A. Timmermans
University of Amsterdam
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by A. Timmermans.
Maturitas | 2011
N. van Hanegem; M. C. Breijer; Khalid S. Khan; Tj Clark; M.P.M. Burger; B.W. Mol; A. Timmermans
Postmenopausal bleeding (PMB) is a common complaint in general gynecological practice. Women with PMB have around a 10% chance of having endometrial carcinoma and therefore PMB always needs further evaluation. This article summarizes the reviews on the subject and provides an overview of the use of diagnostic tools in patients with PMB. Four types of diagnostic test are described: sonographic measurement of endometrial thickness, endometrial sampling, hysteroscopy and saline infusion sonography. All four have been independently shown to be accurate in excluding endometrial cancer. However, neither in systematic reviews nor in international guidelines is consensus found regarding the sequence in which these methods should be employed in women with PMB. For measurement of endometrial thickness in symptomatic women, a cut-off value of 3mm is recommended, but the cost-effectiveness of this strategy has yet to be shown. Research should now focus on the incorporation of individual patient characteristics and pre-test probabilities for cancer in algorithms for the investigation of PMB, and the most cost-effective sequenced combination of the four types of test.
Ultrasound in Obstetrics & Gynecology | 2012
M. C. Breijer; J. A. H. Peeters; Brent C. Opmeer; T. J. Clark; R. H. M. Verheijen; B.W. Mol; A. Timmermans
Measurement of endometrial thickness is an important tool in the assessment of women with postmenopausal bleeding, but the role of endometrial thickness measurement by ultrasound in asymptomatic women is unclear. The aims of this study were to determine: (1) the normal endometrial thickness measured by ultrasonography, (2) the prevalence of serious endometrial pathology and (3) the sensitivity and specificity of endometrial thickness measurement by transvaginal ultrasonography (TVS) for diagnosing premalignant and malignant endometrial disease in asymptomatic postmenopausal women.
Obstetrics and Gynecology International | 2010
M. C. Breijer; A. Timmermans; H. C. van Doorn; Bwj Mol; Brent C. Opmeer
Postmenopausal bleeding (PMB) is a common clinical problem. Patients with PMB have 10%–15% chance of having endometrial carcinoma and therefore the diagnostic workup is aimed at excluding malignancy. Patient characteristics can alter the probability of having endometrial carcinoma in patients with PMB; in certain groups of patients the incidence has been reported to be as high as 29%. Transvaginal sonography (TVS) is used as a first step in the diagnostic workup, but different authors have come to different conclusions assessing the accuracy of TVS for excluding endometrial carcinoma. Diagnostic procedures obtaining material for histological assessment (e.g., dilatation and curettage, hysteroscopy, and endometrial biopsy) can be more accurate but are also more invasive. The best diagnostic strategy for diagnosing endometrial carcinoma in patients with PMB still remains controversial. Future research should be focussed on achieving a higher accuracy of different diagnostic strategies.
Journal of Minimally Invasive Gynecology | 2012
T.C. van Kerkvoorde; Sebastiaan Veersema; A. Timmermans
STUDY OBJECTIVEnTo estimate the long-term complication rate of office hysteroscopy with the vaginoscopic approach.nnnDESIGNnRetrospective cohort study (Canadian Task Force classification II-A).nnnSETTINGnUniversity-affiliated teaching hospital with outpatient hysteroscopy facilities.nnnPATIENTSnBetween January 2005 and October 2007, all consecutive patients undergoing office hysteroscopy with the vaginoscopic approach were analyzed, 1028 procedures in total.nnnINTERVENTIONSnTherapeutic or diagnostic office hysteroscopy with the vaginoscopic approach. The complication registration of the gynecology department and a random sample of one third of the medical records were analyzed for long-term complications.nnnMEASUREMENTS AND MAIN RESULTSnOf the 1028 hysteroscopic procedures, 622 (60%) were diagnostic, 328 (32%) were therapeutic hysteroscopic procedures, and 78 (8%) procedures failed. In the complication registration and in the medical charts, 1 significant complication could be identified.nnnCONCLUSIONSnOffice hysteroscopy with the vaginoscopic approach is a safe procedure. This study showed an extremely low risk of long-term complications.
British Journal of Obstetrics and Gynaecology | 2009
A. Timmermans; Sebastiaan Veersema; T. C. van Kerkvoorde; L. F. van der Voet; Brent C. Opmeer; Marlies Y. Bongers; B.W. Mol
We describe the design of a randomised controlled trial to evaluate the efficacy of endometrial polyp removal in women with postmenopausal bleeding. We designed a trial in which patients with postmenopausal bleeding and endometrial thickness >4u2003mm undergo hysteroscopy. If during hysteroscopy an endometrial polyp was diagnosed, patients were asked to participate in this trial and after informed consent allocated to immediate removal of the polyp or expectant management. This trial suffered from lack of recruitment related both to doctors seeking for informed consent as well as to patients’ unwillingness to participate in this trial. However, a randomised controlled trial on this subject is still necessary to evaluate the efficacy of uterine cavity evaluation in the diagnostic work‐up of women with postmenopausal bleeding, focussing on benign pathology. Therefore, we propose an alternative design, which might be more feasible.
American Journal of Hypertension | 2015
Yentl C. Haan; Inge Oudman; Maria E. de Lange; A. Timmermans; Willem M. Ankum; Gert A. van Montfrans; Lizzy M. Brewster
BACKGROUNDnFemale-specific risk factors for cardiovascular disease are understudied. We assessed whether women with uterine fibroids have a greater hypertension risk, independent of the shared risk factors for both conditions.nnnMETHODSnBlood pressure was measured in women scheduled for fibroid surgery compared to women scheduled for nonfibroid gynecological surgery and women randomly sampled from the general population. We used multivariable binary logistic regression to assess whether hypertension was more common with surgically treated fibroids, independent of age, body mass index, and African ancestry.nnnRESULTSnWe included 1,342 women (542 of African ancestry), of which 272 scheduled for fibroid surgery, 385 controls scheduled for nonfibroid gynecological surgery, and 685 random population controls, with a mean age (SD) of, respectively, 43.4 (6.6), 41.3 (10.2), and 45.1 (6.6) years; and a mean body mass index (SD) of, respectively, 27.4 (5.3), 25.7 (5.7), and 28.2 (5.6) kg/m(2). Hypertension was found more frequently with surgically treated fibroids, with an occurrence of 41.9% in women with fibroids vs. 27.5% in surgical controls, and 28.3% in population controls (P < 0.001 for fibroids vs. controls). The association with hypertension was independent of age, body mass index, and African ancestry (odds ratio, 2.4; 95% confidence interval, 1.7-3.4).nnnCONCLUSIONSnHypertension risk is higher in Dutch women with surgically treated fibroids than in surgery or population controls, independent of age, body mass index, and African ancestry. Our data add to the body of evidence indicating that women with uterine fibroids are eligible for hypertension screening.
British Journal of Obstetrics and Gynaecology | 2017
N. van Hanegem; M. C. Breijer; S. A. Slockers; Mohammad Hadi Zafarmand; Pm Geomini; R. Catshoek; J.M.A. Pijnenborg; L. F. van der Voet; F. P H L J Dijkhuizen; G. C R van Hoecke; N. Reesink-Peters; Sebastiaan Veersema; M. H. A. van Hooff; P. J. M. van Kesteren; Judith A.F. Huirne; Brent C. Opmeer; Marlies Y. Bongers; B.W. Mol; A. Timmermans
To evaluate the effectiveness of hysteroscopy for the detection and treatment of endometrial polyps versus expectant management in women with postmenopausal bleeding (PMB), a thickened endometrium and benign endometrial sampling.
British Journal of Obstetrics and Gynaecology | 2017
I. M. A. Reinders; Pm Geomini; A. Timmermans; M. E. de lange; Marlies Y. Bongers
Endometrial ablation has been widely implemented in the outpatient setting. Many different protocols of local anaesthesia during endometrial ablation are used and described. However, prospective studies to assess and evaluate these protocols appear to be scarce.
International Journal of Surgical Oncology | 2016
M. C. Breijer; Nicole C.M. Visser; N. van Hanegem; A. A. van der Wurff; Brent C. Opmeer; H. C. van Doorn; Ben Willem J. Mol; J.M.A. Pijnenborg; A. Timmermans
Objective. To determine whether structured assessment of outpatient endometrial biopsies decreases the number of inconclusive samples. Design. Retrospective cohort study. Setting. Single hospital pathology laboratory. Population. Endometrial biopsy samples of 66 women with postmenopausal bleeding, collected during the usual diagnostic work-up and assessed as insufficient for a reliable histological diagnosis. Methods. Endometrial biopsy samples were requested from the pathology laboratories. The retrieved samples were systematically reassessed by a single pathologist specialized in gynecology. Main Outcome Measure. Disagreement between initial assessment and conclusion after structured reassessment. Results. We retrieved 36 of 66 endometrial biopsy samples from six different pathology laboratories. Structured reassessment of the retrieved samples by a single pathologist specialized in gynecology did not change the conclusion in 35 of the 36 samples. The remaining sample contained a large amount of endometrial tissue and the diagnosis at reassessment was endometrial hyperplasia without atypia. All other samples contained insufficient material for a reliable diagnosis. Conclusion. A structured reassessment of endometrial biopsies samples, which were classified as inconclusive due to insufficient material, did not change the conclusion. Although it might be helpful for pathologists to have diagnostic criteria for adequacy and/or inadequacy of an endometrial biopsy sample, the gain in efficiency is likely to be small.
The Scientific World Journal | 2015
Maria Breijer; N. van Hanegem; Nicole C.M. Visser; Rhm Verheijen; Ben Willem J. Mol; Johanna M.A. Pijnenborg; Brent C. Opmeer; A. Timmermans
Objective. To evaluate whether a model to predict a failed endometrial biopsy in women with postmenopausal bleeding (PMB) and a thickened endometrium can reduce costs without compromising diagnostic accuracy. Design, Setting, and Population. Model based cost-minimization analysis. Methods. A decision analytic model was designed to compare two diagnostic strategies for women with PMB: (I) attempting office endometrial biopsy and performing outpatient hysteroscopy after failed biopsy and (II) predicted probability of a failed endometrial biopsy based on patient characteristics to guide the decision for endometrial biopsy or immediate hysteroscopy. Robustness of assumptions regarding costs was evaluated in sensitivity analyses. Main Outcome Measures. Costs for the different strategies. Results. At different cut-offs for the predicted probability of failure of an endometrial biopsy, strategy I was generally less expensive than strategy II. The costs for strategy I were always € 460; the costs for strategy II varied between € 457 and € 475. At a 65% cut-off, a possible saving of € 3 per woman could be achieved. Conclusions. Individualizing the decision to perform an endometrial biopsy or immediate hysteroscopy in women presenting with postmenopausal bleeding based on patient characteristics does not increase the efficiency of the diagnostic work-up.