Kristien Keymeulen

Maastricht Universitair Medisch Centrum, Maestricht, Limburg, Netherlands

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Publications (16)47.2 Total impact

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    ABSTRACT: The aim of this review is to investigate the effect of timing of the reconstruction and radiotherapy, with respect to complication rate and cosmetic outcome, with a special focus on the timing of the placement of the definite implant.
    European journal of cancer (Oxford, England: 1990) 08/2014; · 4.12 Impact Factor
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    ABSTRACT: INTRODUCTION: Cyclooxygenase-2 (COX-2) is frequently over-expressed in primary breast cancer. In transgenic breast cancer models, over-expression of COX-2 leads to tumour formation while COX-2 inhibition exerts anti-tumour effects in breast cancer cell lines. To further determine the effect of COX-2 inhibition in primary breast cancer, here we aimed at identifying transcriptional changes in breast cancer tissues of patients treated with the selective COX-2 inhibitor celecoxib. METHODS: In a single-centre double-blinded phase II study, thirty-seven breast cancer patients were randomised to receive either pre-operative celecoxib (400 mg) twice daily for two to three weeks (n = 22) or a placebo likewise (n = 15). Gene expression in fresh-frozen pre-surgical biopsies (before treatment) and surgical excision specimens (after treatment) was profiled by using Affymetrix arrays. Differentially expressed genes and altered pathways were bioinformatically identified. Expression of selected genes was validated by quantitative PCR (qPCR). Immunohistochemical protein expression analyses of the proliferation marker Ki-67, the apoptosis marker cleaved caspase-3, and the neo-angiogenesis marker CD34 served to evaluate biological response. RESULTS: We identified 972 and 586 significantly up- and down-regulated genes, respectively, in celecoxib-treated specimens. Significant expression changes in six out of eight genes could be validated by qPCR. Pathway analyses revealed over-representation of deregulated genes in the networks of proliferation, cell cycle, extracellular matrix biology, and inflammatory immune response. The Ki-67 mean change relative to baseline was -29.1% (P = 0.019) and -8.2% (P = 0.384) in the treatment and control arm, respectively. Between treatment groups, the change in Ki-67 was statistically significant (P = 0.029). Cleaved caspase-3 and CD34 expression were not significantly different between the celecoxib-treated and placebo-treated group. CONCLUSIONS: Short-term COX-2 inhibition by celecoxib induces transcriptional programs supporting an anti-tumour activity in primary breast cancer tissue. The impact on proliferation-associated genes is reflected by a reduction of Ki-67 positive cells. Therefore, COX-2 inhibition should be considered as treatment strategy for further clinical testing in primary breast cancer. Trial registration: ClinicalTrials.gov NCT01695226.
    Breast cancer research: BCR 04/2013; 15(2):R29. · 5.87 Impact Factor
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    ABSTRACT: We retrospectively compared the accuracy of two computer-aided detection (CAD) systems for the detection of malignant breast lesions on full-field digital mammograms. Mammograms of 326 patients were analyzed (117 patients with breast cancer, 209 negative cases), and each set of cases was read by two CAD systems (Second Look versus AccuDetect Galileo). True-positive fractions per image and case for soft densities, microcalcifications, and total cancers were assessed. Study results showed better overall performance of AccuDetect Galileo (when compared to Second Look) in detecting masses, microcalcifications, and all cancer types, especially in extremely dense breast parenchyma.
    Clinical imaging 03/2013; 37(2):283-8. · 0.73 Impact Factor
  • Cancer Research 12/2012; 72(24 Supplement):P5-01-13-P5-01-13. · 8.65 Impact Factor
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    ABSTRACT: BACKGROUND: To reduce mortality, women with a family history of breast cancer often start mammography screening at a younger age than the general population. Breast density is high in over 50% of women younger than 50 years. With high breast density, breast cancer incidence increases, but sensitivity of mammography decreases. Therefore, mammography might not be the optimal method for breast cancer screening in young women. Adding MRI increases sensitivity, but also the risk of false-positive results. The limitation of all previous MRI screening studies is that they do not contain a comparison group; all participants received both MRI and mammography. Therefore, we cannot empirically assess in which stage tumours would have been detected by either test.The aim of the Familial MRI Screening Study (FaMRIsc) is to compare the efficacy of MRI screening to mammography for women with a familial risk. Furthermore, we will assess the influence of breast density. METHODS: This Dutch multicentre, randomized controlled trial, with balanced randomisation (1:1) has a parallel grouped design. Women with a cumulative lifetime risk for breast cancer due to their family history of >=20%, aged 30--55 years are eligible. Identified BRCA1/2 mutation carriers or women with 50% risk of carrying a mutation are excluded. Group 1 receives yearly mammography and clinical breast examination (n = 1000), and group 2 yearly MRI and clinical breast examination, and mammography biennially (n = 1000).Primary endpoints are the number and stage of the detected breast cancers in each arm. Secondary endpoints are the number of false-positive results in both screening arms. Furthermore, sensitivity and positive predictive value of both screening strategies will be assessed. Cost-effectiveness of both strategies will be assessed. Analyses will also be performed with mammographic density as stratification factor. DISCUSSION: Personalized breast cancer screening might optimize mortality reduction with less over diagnosis. Breast density may be a key discriminator for selecting the optimal screening strategy for women < 55 years with familial breast cancer risk; mammography or MRI. These issues are addressed in the FaMRIsc study including high risk women due to a familial predisposition.Trial registrationNetherland Trial Register NTR2789.
    BMC Cancer 10/2012; 12(1):440. · 3.33 Impact Factor
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    ABSTRACT: Cowden syndrome (CS) is an autosomal dominant disorder characterized by presence of multiple hamartomas, and other benign and malignant abnormalities of the breasts, skin, thyroid, endometrium, gastrointestinal tract, and central nervous system. Hamartomas are benign, developmentally disorganized tumors that can develop in any of the above mentioned organs. The presence of massive calcifications in the breasts in very young women is an indication to perform a breast MRI to exclude a neoplasm since, like in the current case report, presence of breast calcifications may obscure a neoplasm. Although fibrocystic disease and cooccurrence of fibrocystic disease and breast cancer are much more common than CS, the presence of massive calcifications in the breasts of very young women should elicit the possibility of an underlying genetic disease. Furthermore, breast cancer and macrocephaly are considered major criteria for the diagnosis of CS and the combination of both is enough to establish the clinical diagnosis of this entity. Fibrocystic disease of the breasts and multinodular goiter are minor criteria. Family history is also important for the diagnosis of (any) hereditary disease.
    Case reports in radiology. 01/2012; 2012:638725.
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    ABSTRACT: Follow-up in oncology primarily encompasses medical technical examinations of patients following treatment for cancer. The term "aftercare" more accurately represents which approach should be taken after completion of cancer treatment: not only medical technical care, but fulfilment of care needs that result from the disease and its treatment. For each patient an individual aftercare plan should be put in place, which fulfils the 3 goals of aftercare: psycho-social and medical care, early diagnosis of recurrent disease or new primary disease activity if such early diagnosis bears clinical relevance, and medical audit. Involving patients in this decision-making process is generally limited in daily practice. The way in which the individual patient's aftercare is carried out, is still a scientific challenge. It is clear, however, that nothing about this is "standard".
    Nederlands tijdschrift voor geneeskunde 01/2011; 155(45):A4127.
  • EJC Supplements 03/2010; 8(3):207-207. · 2.71 Impact Factor
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    ABSTRACT: To determine the additional value of FDG-PET-CT as compared to conventional staging (CS) in high-risk breast cancer patients. Thirty-one high-risk breast cancer patients, 14 of whom had recurrent breast cancer, were included in this study, which took place between June 2005 and March 2008. None of the patients had clinical signs of distant metastases. FDG-PET-CT scanning was added to CS, which consisted of a chest x-ray, liver ultrasonography or CT, and bone scintigraphy. Median follow-up was 17 months (6-41 months). FDG-PET-CT was considered to have additional value to CS if it led to a change in treatment plan or if it made additional examinations to confirm or deny findings on CS unnecessary. FDG-PET-CT was considered to have additional value to CS in 13 patients (42% [95% CI: 23-61]). In five patients (16% [95% CI: 1-31]), FDG-PET-CT led to a change in treatment plan by identifying nodal metastases in the internal mammary chain (IMC; N = 3) or in the mediastinum (N = 2). In nine patients (29% [95% CI: 11-47]), FDG-PET-CT would have prevented the need for additional examinations; in seven of these nine patients, distant metastases were suggested in bone or liver on CS, but these did not show FDG uptake. FDG-PET-CT was found to have additional value to CS in 42% of the patients. To optimize cost-effectiveness, the main challenge now is to improve the selection of patients in whom FDG-PET-CT has additional value to CS.
    Acta oncologica (Stockholm, Sweden) 12/2009; 49(2):185-91. · 2.27 Impact Factor
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    ABSTRACT: Hand-held gamma-probes are used for the identification of the sentinel node location during intra-operative radio-guided surgeries. Various gamma-probes, which use different detectors, collimation and electronics, are available on the market. Spatial resolution, sensitivity and angular resolution of the probes are believed to be determinant for the success of the identification of the sentinel node during radiosurgery. We compared the above-mentioned performances of sentinel probes from six manufacturers available in the European market by means of the NEMA NU3-2004 standard, which allows the users to evaluate the probes during a situation which mimics a intra-operative radio-guided surgery. This study presents a summary of characteristics to be expected when using the tested gamma-probes during intra-operative radio-guided surgeries, with particular emphasis on breast cancer sentinel node surgery. The results from this study can be used as the guidance for the selection of a sentinel lymph node probe.
    Nuclear Medicine Communications 11/2009; 30(11):854-61. · 1.38 Impact Factor
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    ABSTRACT: To determine the difference in size between computed tomography (CT)-based irradiated boost volumes and simulator-based irradiated volumes in patients treated with breast-conserving therapy and to analyze whether the use of anisotropic three-dimensional clinical target volume (CTV) margins using the histologically determined free resection margins allows for a significant reduction of the CT-based boost volumes. The CT data from 49 patients were used to delineate a planning target volume (PTV) with isotropic CTV margins and to delineate a PTV(sim) that mimicked the PTV as delineated in the era of conventional simulation. For 17 patients, a PTV with anisotropic CTV margins was defined by applying customized three-dimensional CTV margins, according to the free excision margins in six directions. Boost treatment plans consisted of conformal portals for the CT-based PTVs and rectangular fields for the PTV(sim). The irradiated volume (volume receiving > or =95% of the prescribed dose [V(95)]) for the PTV with isotropic CTV margins was 1.6 times greater than that for the PTV(sim): 228 cm(3) vs. 147 cm(3) (p < .001). For the 17 patients with a PTV with anisotropic CTV margins, the V(95) was similar to the V(95) for the PTV(sim) (190 cm(3) vs. 162 cm(3); p = NS). The main determinant for the irradiated volume was the size of the excision cavity (p < .001), which was mainly related to the interval between surgery and the planning CT scan (p = .029). CT-based PTVs with isotropic margins for the CTV yield much greater irradiated volumes than fluoroscopically based PTVs. Applying individualized anisotropic CTV margins allowed for a significant reduction of the irradiated boost volume.
    International journal of radiation oncology, biology, physics 04/2009; 75(3):757-63. · 4.59 Impact Factor
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    The Breast Journal 01/2008; 14(2):199-200. · 1.83 Impact Factor
  • Ejc Supplements - EJC SUPPL. 01/2008; 6(7):216-216.
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    ABSTRACT: Follow-up after curative treatment for breast cancer consists of frequent outpatient clinic visits, scheduled at regular intervals. Its aim is primarily to detect local disease recurrence, or a second primary breast cancer, but also to provide information and psychosocial support. The cost-effectiveness of these frequent visits is being questioned however, leading to a search for less intensive follow-up strategies, such as follow-up by the general practitioner, patient-initiated or nurse-led follow-up or contact by telephone. These strategies are generally considered to be safe, but they are not yet widely accepted in clinical practice. Since brief interventions based on self-education and information have been shown to be able to improve quality of life, we hypothesise that these interventions may lead to a better acceptance of reduced follow-up by both patients and professionals.
    European Journal of Cancer 04/2007; 43(4):647-53. · 5.06 Impact Factor
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    ABSTRACT: After curative treatment for breast cancer women frequently attend scheduled follow-up examinations. Usually the follow-up is most frequent in the first 2-3 years (2-4 times a year); thereafter the frequency is reduced to once a year in most countries. Its main aim is to detect local disease recurrence, or a second primary breast cancer, but also to provide information and psychosocial support. However, the cost-effectiveness of these frequent visits is under much debate, leading to a search for less intensive and more cost-effective follow-up strategies. In this paper the design of the MaCare trial is described. This trial compares the cost-effectiveness of four follow-up strategies for curatively treated breast cancer patients. We investigate the costs and effects of nurse-led telephone follow-up and a short educational group programme. The MaCare trial is a multi centre randomised clinical trial in which 320 breast cancer patients are randomised into four follow-up strategies, focussed on the first 18 months after treatment: 1) standard follow-up; 2) nurse-led telephone follow-up; 3) arm 1 with the educational group programme; 4) arm 2 with the educational group programme. Data is collected at baseline and 3, 6, 12 and 18 months after treatment. The primary endpoint of the trial is cancer-specific quality of life as measured by the global health/QoL scale of the EORTC QLQ-C30. Secondary outcomes are perceived feelings of control, anxiety, patients' satisfaction with follow-up and costs. A cost-effectiveness analysis will be performed from a societal perspective. Reduced follow-up strategies for breast cancer have not yet been widely applied in clinical practice. Improvement of psychosocial support and information to patients could lead to a better acceptance of reduced follow-up. The MaCare trial combines a reduced follow-up strategy with additional psychosocial support. Less frequent follow-up can reduce the burden on medical specialists and costs. The educational group programme can improve QoL of patients, but also less frequent follow-up can improve QoL by reducing the anxiety experienced for each follow-up visit. Results of the trial will provide knowledge on both costs and psychosocial aspects regarding follow-up and are expected in 2009.
    BMC Cancer 02/2007; 7:1. · 3.33 Impact Factor
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    ABSTRACT: Abstract Background After curative treatment for breast cancer women frequently attend scheduled follow-up examinations. Usually the follow-up is most frequent in the first 2–3 years (2–4 times a year); thereafter the frequency is reduced to once a year in most countries. Its main aim is to detect local disease recurrence, or a second primary breast cancer, but also to provide information and psychosocial support. However, the cost-effectiveness of these frequent visits is under much debate, leading to a search for less intensive and more cost-effective follow-up strategies. In this paper the design of the MaCare trial is described. This trial compares the cost-effectiveness of four follow-up strategies for curatively treated breast cancer patients. We investigate the costs and effects of nurse-led telephone follow-up and a short educational group programme. Methods/design The MaCare trial is a multi centre randomised clinical trial in which 320 breast cancer patients are randomised into four follow-up strategies, focussed on the first 18 months after treatment: 1) standard follow-up; 2) nurse-led telephone follow-up; 3) arm 1 with the educational group programme; 4) arm 2 with the educational group programme. Data is collected at baseline and 3, 6, 12 and 18 months after treatment. The primary endpoint of the trial is cancer-specific quality of life as measured by the global health/QoL scale of the EORTC QLQ-C30. Secondary outcomes are perceived feelings of control, anxiety, patients' satisfaction with follow-up and costs. A cost-effectiveness analysis will be performed from a societal perspective. Discussion Reduced follow-up strategies for breast cancer have not yet been widely applied in clinical practice. Improvement of psychosocial support and information to patients could lead to a better acceptance of reduced follow-up. The MaCare trial combines a reduced follow-up strategy with additional psychosocial support. Less frequent follow-up can reduce the burden on medical specialists and costs. The educational group programme can improve QoL of patients, but also less frequent follow-up can improve QoL by reducing the anxiety experienced for each follow-up visit. Results of the trial will provide knowledge on both costs and psychosocial aspects regarding follow-up and are expected in 2009.
    BMC Cancer 01/2007; · 3.33 Impact Factor

Publication Stats

84 Citations
47.20 Total Impact Points

Institutions

  • 2007–2014
    • Maastricht Universitair Medisch Centrum
      • Central Diagnostic Laboratory
      Maestricht, Limburg, Netherlands
  • 2012
    • Academic Medical Center (AMC)
      Amsterdamo, North Holland, Netherlands
  • 2009
    • Maastro Clinic
      Maestricht, Limburg, Netherlands