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Dive into the research topics where Arjen J. Witkamp is active.

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Featured researches published by Arjen J. Witkamp.


Expert Review of Anticancer Therapy | 2011

Localization of nonpalpable breast lesions

Emily L. Postma; Arjen J. Witkamp; Maurice A. A. J. van den Bosch; Helena M. Verkooijen; Richard van Hillegersberg

The introduction of mammography screening and improvements in diagnostic tools resulted in a major increase of breast cancers detectable as small, nonpalpable lesions suitable for breast-conserving treatment. Accurate preoperative localization of these cancers is a necessity. Several methods are available for localization, of which wire-guided localization is considered the current gold standard. Promising techniques are radio-guided occult lesion localization, radioactive seed localization and ultrasound-guided surgery. In this article, an overview of the various localization techniques is provided, describing advantages, shortcomings and effectiveness.


Clinical Cancer Research | 2017

Tumor-specific uptake of fluorescent bevacizumab-IRDye800CW microdosing in patients with primary breast cancer: a phase I feasibility study

Laetitia E. Lamberts; Maximillian Koch; Johannes S. de Jong; Arthur Adams; Jürgen Glatz; Mariëtte E.G. Kranendonk; Anton G.T. Terwisscha van Scheltinga; Liesbeth Jansen; Jakob de Vries; Marjolijn N. Lub-de Hooge; Carolien P. Schröder; Annelies Jorritsma-Smit; Matthijs D. Linssen; Esther de Boer; Bert van der Vegt; Wouter B. Nagengast; Sjoerd G. Elias; Sabrina Oliveira; Arjen J. Witkamp; Willem P. Th. M. Mali; Elsken van der Wall; Paul J. van Diest; Elisabeth G.E. de Vries; Vasilis Ntziachristos; Gooitzen M. van Dam

Purpose: To provide proof of principle of safety, breast tumor–specific uptake, and positive tumor margin assessment of the systemically administered near-infrared fluorescent tracer bevacizumab–IRDye800CW targeting VEGF-A in patients with breast cancer. Experimental Design: Twenty patients with primary invasive breast cancer eligible for primary surgery received 4.5 mg bevacizumab–IRDye800CW as intravenous bolus injection. Safety aspects were assessed as well as tracer uptake and tumor delineation during surgery and ex vivo in surgical specimens using an optical imaging system. Ex vivo multiplexed histopathology analyses were performed for evaluation of biodistribution of tracer uptake and coregistration of tumor tissue and healthy tissue. Results: None of the patients experienced adverse events. Tracer levels in primary tumor tissue were higher compared with those in the tumor margin (P < 0.05) and healthy tissue (P < 0.0001). VEGF-A tumor levels also correlated with tracer levels (r = 0.63, P < 0.0002). All but one tumor showed specific tracer uptake. Two of 20 surgically excised lumps contained microscopic positive margins detected ex vivo by fluorescent macro- and microscopy and confirmed at the cellular level. Conclusions: Our study shows that systemic administration of the bevacizumab–IRDye800CW tracer is safe for breast cancer guidance and confirms tumor and tumor margin uptake as evaluated by a systematic validation methodology. The findings are a step toward a phase II dose-finding study aimed at in vivo margin assessment and point to a novel drug assessment tool that provides a detailed picture of drug distribution in the tumor tissue. Clin Cancer Res; 23(11); 2730–41. ©2016 AACR.


British Journal of Surgery | 2013

Local recurrence after surgery for primary extra‐abdominal desmoid‐type fibromatosis

D. L. M. van Broekhoven; Cornelis Verhoef; Sjoerd G. Elias; Arjen J. Witkamp; J. M. van Gorp; B. van Geel; H. K. Wijrdeman; T. van Dalen

Desmoid‐type fibromatosis is a locally aggressive soft tissue tumour with a biological behaviour that varies between relatively indolent and progressive growth. Although there is a trend towards conservative treatment, surgery remains the standard treatment for extra‐abdominal desmoid tumours.


Genetics in Medicine | 2016

Does rapid genetic counseling and testing in newly diagnosed breast cancer patients cause additional psychosocial distress? results from a randomized clinical trial

Marijke R. Wevers; Margreet G. E. M. Ausems; Senno Verhoef; Eveline M. A. Bleiker; Daniela E. E. Hahn; Titia Brouwer; Frans B. L. Hogervorst; Rob B. van der Luijt; Thijs van Dalen; E. Theunissen; Bart van Ooijen Md; Marnix de Roos; Paul J. Borgstein; Bart C. Vrouenraets; Eline Vriens Md; Wim H. Bouma; Herman Rijna; Jp Vente; Jacobien M. Kieffer; Heiddis B. Valdimarsdottir; Emiel J. Th. Rutgers; Arjen J. Witkamp; Neil K. Aaronson

Purpose:Female breast cancer patients carrying a BRCA1/2 mutation have an increased risk of second primary breast cancer. Rapid genetic counseling and testing (RGCT) before surgery may influence choice of primary surgical treatment. In this article, we report on the psychosocial impact of RGCT.Methods:Newly diagnosed breast cancer patients at risk for carrying a BRCA1/2 mutation were randomized to an intervention group (offer of RGCT) or a usual care control group (ratio 2:1). Psychosocial impact and quality of life were assessed with the Impact of Events Scale, Hospital Anxiety and Depression Scale, Cancer Worry Scale, and the EORTC QLQ-C30 and QLQ-BR23. Assessments took place at study entry and at 6- and 12-month follow-up visits.Results:Between 2008 and 2010, 265 patients were recruited into the study. Completeness of follow-up data was more than 90%. Of the 178 women in the intervention group, 177 had genetic counseling, of whom 71 (40%) had rapid DNA testing and 59 (33%) received test results before surgery. Intention-to-treat and per-protocol analyses showed no statistically significant differences between groups over time in any of the psychosocial outcomes.Conclusions:In this study, RGCT in newly diagnosed breast cancer patients did not have any measurable adverse psychosocial effects.Genet Med 18 2, 137–144.


Cancer Research | 2017

Threshold Analysis and Biodistribution of Fluorescently Labeled Bevacizumab in Human Breast Cancer.

Maximilian Koch; Johannes S. de Jong; Jürgen Glatz; Panagiotis Symvoulidis; Laetitia E. Lamberts; Arthur Adams; Mariëtte E.G. Kranendonk; Anton G.T. Terwisscha van Scheltinga; Michaela Aichler; Liesbeth Jansen; Jakob de Vries; Marjolijn N. Lub-de Hooge; Carolien P. Schröder; Annelies Jorritsma-Smit; Matthijs D. Linssen; Esther de Boer; Bert van der Vegt; Wouter B. Nagengast; Sjoerd G. Elias; Sabrina Oliveira; Arjen J. Witkamp; Willem P. Th. M. Mali; Elsken van der Wall; P. Beatriz Garcia-Allende; Paul J. van Diest; Elisabeth G.E. de Vries; Axel Walch; Gooitzen M. van Dam; Vasilis Ntziachristos

In vivo tumor labeling with fluorescent agents may assist endoscopic and surgical guidance for cancer therapy as well as create opportunities to directly observe cancer biology in patients. However, malignant and nonmalignant tissues are usually distinguished on fluorescence images by applying empirically determined fluorescence intensity thresholds. Here, we report the development of fSTREAM, a set of analytic methods designed to streamline the analysis of surgically excised breast tissues by collecting and statistically processing hybrid multiscale fluorescence, color, and histology readouts toward precision fluorescence imaging. fSTREAM addresses core questions of how to relate fluorescence intensity to tumor tissue and how to quantitatively assign a normalized threshold that sufficiently differentiates tumor tissue from healthy tissue. Using fSTREAM we assessed human breast tumors stained in vivo with fluorescent bevacizumab at microdose levels. Showing that detection of such levels is achievable, we validated fSTREAM for high-resolution mapping of the spatial pattern of labeled antibody and its relation to the underlying cancer pathophysiology and tumor border on a per patient basis. We demonstrated a 98% sensitivity and 79% specificity when using labeled bevacizumab to outline the tumor mass. Overall, our results illustrate a quantitative approach to relate fluorescence signals to malignant tissues and improve the theranostic application of fluorescence molecular imaging. Cancer Res; 77(3); 623-31. ©2016 AACR.


Journal of Medical Internet Research | 2014

Tablet, Web-Based, or Paper Questionnaires for Measuring Anxiety in Patients Suspected of Breast Cancer: Patients' Preferences and Quality of Collected Data

M. W. Barentsz; Hester Wessels; Paul J. van Diest; Ruud M. Pijnappel; Cees Haaring; Carmen van der Pol; Arjen J. Witkamp; Maurice A. A. J. van den Bosch; Helena M. Verkooijen

Background Electronic applications are increasingly being used in hospitals for numerous purposes. Objective Our aim was to assess differences in the characteristics of patients who choose paper versus electronic questionnaires and to evaluate the data quality of both approaches. Methods Between October 2012 and June 2013, 136 patients participated in a study on diagnosis-induced stress and anxiety. Patients were asked to fill out questionnaires at six different moments during the diagnostic phase. They were given the opportunity to fill out the questionnaires on paper or electronically (a combination of tablet and Web-based questionnaires). Demographic characteristics and completeness of returned data were compared between groups. Results Nearly two-thirds of patients (88/136, 64.7%) chose to fill out the questionnaires on paper, and just over a third (48/136, 35.3%) preferred the electronic option. Patients choosing electronic questionnaires were significantly younger (mean 47.3 years vs mean 53.5 in the paper group, P=.01) and higher educated (P=.004). There was significantly more missing information (ie, at least one question not answered) in the paper group during the diagnostic day compared to the electronic group (using a tablet) (28/88 vs 1/48, P<.001). However, in the week after the diagnostic day, missing information was significantly higher in the electronic group (Web-based questionnaires) compared to the paper group (41/48 vs 38/88, P<.001). Conclusions Younger patients and patients with a higher level of education have a preference towards filling out questionnaires electronically. In the hospital, a tablet is an excellent medium for patients to fill out questionnaires with very little missing information. However, for filling out questionnaires at home, paper questionnaires resulted in a better response than Web-based questionnaires.


Ejso | 2014

Radiofrequency ablation of small breast tumours: evaluation of a novel bipolar cool-tip application.

L. Waaijer; D.L. Kreb; M.A. Fernandez Gallardo; P.S.N. Van Rossum; Emily L. Postma; R. Koelemij; P. J. van Diest; J. H. G. M. Klaessens; Arjen J. Witkamp; R. van Hillegersberg

BACKGROUND Although radiofrequency ablation (RFA) is promising for the local treatment of breast cancer, burns are a frequent complication. The safety and efficacy of a new technique with a bipolar RFA electrode was evaluated. METHODS Dosimetry was assessed ex vivo in bovine mammary tissue, applying power settings of 5-15 W with 10-20 min exposure and 3.0-12.0 kJ to a 20-mm active length bipolar internally cooled needle-electrode. Subsequently, in 15 women with invasive breast carcinoma ≤2.0 cm diameter ultrasound-guided RFA was performed followed by immediate resection. RESULTS An ablation zone of 2.5 cm was reached in the ex vivo experiments at 15 W at 9.0 kJ administered energy. Histopathology revealed complete cell death in 10 of 13 patients (77%); in 3 patients partial ablation was due to inaccurate probe positioning. In 1 patient a pneumothorax was caused by the probe placement, treated conservatively. No burns occurred. CONCLUSIONS Ultrasound-guided RFA with a bipolar needle-electrode appears to be a safe local treatment technique for invasive breast cancer up to 2 cm. Ways to improve placement of the probe and direct monitoring of the ablation-effect should be the aim of further research.


Modern Pathology | 2013

Analysis of copy number changes on chromosome 16q in male breast cancer by multiplex ligation-dependent probe amplification

Miangela M. Lacle; Robert Kornegoor; Cathy B. Moelans; Anoek H Maes-Verschuur; Carmen C. van der Pol; Arjen J. Witkamp; Elsken van der Wall; Josef Rueschoff; Horst Buerger; Paul J. van Diest

Gene copy number changes have an important role in carcinogenesis and could serve as potential biomarkers for prognosis and targets for therapy. Copy number changes mapping to chromosome 16 have been reported to be the most frequent alteration observed in female breast cancer and a loss on 16q has been shown to be associated with low grade and better prognosis. In the present study, we aimed to characterize copy number changes on 16q in a group of 135 male breast cancers using a novel multiplex ligation-dependent probe amplification kit. One hundred and twelve out of 135 (83%) male breast cancer showed copy number changes of at least one gene on chromosome 16, with frequent loss of 16q (71/135; 53%), either partial (66/135; 49%) or whole arm loss (5/135; 4%). Losses on 16q were thereby less often seen in male breast cancer than previously described in female breast cancer. Loss on 16q was significantly correlated with favorable clinicopathological features such as negative lymph node status, small tumor size, and low grade. Copy number gain of almost all genes on the short arm was also significantly correlated with lymph node negative status. A combination of 16q loss and 16p gain correlated even stronger with negative lymph node status (n=112; P=0.012), which was also underlined by unsupervised clustering. In conclusion, copy number loss on 16q is less frequent in male breast cancer than in female breast cancer, providing further evidence that male breast cancer and female breast cancer are genetically different. Gain on 16p and loss of 16q identify a group of male breast cancer with low propensity to develop lymph node metastases.


International Journal of Cancer | 2011

Progression risk of columnar cell lesions of the breast diagnosed in core needle biopsies.

Anoek H J Verschuur-Maes; Arjen J. Witkamp; Peter C. de Bruin; Elsken van der Wall; Paul J. van Diest

Columnar cell lesions (CCLs) of the breast are recognized as putative precursor lesions of invasive carcinoma, but their management remains controversial. We therefore conducted a retrospective study on 311 CCLs, diagnosed in 4,164 14‐gauge core needle biopsies (CNB): 221 CCLs without atypia (CCL), 69 with atypia (CCL‐A), and 21 atypical ductal hyperplasias originating in CCL (ADH‐CCL). Two groups were identified: “immediate treatment” group undergoing excision within four months after the CNB diagnosis of CCL (N = 52) and the “wait‐and‐see” group followed up to 8 years (median 3.5 years, N = 259). In 7 of 31 women (22.5%, 1 CCL, 4 CCL‐A, 2 ADH‐CCL) who underwent immediate surgical excision and were initially biopsied for microcalcifications, ductal carcinoma in situ (DCIS) was present and in 2/31 women (6.5%, 1 CCL, 1 CCL‐A) invasive carcinoma. In 2/21 excisions (9.5%, 1 CCL, 1 CCL‐A) initially biopsied for a density, DCIS was present and invasive carcinoma in 5/21 excisions (23.8%, 2 CCL, 3 CCL‐A). In the wait‐and‐see group, 9/259 women (3.5%) developed invasive carcinoma, 6 ipsi, and 3 contralaterally. Progression risks of CCL‐A and ADH‐CCL were 18% and 22%,versus 2% for CCL without atypia (p < 0.001). In conclusion, CCL‐A or ADH‐CCL in a CNB were associated with a high risk of DCIS/invasive carcinoma in immediate surgical excision biopsies. The 8‐years progression risks for CCL‐A and ADH‐CCL were around 20%. This illustrates that an atypical CCL in a CNB may signal the presence of concurrent lesions or development of advanced lesions in future and may justify (“mini”) surgical excision.


Ejso | 2015

Prediction of positive resection margins in patients with non-palpable breast cancer

M. W. Barentsz; Emily L. Postma; T. van Dalen; M. A. A. J. van den Bosch; Hui Miao; Paul D. Gobardhan; L.E. van den Hout; Ruud M. Pijnappel; Arjen J. Witkamp; P. J. van Diest; R. van Hillegersberg; Helena M. Verkooijen

BACKGROUND In patients undergoing breast conserving surgery for non-palpable breast cancer, obtaining tumour free resection margins is important to prevent reexcision and local recurrence. We developed a model to predict positive resection margins in patients undergoing breast conserving surgery for non-palpable invasive breast cancer. METHODS A total of 576 patients with non-palpable invasive breast cancer underwent breast conserving surgery in five hospitals in the Netherlands. A prediction model for positive resection margins was developed using multivariate logistic regression. Calibration and discrimination of the model were assessed and the model was internally validated by bootstrapping. RESULTS Positive resection margins were present in 69/576 (12%) patients. Factors independently associated with positive resection margins included mammographic microcalcifications (OR 2.14, 1.22-3.77), tumour size (OR 1.75, 1.20-2.56), presence of DCIS (OR 2.61, 1.41-4.82), Bloom and Richardson grade 2/3 (OR 1.82, 1.05-3.14), and caudal location of the lesion (OR 2.4, 1.35-4.27). The model was well calibrated and moderately able to discriminate between patients with positive versus negative resection margins (AUC 0.70, 95% CI, 0.63-0.77, and 0.69 after internal validation). CONCLUSION The presented prediction model is moderately able to differentiate between women with high versus low risk of positive margins, and may be useful for surgical planning and preoperative patient counselling.

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