M Boers

VU medisch centrum, Amsterdam, North Holland, Netherlands

Are you M Boers?

Claim your profile

Publications (7)25.12 Total impact

  • Article: Hexokinase III, cyclin A and galectin-3 are overexpressed in malignant follicular thyroid nodules.
    [show abstract] [hide abstract]
    ABSTRACT: Distinguishing malignant thyroid nodules in patients with follicular cytology by fine-needle aspiration (FNA) remains problematic. The large majority of thyroid nodules (> 85%) are overtreated. Therefore, a clear need exists to develop more accurate initial diagnostic tests for follicular thyroid nodules. Galectin-3 is the most recent promising marker to aid discrimination between benign and malignant thyroid lesions; however, this biomarker can be absent in follicular malignancies. This study was undertaken to determine whether additional biomarkers can help to discriminate between benign and malignant thyroid nodules. Surgical specimens of 36 patients with benign (n = 12) and malignant (n = 24) thyroid nodules showing follicular cytology were assessed by immunohistochemistry for the expression of galectin-3 and novel biomarkers. Expression of hexokinase III (HK III) (P = 0.000) cyclin A (P = 0.002) and galectin-3 (P = 0.003) differed significantly between benign and malignant thyroid nodules. HK III had a sensitivity of 79% [95% confidence interval (CI) 60-91] and a specificity of 100% (95% CI 76-100) in predicting malignancy. Galectin-3 had a sensitivity of 79% (95% CI 56-91) and a specificity of 75% (95% CI 47-91) in predicting malignancy. Combining HK III, cyclin A and galectin-3 in a parallel test increased the sensitivity to 96% (95% CI 80-99) while the specificity remained at a high level of 75% (95% CI 47-91). Leave-one-out cross-validation demonstrated a stable predictive validity of a model based on HK III, cyclin A and galectin-3. In this study, we have demonstrated that in addition to galectin-3, HK III and cyclin A profiles could be important biomarkers in predicting malignancy in follicular thyroid nodules. The use of these biomarkers may allow an accurate preoperative diagnosis of thyroid cancer, which can be cost saving and may avoid serious morbidity such as vocal cord paralysis. The value of the suggested biomarkers warrants further evaluation in a large prospective study on cytological samples of follicular thyroid nodules.
    Clinical Endocrinology 02/2008; 68(2):252-7. · 3.17 Impact Factor
  • Article: Fluorine-18 fluorodeoxyglucose positron emission tomography (PET) to detect vital retinoblastoma in the eye: preliminary experience.
    [show abstract] [hide abstract]
    ABSTRACT: To report our first experience with FDG-PET in the detection of vital retinoblastoma. Four newly diagnosed retinoblastoma patients, two treated retinoblastoma patients, and four control patients were enrolled in this pilot study. F18-FDG uptake was assessed in the light of clinical and histopathological features. PET discriminated between new patients and controls, although tumor uptake varied widely. PET added no useful information with regard to possible vital tissue in tumor scars in the eye of the two treated retinoblastoma patients. Moreover, PET findings did not correlate with clinical or histopathological features. Based on this small pilot study, F18-PET shows little promise in the detection of retinoblastoma. More research on other radiofarmacons is recommended.
    Ophthalmic Genetics 04/2004; 25(1):31-5. · 0.93 Impact Factor
  • Article: Reproducibility and clinical value of 18F-fluorodeoxyglucose positron emission tomography in recurrent melanoma.
    [show abstract] [hide abstract]
    ABSTRACT: The purpose of this study was to assess the reproducibility and clinical impact of positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) in patients with (suspected) recurrent melanoma. The clinical value of PET was prospectively measured in 58 consecutive patients referred for PET because of unresolved clinical questions after conventional work-up. Diagnostic understanding and therapy choice by referring physicians were evaluated before, directly after, and 6 months after PET. Observer agreement of PET readings was measured with respect to various parameters (interpretation, number and localization of lesions, 'clinically decisive' metastases), using intra-class correlation coefficients. FDG PET improved diagnostic understanding in 33 cases (57%). In six patients (10%), diagnostic understanding was solely based on PET information. According to the attending clinicians, PET contributed to a positive change of planned treatment in 23 patients (40%) and increased confidence in the chosen treatment in 23 (40%). Observer agreement of PET readings was very high (intra-class correlation coefficients were between 0.87 and 0.94). The diagnostic value related especially to the whole-body scan technique and the superior specificity, compared to conventional work-up. It is concluded that, in problematical cases with (suspected) recurrent melanoma, 18F-FDG PET had considerable impact on diagnostic understanding and management. Together with the excellent observer reliability, these results justify further studies to determine the optimal place of PET in routine diagnostic algorithms in recurrent melanoma.
    Nuclear Medicine Communications 06/2002; 23(5):475-81. · 1.40 Impact Factor
  • Source
    Article: Diagnostic accuracy of 18F-fluorodeoxyglucose positron emission tomography in the follow-up of papillary or follicular thyroid cancer.
    [show abstract] [hide abstract]
    ABSTRACT: Positron emission tomography with 18F-fluorodeoxyglucose is a relatively new nuclear imaging technique in oncology. We conducted a systematic review to determine the diagnostic accuracy of 18F-fluorodeoxyglucose positron emission tomography in patients suspected of recurrent papillary or follicular thyroid carcinoma. Two reviewers independently selected, extracted, and assessed data from relevant literature found in computerized databases and by reference tracking. Prospective and retrospective studies with 10 human subjects, or more, that evaluated the accuracy of ring positron emission tomography, using 18F-fluorodeoxyglucose in follicular and papillary thyroid cancer, were included. Studies on 18F-fluorodeoxyglucose imaging using gamma cameras, reviews, case reports, editorials, letters, and comments were excluded. The methodological quality was assessed by applying the criteria for diagnostic tests recommended by the Cochrane Methods Group on Screening and Diagnostic Tests. A rating system was used for qualitative analysis consisting of four levels of evidence (1 = highest level; 4 = lowest level). Fourteen studies met the inclusion criteria. All studies claimed a positive role for positron emission tomography but, at evidence levels 3 or 4, precluding quantitative analysis. Methodological problems included poor validity of reference tests and a lack of blinding of test performance and interpretation. The reviewed material was heterogeneous with respect to patient variation and validation methodology. The most consistent data were found on the ability of 18F-fluorodeoxyglucose positron emission tomography to provide an anatomical substrate in patients with elevated serum Tg and negative iodine-131 scans. In conclusion, the results seem to support the potential of 18F-fluorodeoxyglucose positron emission tomography to identify and localize foci of recurrent cancer in the latter patient subset. However, implementation of positron emission tomography in a routine diagnostic algorithm requires additional evidence.
    Journal of Clinical Endocrinology &amp Metabolism 09/2001; 86(8):3779-86. · 6.50 Impact Factor
  • Article: Second primary tumors in hereditary retinoblastoma: a register-based study, 1945-1997: is there an age effect on radiation-related risk?
    [show abstract] [hide abstract]
    ABSTRACT: The aim of this study is to evaluate the influence of age at external beam irradiation (EBRT) on the occurrence of second primary tumors (SPTs) inside and outside the irradiation field in hereditary retinoblastoma patients. Cross-sectional study. The study included 263 hereditary retinoblastoma patients born in The Netherlands between 1945 and 1997. A national register-based follow-up cohort study was performed on hereditary retinoblastoma patients. Information on therapy, age at irradiation, and location of SPT was obtained from the register. The Kaplan-Meier method calculated cumulative incidences of SPT in three subgroups: irradiation before (early EBRT) and after 12 months of age (late EBRT), and no irradiation. The Mantel-Cox method determined the statistical significance of differences between the cumulative incidence curves. Development of SPT inside and outside a precisely defined irradiation field in relation to age at irradiation. Our definition excluded pineoblastoma as SPT, because they constitute part of a trilateral retinoblastoma; in addition, they lie outside the field of irradiation. The cumulative incidence of SPT at the age of 25 years was 22% (95% confidence intervals 13%-34%) in the early EBRT group, 3% (0%-14%) in the late EBRT group, and 5% (1%-16%) in the nonirradiated group (Mantel-Cox overall: P = 0.001; between early and late EBRT, P = 0.04). However, in early irradiated patients, the incidence of SPTs inside and outside the irradiation field was similar (11%), and the difference between early and late EBRT in incidence of SPT inside the field of irradiation was less prominent than overall (11% vs. 3%: P = 0.37). Sensitivity analysis showed the results depended on the way SPT, irradiation field, and, especially, pineoblastomas are defined. Hereditary retinoblastoma confers an increased risk for the development of SPT, especially in patients treated with EBRT before the age of 12 months. However, the presence of similar numbers of SPTs inside and outside the irradiation field suggests that irradiation is not the cause. In other words, this study does not show an age effect on radiation-related risk. Rather, early EBRT is probably a marker for other risk factors of SPT.
    Ophthalmology 07/2001; 108(6):1109-14. · 5.45 Impact Factor
  • Article: At what age could screening for familial retinoblastoma be stopped? A register based study 1945-98.
    [show abstract] [hide abstract]
    ABSTRACT: To evaluate until what age children in families with retinoblastoma should be screened. A register based cohort (n= 685) study of Dutch retinoblastoma patients (1945-1998). The records of all familial hereditary retinoblastoma patients from 1945 were reviewed and the age at diagnosis and either they were screened from birth determined. 75 patients had the familial hereditary form of retinoblastoma. The mean age at diagnosis in patients with fundus screening (n=50) from birth on was 4.9 months (median 1.9 months; range 1 day to 48 months). Thus, 4 years was the latest onset of familial retinoblastoma properly evaluated from birth. This mean age was significantly different (p<0.0001) from the mean age at diagnosis in patients without fundus screening (n=25) from birth (mean 17.2 months; median 10.0 months; range 1.5-63.0 months). Ophthalmological screening of children and sibs at risk for familial hereditary retinoblastoma is recommended until the age of 4 years in order to detect retinoblastoma as early as possible.
    British Journal of Ophthalmology 11/2000; 84(10):1170-2. · 2.90 Impact Factor
  • Article: Trilateral retinoblastoma: is the location of the intracranial tumor important?
    Cancer 03/2000; 88(4):965-7. · 4.77 Impact Factor