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Dive into the research topics where Parvin Tajik is active.

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Featured researches published by Parvin Tajik.


European Journal of Cancer | 2013

Which patients benefit most from primary surgery or neoadjuvant chemotherapy in stage IIIC or IV ovarian cancer? An exploratory analysis of the European Organisation for Research and Treatment of Cancer 55971 randomised trial

Hannah S. van Meurs; Parvin Tajik; Michel H.P. Hof; Ignace Vergote; Gemma G. Kenter; Ben Willem J. Mol; Marrije R. Buist; Patrick M. Bossuyt

BACKGROUND To investigate whether biomarkers consisting of baseline characteristics of advanced stage ovarian cancer patients can help in identifying subgroups of patients who would benefit more from primary surgery or neoadjuvant chemotherapy. METHODS We used data of the European Organisation for Research and Treatment of Cancer (EORTC) 55971 trial in which 670 patients were randomly assigned to primary surgery or neoadjuvant chemotherapy. The primary outcome was overall survival. Ten baseline clinical and pathological characteristics were selected as potential biomarkers. Using Subpopulation Treatment Effect Pattern Plots (STEPP), biomarkers with a statistically significant qualitative additive interaction with treatment were considered as potentially informative for treatment selection. We also combined selected biomarkers to form a multimarker treatment selection rule. FINDINGS The size of the largest metastatic tumour and clinical stage were significantly associated with the magnitude of the benefit from treatment, in terms of five-year survival (p for interaction: 0.008 and 0.016, respectively). Stage IIIC patients with metastatic tumours ⩽45 mm benefited more from primary surgery while stage IV patients with metastatic tumours >45 mm benefited more from neoadjuvant chemotherapy. In stage IIIC patients with larger metastatic tumours and in stage IV patients with less extensive metastatic tumours both treatments were equally effective. We estimated that by selecting treatments for patients based on largest metastatic tumour and clinical stage, the potential five-year survival rate in the population of treated patients would be 27.3% (95% confidence interval (CI) 21.9-33.0), 7.8% higher than if all were treated with primary surgery, and 5.6% higher if all were treated with neoadjuvant chemotherapy. INTERPRETATION Although survival was comparable after primary surgery and neoadjuvant chemotherapy in the overall group of patients with ovarian cancer in the EORTC 55971 trial, we found in this exploratory analysis that patients with stage IIIC and less extensive metastatic tumours had higher survival with primary surgery, while patients with stage IV disease and large metastatic tumours had higher survival with neoadjuvant chemotherapy. For patients who did not meet these criteria, both treatment options led to comparable survival rates.


Clinical Cancer Research | 2013

Trial Designs for Personalizing Cancer Care: A Systematic Review and Classification

Parvin Tajik; Aleiko H. Zwinderman; Ben W. J. Mol; Patrick M. Bossuyt

There is an increasing interest in the evaluation of prognostic and predictive biomarkers for personalizing cancer care. The literature on the trial designs for evaluation of these markers is diverse and there is no consensus in the classification or nomenclature. We set this study to review the literature systematically, to identify the proposed trial designs, and to develop a classification scheme. We searched MEDLINE, EMBASE, Cochrane Methodology Register, and MathSciNet up to January 2013 for articles describing these trial designs. In each eligible article, we identified the trial designs presented and extracted the term used for labeling the design, components of patient flow (marker status of eligible participants, intervention, and comparator), study questions, and analysis plan. Our search strategy resulted in 88 eligible articles, wherein 315 labels had been used by authors in presenting trial designs; 134 of these were unique. By analyzing patient flow components, we could classify the 134 unique design labels into four basic patient flow categories, which we labeled with the most frequently used term: single-arm, enrichment, randomize-all, and biomarker-strategy designs. A fifth category consists of combinations of the other four patient flow categories. Our review showed that a considerable number of labels has been proposed for trial designs evaluating prognostic and predictive biomarkers which, based on patient flow elements, can be classified into five basic categories. The classification system proposed here could help clinicians and researchers in designing and interpreting trials evaluating predictive biomarkers, and could reduce confusion in labeling and reporting. Clin Cancer Res; 19(17); 4578–88. ©2013 AACR.


British Journal of Obstetrics and Gynaecology | 2012

Should cervical favourability play a role in the decision for labour induction in gestational hypertension or mild pre-eclampsia at term? An exploratory analysis of the HYPITAT trial

Parvin Tajik; K. van der Tuuk; Corine M. Koopmans; Hendricus Groen; M.G. van Pampus; Pp van der Berg; J.A. van der Post; Aj van Loon; Cjm de Groot; Anneke Kwee; Ajm Huisjes; E. J. R. Van Beek; D.N. Papatsonis; K.W. Bloemenkamp; G.A. van Unnik; Martina Porath; R.J. Rijnders; R.H. Stigter; K. de Boer; H.C. Scheepers; Aeilko H. Zwinderman; P. M. M. Bossuyt; B.W. Mol

Please cite this paper as: Tajik P, van der Tuuk K, Koopmans C, Groen H, van Pampus M, van der Berg P, van der Post J, van Loon A, de Groot C, Kwee A, Huisjes A, van Beek E, Papatsonis D, Bloemenkamp K, van Unnik G, Porath M, Rijnders R, Stigter R, de Boer K, Scheepers H, Zwinderman A, Bossuyt P, Mol B. Should cervical favourability play a role in the decision for labour induction in gestational hypertension or mild pre‐eclampsia at term? An exploratory analysis of the HYPITAT trial. BJOG 2012;119:1123–1130.


Human Genetics | 2011

Genomic markers to tailor treatments: waiting or initiating?

Parvin Tajik; Patrick M. Bossuyt

The decade since the publication of the Human Genome Project draft has ended with the discovery of hundreds of genomic markers related to diseases and phenotypes. However, the project has not yet delivered on its promise to tailor treatments for individuals. The number of genomic markers in clinical practice is very small. The number of markers to guide treatment decisions is even smaller. In order to speed up discovery and validation of genomic treatment selection markers, we call for considering the brilliant potential of randomized clinical trials. If biomedical research community can collaborate in organizing large-scale consortium of clinical trials associated with well-designed biobanks, these studies would soon act as huge laboratories for investigating genomic medicine; a big step forward towards personalizing medicine.


British Journal of Obstetrics and Gynaecology | 2014

Using vaginal Group B Streptococcus colonisation in women with preterm premature rupture of membranes to guide the decision for immediate delivery: a secondary analysis of the PPROMEXIL trials

Parvin Tajik; D.P. van der Ham; Mohammad Hadi Zafarmand; Michel H.P. Hof; Jonathan M. Morris; Maureen Franssen; C.J.M. de Groot; Johannes J. Duvekot; Martijn A. Oudijk; Christine Willekes; K.W. Bloemenkamp; Martina Porath; Mallory Woiski; Bettina M.C. Akerboom; J. M. Sikkema; B. Nij Bijvank; Antonius L.M. Mulder; P. M. M. Bossuyt; B. W. J. Mol

To investigate whether vaginal Group B Streptococcus (GBS) colonisation or other baseline characteristics of women with preterm premature rupture of membranes (PPROM) can help in identifying subgroups of women who would benefit from immediate delivery.


British Journal of Obstetrics and Gynaecology | 2016

Caesarean section rates and adverse neonatal outcomes after induction of labour versus expectant management in women with an unripe cervix: a secondary analysis of the HYPITAT and DIGITAT trials

Thomas Bernardes; K. Broekhuijsen; C. M. Koopmans; Kim Boers; L. van Wyk; Parvin Tajik; M.G. van Pampus; Sicco A. Scherjon; B.W. Mol; Maureen Franssen; van den Paul Berg; Henk Groen

To evaluate caesarean section and adverse neonatal outcome rates after induction of labour or expectant management in women with an unripe cervix at or near term.


The Lancet | 2013

SYNTAX score II

Parvin Tajik; Katrien Oude Rengerink; Ben Willem J. Mol; Patrick M. Bossuyt

1 Farooq V, van Klaveren D, Steyerberg EW, et al. Anatomical and clinical characteristics to guide decision making between coronary artery bypass surgery and percutaneous coronary intervention for individual patients: development and validation of SYNTAX score II. Lancet 2013; 381: 639–50. 2 Janes H, Pepe MS, Bossuyt PM, Barlow WE. Measuring the performance of markers for guiding treatment decisions. Ann Intern Med 2011; 154: 253–59. 3 Huang Y, Gilbert PB, Janes H. Assessing treatment-selection markers using a potential outcomes framework. Biometrics 2012; 68: 687–96. 4 Song X, Pepe MS. Evaluating markers for selecting a patient’s treatment. Biometrics 2004; 60: 874–83. SYNTAX score II


Ultrasound in Obstetrics & Gynecology | 2016

A multivariable model to guide the decision for pessary placement to prevent preterm birth in women with a multiple pregnancy: a secondary analysis of the ProTWIN trial.

Parvin Tajik; M. Monfrance; J. van ‘t Hooft; Sophie Liem; Ewoud Schuit; K.W. Bloemenkamp; Johannes J. Duvekot; B. Nij Bijvank; Maureen Franssen; Martijn A. Oudijk; H. C. J. Scheepers; J. M. Sikkema; Mallory Woiski; B.W. Mol; Dick J. Bekedam; P. M. M. Bossuyt; Mohammad Hadi Zafarmand

The ProTWIN Trial (NTR1858) showed that, in women with a multiple pregnancy and a cervical length < 25th percentile (38 mm), prophylactic use of a cervical pessary reduced the risk of adverse perinatal outcome. We investigated whether other maternal or pregnancy characteristics collected at baseline can improve identification of women most likely to benefit from pessary placement.


European Journal of Obstetrics & Gynecology and Reproductive Biology | 2015

Relevance of individual participant data meta-analysis for studies in obstetrics: delivery versus expectant monitoring for hypertensive disorders of pregnancy

Kim Broekhuijsen; Thomas Bernardes; Gert-Jan van Baaren; Parvin Tajik; Natalia Novikova; Shakila Thangaratinam; Kim Boers; Corine M. Koopmans; Kedra Wallace; Andrew Shennan; Josje Langenveld; Henk Groen; Paul P. van den Berg; Ben W.J. Mol; Maureen Franssen

Like many other research subjects in obstetrics, research on immediate delivery versus expectant monitoring for women with hypertensive disorders of pregnancy faces certain challenges when it comes to interpretation and generalisation of the results; relatively rare outcomes are studied, in a clinically heterogeneous population, while the clinical practice in some countries has dictated that studies in term pregnancy were completed before earlier gestational ages could be studied. This has resulted in multiple smaller studies, some studying surrogate outcome measures, with different in- and exclusion criteria, and without enough power for reliable subgroup analyses. All this complicates the generation of definitive answers and implementation of the results into clinical practice. Performing multiple studies and subsequently pooling their results in a meta-analysis can be a way to overcome the difficulties of studying relatively rare outcomes and subgroups with enough power, as well as a solution to reach a final answer on questions involving an uncertain and possibly harmful intervention. However, in the case of the current studies on delivery versus expectant monitoring in women with hypertensive disorders of pregnancy, differences regarding eligibility criteria, outcome measures and subgroup definitions make it difficult to pool their results in an aggregate meta-analysis. Individual patient data meta-analysis (IPDMA) has the potential to overcome these challenges, because it allows for flexibility regarding the choice of endpoints and standardisation of inclusion and exclusion criteria across studies. In addition, it has more statistical power for informative subgroup analyses. We therefore propose an IPDMA on immediate delivery versus expectant monitoring for hypertensive disorders of pregnancy, and advocate the use of IPDMA for research questions in obstetrics that face similar challenges.


European Journal of Obstetrics & Gynecology and Reproductive Biology | 2016

Can we identify subfertile couples that benefit from immediate in vitro fertilisation over intrauterine insemination

R.I. Tjon-Kon-Fat; Parvin Tajik; Inge M. Custers; P.M.M. Bossuyt; Fulco van der Veen; Madelon van Wely; B.W.J. Mol; Mohammad Hadi Zafarmand

OBJECTIVE Available treatment options in couples with unexplained or mild male subfertility are intrauterine insemination with controlled ovarian hyperstimulation (IUI-COH) and in vitro fertilisation (IVF). IUI-COH is a less invasive treatment that is often used before proceeding with IVF. Yet as the IVF success rates might be higher and time to pregnancy shorter, expedited access to IVF might be the preferred option. To identify couples that could benefit from immediate IVF over IUI-COH, we assessed whether female age, duration of subfertility or prewash total motile count (TMC) can help to identify couples that would benefit from IVF over IUI-COH. STUDY DESIGN We performed a secondary data-analysis of a multicentre open-label randomised controlled trial in three university and six teaching hospitals in the Netherlands. 116 couples with unexplained or mild male subfertility were randomised to one cycle of IVF with elective single embryo transfer with subsequent frozen-thawed embryo transfers or 3 cycles of IUI-COH. The primary outcome was an ongoing pregnancy within 4 months after randomisation. Our aim was to explore a possible differential effect of specific markers on the effectiveness of treatment. We chose to therefore assess female age, duration of subfertility and TMC as these have previously been identified as predictors. For each prognostic factor we developed a logistic regression model to predict ongoing pregnancy with that prognostic factor, treatment and a factor-by-treatment interaction term. RESULTS Female age and duration of subfertility were not associated with better ongoing pregnancy chances after IVF compared to IUI-COH (p-value for interaction=0.65 and 0.26, respectively). Only when TMC was lower than 110 (×10(6)spermatozoa/mL), the probability of ongoing pregnancy was higher in women allocated to IVF (p-value for interaction=0.06). CONCLUSION In couples with unexplained or mild male subfertility, a low TMC might lead to higher pregnancy rates after IVF than after IUI-COH. This finding needs to be validated in a larger trial before it can be applied in clinical practice.

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Corine M. Koopmans

University Medical Center Groningen

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Maureen Franssen

University Medical Center Groningen

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Henk Groen

Drug Abuse Resistance Education

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Kim Boers

Leiden University Medical Center

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