and intravenous high-dose cisplatin chemoradiation without sodium thiosulfate (CRT-IV). PATIENTS AND METHODS We conducted a prospective analysis of hearing thresholds at low and (ultra-) high frequencies obtained before, during, and after treatment in 158 patients. Patients were randomly assigned for either CRT-IA (150 mg/m(2), four courses) with sodium thiosulfate cisplatin neutralization or CRT-IV (100 mg/m(2), three courses) without rescue. All patients received concomitant radiation therapy (RT; 70 Gy). RESULTS CRT-IA resulted in approximately 10% less hearing loss at frequencies vital for speech perception, compared with CRT-IV (P < .001). In CRT-IA, fewer ears qualified for hearing aids (36% v 49%; P = .03). However, in both treatment arms, the incidence expressed in National Cancer Institute Common Terminology Criteria of Adverse Events (version 3) did not deviate (P > .14). Age, cumulative cisplatin dose, cumulative RT dose, and the considered frequency area determine the degree of hearing loss (P < .001). Cisplatin induced increasing hearing loss of 24% to 60% with increasing frequencies. RT induced hearing loss at speech frequencies of 9% to 12%. CONCLUSION Depending on the criteria used to assess hearing loss due to treatment, differences in ototoxicity between CRT-IA and CRT-IV were found in favor of CRT-IA. It is desirable to specify hearing loss criteria toward frequencies vital for speech perception, and to refine grading scales to reveal subtle and clinically relevant dissimilarities in ototoxicity between different treatment protocols.


Archives of Otolaryngology-head & Neck Surgery | 2012

Total Laryngectomy for a Dysfunctional Larynx After (Chemo)Radiotherapy

Eleonoor A. R. Theunissen; Adriana J. Timmermans; Charlotte L. Zuur; O. Hamming-Vrieze; Jan Paul de Boer; Frans J. M. Hilgers; Michiel W. M. van den Brekel

OBJECTIVE To evaluate the functional outcomes after total laryngectomy (TLE) for a dysfunctional larynx in patients with head and neck cancer that is in complete remission after (chemo)radiotherapy. DESIGN Retrospective cohort study. SETTING Tertiary comprehensive cancer center. PATIENTS The study included 25 patients from a cohort of 217 consecutive patients with TLE who were treated between January 2000 and July 2010. The inclusion criteria for this subgroup analysis were complete remission and functional problems for which TLE was considered to be the only resolution. Quality of life assessment was carried out using the European Organization for Research and Treatment of Cancer Quality of Life C30 and Head and Neck Module 35 questionnaires and an additional study-specific questionnaire covering functional aspects, such as swallowing and dyspnea, in more detail. INTERVENTION Total laryngectomy. MAIN OUTCOME MEASURES Morbidity, mortality, and functional outcomes. RESULTS The indication for TLE was chronic aspiration with or without recurrent pneumonia (n = 15 [60%]), debilitating dyspnea (n = 8 [32%]), and persistent profuse hemorrhage (radiation ulcer) (n = 2 [8%]). After TLE, 14 of the 25 patients (56%) had 20 major postoperative complications, including 11 pharyngocutaneous fistulas, requiring additional treatment. Tube feeding and recurrent pneumonia incidence had decreased from 80% and 28% to 29% and 0%, respectively, 2 years after surgery. Prosthetic voice rehabilitation was possible in 19 patients (76%). Two years after surgery, 10 of 14 patients (71%) still reported TLE-related pulmonary problems despite the consistent use of a heat and moisture exchanger. The 5-year overall survival rate was 35%. CONCLUSIONS Total laryngectomy for a dysfunctional larynx tends to have a high complication rate. However, in this study, the initial functional problems (aspiration, recurrent pneumonia, and dyspnea) did not recur. Tube feeding was significantly reduced, and the quality of life of the surviving patients appeared to be reasonable.


Annals of Otology, Rhinology, and Laryngology | 2014

A New Grading System for Ototoxicity in Adults

Eleonoor A.R. Theunissen; Wouter A. Dreschler; Merel N. Latenstein; Coen R. N. Rasch; Sieberen van der Baan; Jan Paul de Boer; Alfons J. M. Balm; Charlotte L. Zuur

Objective: This study aimed to propose an ototoxicity grading system sensitive to the effect of ototoxicity on specific daily life situations like speech intelligibility and the perception of ultra-high sounds and to test its feasibility compared to current criteria. Methods: Pure tone averages (PTAs) for speech perception (1-2-4 kHz) and ultra-high frequencies (8-10-12.5 kHz) were incorporated. Threshold shift and hearing level posttreatment were taken into account. Criteria were tested on head and neck cancer patients treated with (chemo-)radiotherapy ([C]RT) and compared with the Common Terminology Criteria for Adverse Events version 4 (CTCAEv4) and the American Speech-Language-Hearing Association criteria (ASHA). Results: Grades 1 and 2 were based on threshold shifts from baseline (in dB) and subjective complaints. Grades 3 and 4 were defined as treatment-induced hearing loss of ≥ 35 dB at PTA 1-2-4 kHz and ≥ 70 dB at PTA 1-2-4 kHz, respectively. In high-dose cisplatin CRT incidences by the new criteria, CTCAEv4 and ASHA were comparable (78%-88%). In RT and low-dose cisplatin CRT, incidences were 36% to 39% in the new criteria versus 22% to 53% in CTCAEv4 and ASHA. Conclusion: The new criteria show an increased sensitivity to ototoxicity compared to CTCAEv4 and ASHA and provide insight into the effect of hearing loss on certain daily life situations. The new grading system seems feasible for clinic and research purposes.


Clinical Otolaryngology | 2016

Hearing loss in survivors of childhood head and neck rhabdomyosarcoma: a long-term follow-up study

Reineke A. Schoot; Eleonoor A.R. Theunissen; Olga Slater; Marta Lopez-Yurda; Charlotte L. Zuur; Mark N. Gaze; Yen-Ching Chang; Henry Mandeville; Jennifer E. Gains; Kaukab Rajput; Bradley R. Pieters; Raquel Dávila Fajardo; Rishi Talwar; Huib N. Caron; Alfons J. M. Balm; Wouter A. Dreschler; Johannes H. M. Merks

To determine the hearing status of survivors treated for head and neck rhabdomyosarcoma (HNRMS) at long‐term follow‐up.


Cancers | 2015

Feasibility of Primary Tumor Culture Models and Preclinical Prediction Assays for Head and Neck Cancer: A Narrative Review

Amy J.C. Dohmen; Justin E. Swartz; Michiel W. M. van den Brekel; Stefan M. Willems; René Spijker; Jacques Neefjes; Charlotte L. Zuur

Primary human tumor culture models allow for individualized drug sensitivity testing and are therefore a promising technique to achieve personalized treatment for cancer patients. This would especially be of interest for patients with advanced stage head and neck cancer. They are extensively treated with surgery, usually in combination with high-dose cisplatin chemoradiation. However, adding cisplatin to radiotherapy is associated with an increase in severe acute toxicity, while conferring only a minor overall survival benefit. Hence, there is a strong need for a preclinical model to identify patients that will respond to the intended treatment regimen and to test novel drugs. One of such models is the technique of culturing primary human tumor tissue. This review discusses the feasibility and success rate of existing primary head and neck tumor culturing techniques and their corresponding chemo- and radiosensitivity assays. A comprehensive literature search was performed and success factors for culturing in vitro are debated, together with the actual value of these models as preclinical prediction assay for individual patients. With this review, we aim to fill a gap in the understanding of primary culture models from head and neck tumors, with potential importance for other tumor types as well.


Radiotherapy and Oncology | 2018

The impact of margin reduction on outcome and toxicity in head and neck cancer patients treated with image-guided volumetric modulated arc therapy (VMAT)

Arash Navran; W. Heemsbergen; T.M. Janssen; O. Hamming-Vrieze; M. Jonker; Charlotte L. Zuur; Marcel Verheij; P. Remeijer; Jan-Jakob Sonke; Michiel W. M. van den Brekel; Abrahim Al-Mamgani

BACKGROUND AND PURPOSE In recent decades, outcomes of patients with head and neck cancer (HNC) have improved as a result of implementing several strategies, such as chemoradiation. However, these improvements were achieved at the cost of increased toxicity. One way to reduce radiation-related toxicity is by reducing the margins. MATERIALS AND METHODS Between 2013 and 2016, 206 consecutive patients were treated with CTV-PTV margin of 5 mm and subsequently 208 patients with 3 mm margin. This study evaluates the impact of reducing clinical target volume (CTV) to planning target volume (PTV) margin on outcome and toxicity. RESULTS All patients were treated with volumetric modulated arc therapy (VMAT) with daily-image guidance using cone-beam CT (CBCT). Overall acute grade 3 toxicity was significantly lower in 3 mm-group, compared to 5 mm-group (53.8% vs. 65%, respectively, p = 0.032). The same was true for acute grade 3 mucositis (30.8% vs. 42.2%, p = 0.008) and for acute grade 3 dysphagia (feeding tube-dependence) (22.1% vs. 33.5%, p = 0.026). The incidence of ongoing feeding tube-dependence after 3 months of radiotherapy was 11.1% and 20.4%, respectively (p = 0.012). The 2-year incidence of late grade ≥2 xerostomia was 15.8% and 19.4% (p = 0.8). The 2-year loco-regional control rates of patients treated in 3 mm and 5 mm-groups were 79.9% and 79.2% (p = 1.0). The figures for disease-free survival were 71.5% and 72.7 (p = 0.6) and for overall survival were 75.2% and 75.1% (p = 0.9). CONCLUSION Reducing the CTV-PTV margin from 5 to 3 mm combined with daily CBCT-guided VMAT reduced the severity, frequency, and duration of radiation-related toxicity without jeopardizing outcome.


Oncotarget | 2018

Sponge-supported cultures of primary head and neck tumors for an optimized preclinical model

Amy J.C. Dohmen; Joyce Sanders; Sander Canisius; Ekaterina S. Jordanova; Else A. Aalbersberg; Michiel W. M. van den Brekel; Jacques Neefjes; Charlotte L. Zuur

Treatment of advanced head and neck cancer is associated with low survival, high toxicity and a widely divergent individual response. The sponge-gel-supported histoculture model was previously developed to serve as a preclinical model for predicting individual treatment responses. We aimed to optimize the sponge-gel-supported histoculture model and provide more insight in cell specific behaviour by evaluating the tumor and its microenvironment using immunohistochemistry. We collected fresh tumor biopsies from 72 untreated patients and cultured them for 7 days. Biopsies from 57 patients (79%) were successfully cultured and 1451 tumor fragments (95.4%) were evaluated. Fragments were scored for percentage of tumor, tumor viability and proliferation, EGF-receptor expression and presence of T-cells and macrophages. Median tumor percentage increased from 53% at day 0 to 80% at day 7. Viability and proliferation decreased after 7 days, from 90% to 30% and from 30% to 10%, respectively. Addition of EGF, folic acid and hydrocortisone can lead to improved viability and proliferation, however this was not systematically observed. No patient subgroup could be identified with higher culture success rates. Immune cells were still present at day 7, illustrating that the tumor microenvironment is sustained. EGF supplementation did not increase viability and proliferation in patients overexpressing EGF-Receptor.


Oncotarget | 2017

Identification of a novel ATM inhibitor with cancer cell specific radiosensitization activity

Amy J.C. Dohmen; Xiaohang Qiao; Anja Duursma; Ruud H. Wijdeven; Cor Lieftink; Floor Hageman; Ben Morris; Pasi Halonen; Conchita Vens; Michiel W. M. van den Brekel; Huib Ovaa; Jacques Neefjes; Charlotte L. Zuur

Treatment of advanced head and neck squamous cell carcinoma (HNSCC) is plagued by low survival and high recurrence rates, despite multimodal therapies. Presently, cisplatin or cetuximab is used in combination with radiotherapy which has resulted in minor survival benefits but increased severe toxicities relative to RT alone. This underscores the urgent need for improved tumor-specific radiosensitizers for better control with lower toxicities. In a small molecule screen targeting kinases, performed on three HNSCC cell lines, we identified GSK635416A as a novel radiosensitizer. The extent of radiosensitization by GSK635416A outperformed the radiosensitization observed with cisplatin and cetuximab in our models, while exhibiting virtually no cytotoxicity in the absence of radiation and in normal fibroblast cells. Radiation induced phosphorylation of ATM was inhibited by GSK635416A. GSK63541A increased DNA double strand breaks after radiation and GSK63541A mediated radiosensitization was lacking in ATM-mutated cells thereby further supporting the ATM inhibiting properties of GSK63541A. As a novel ATM inhibitor with highly selective radiosensitizing activity, GSK635416A holds promise as a lead in the development of drugs active in potentiating radiotherapy for HNSCC and other cancer types.Treatment of advanced head and neck squamous cell carcinoma (HNSCC) is plagued by low survival and high recurrence rates, despite multimodal therapies. Presently, cisplatin or cetuximab is used in combination with radiotherapy which has resulted in minor survival benefits but increased severe toxicities relative to RT alone. This underscores the urgent need for improved tumor-specific radiosensitizers for better control with lower toxicities. In a small molecule screen targeting kinases, performed on three HNSCC cell lines, we identified GSK635416A as a novel radiosensitizer. The extent of radiosensitization by GSK635416A outperformed the radiosensitization observed with cisplatin and cetuximab in our models, while exhibiting virtually no cytotoxicity in the absence of radiation and in normal fibroblast cells. Radiation induced phosphorylation of ATM was inhibited by GSK635416A. GSK63541A increased DNA double strand breaks after radiation and GSK63541A mediated radiosensitization was lacking in ATM-mutated cells thereby further supporting the ATM inhibiting properties of GSK63541A. As a novel ATM inhibitor with highly selective radiosensitizing activity, GSK635416A holds promise as a lead in the development of drugs active in potentiating radiotherapy for HNSCC and other cancer types.


Archive | 2011

Preclinical Models of Head and Neck Squamous Cell Carcinoma

Michiel W. M. van den Brekel; Charlotte L. Zuur; Stephen P. Malkoski; Xiao-Jing Wang

Model systems are irreplaceable to study cancer. Although the best model system is human cancer in man, research in patients is restricted by ethical and financial restraints. Furthermore, experiments cannot be repeated and patient numbers are limited. Tumor cell cultures are the most versatile system to study cancer cells. They allow for repeated experiments in controlled conditions, are relatively inexpensive and are ideal to study genes, pathways, and tumor response. Mouse models enable to study cancer behavior and carcinogenesis in vivo and many different model systems are available. Apart from xenografts in immune compromised mice, transplantation of oral mice tumors in syngeneic mice, animals developing oral cancer using carcinogen exposure and genetically modified mice can be used. All these models, however, have advantages and limitations that will be discussed in this chapter.

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Alfons J. M. Balm

Netherlands Cancer Institute

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Abrahim Al-Mamgani

Netherlands Cancer Institute

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Amy J.C. Dohmen

Netherlands Cancer Institute

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Jacques Neefjes

Leiden University Medical Center

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J.P. de Boer

Netherlands Cancer Institute

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