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Dive into the research topics where J. Alfred Witjes is active.

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Featured researches published by J. Alfred Witjes.


Nature Genetics | 2007

Genome-wide association study identifies a second prostate cancer susceptibility variant at 8q24

Julius Gudmundsson; Patrick Sulem; Andrei Manolescu; Laufey T Amundadottir; Daniel F. Gudbjartsson; Agnar Helgason; Thorunn Rafnar; Jon Thor Bergthorsson; Bjarni A. Agnarsson; Adam Baker; Asgeir Sigurdsson; Kristrun R. Benediktsdottir; Margret Jakobsdottir; Jianfeng Xu; Thorarinn Blondal; Jelena Kostic; Jielin Sun; Shyamali Ghosh; Simon N. Stacey; Magali Mouy; Jona Saemundsdottir; Valgerdur M. Backman; Kristleifur Kristjansson; Alejandro Tres; Alan W. Partin; Marjo T Albers-Akkers; Javier Godino-Ivan Marcos; Patrick C. Walsh; Dorine W. Swinkels; Sebastian Navarrete

Prostate cancer is the most prevalent noncutaneous cancer in males in developed regions, with African American men having among the highest worldwide incidence and mortality rates. Here we report a second genetic variant in the 8q24 region that, in conjunction with another variant we recently discovered, accounts for about 11%–13% of prostate cancer cases in individuals of European descent and 31% of cases in African Americans. We made the current discovery through a genome-wide association scan of 1,453 affected Icelandic individuals and 3,064 controls using the Illumina HumanHap300 BeadChip followed by four replication studies. A key step in the discovery was the construction of a 14-SNP haplotype that efficiently tags a relatively uncommon (2%–4%) susceptibility variant in individuals of European descent that happens to be very common (∼42%) in African Americans. The newly identified variant shows a stronger association with affected individuals who have an earlier age at diagnosis.


European Urology | 2011

Treatment of Muscle-Invasive and Metastatic Bladder Cancer: Update of the EAU Guidelines.

Arnulf Stenzl; Nigel C. Cowan; Maria De Santis; Markus A. Kuczyk; Axel S. Merseburger; M.J. Ribal; Amir Sherif; J. Alfred Witjes

CONTEXT New data regarding treatment of muscle-invasive and metastatic bladder cancer (MiM-BC) has emerged and led to an update of the European Association of Urology (EAU) guidelines for MiM-BC. OBJECTIVE To review the new EAU guidelines for MiM-BC with a specific focus on treatment. EVIDENCE ACQUISITION New literature published since the last update of the EAU guidelines in 2008 was obtained from Medline, the Cochrane Database of Systematic Reviews, and reference lists in publications and review articles and comprehensively screened by a group of urologists, oncologists, and a radiologist appointed by the EAU Guidelines Office. Previous recommendations based on the older literature on this subject were also taken into account. Levels of evidence (LEs) and grades of recommendations (GRs) were added based on a system modified from the Oxford Centre for Evidence-based Medicine Levels of Evidence. EVIDENCE SYNTHESIS Current data demonstrate that neoadjuvant chemotherapy in conjunction with radical cystectomy (RC) is recommended in certain constellations of MiM-BC. RC remains the basic treatment of choice in localised invasive disease for both sexes. An attempt has been made to define the extent of surgery under standard conditions in both sexes. An orthotopic bladder substitute should be offered to both male and female patients lacking any contraindications, such as no tumour at the level of urethral dissection. In contrast to neoadjuvant chemotherapy, current advice recommends the use of adjuvant chemotherapy only within clinical trials. Multimodality bladder-preserving treatment in localised disease is currently regarded only as an alternative in selected, well-informed, and compliant patients for whom cystectomy is not considered for medical or personal reasons. In metastatic disease, the first-line treatment for patients fit enough to sustain cisplatin remains cisplatin-containing combination chemotherapy. With the advent of vinflunine, second-line chemotherapy has become available. CONCLUSIONS In the treatment of localised invasive bladder cancer (BCa), the standard treatment remains radical surgical removal of the bladder within standard limits, including as-yet-unspecified regional lymph nodes. However, the addition of neoadjuvant chemotherapy must be considered for certain specific patient groups. A new drug for second-line chemotherapy (vinflunine) in metastatic disease has been approved and is recommended.


Nature Genetics | 2008

Many sequence variants affecting diversity of adult human height

Daniel F. Gudbjartsson; G. Bragi Walters; Gudmar Thorleifsson; Hreinn Stefansson; Bjarni V. Halldórsson; Pasha Zusmanovich; Patrick Sulem; Steinunn Thorlacius; Arnaldur Gylfason; Stacy Steinberg; Anna Helgadottir; Andres Ingason; Valgerdur Steinthorsdottir; Elinborg J Olafsdottir; Gudridur Olafsdottir; Thorvaldur Jonsson; Knut Borch-Johnsen; Torben Hansen; Gitte Andersen; Torben Jørgensen; Oluf Pedersen; Katja K. Aben; J. Alfred Witjes; Dorine W. Swinkels; Martin den Heijer; Barbara Franke; A.L.M. Verbeek; Diane M. Becker; Lisa R. Yanek; Lewis C. Becker

Adult human height is one of the classical complex human traits. We searched for sequence variants that affect height by scanning the genomes of 25,174 Icelanders, 2,876 Dutch, 1,770 European Americans and 1,148 African Americans. We then combined these results with previously published results from the Diabetes Genetics Initiative on 3,024 Scandinavians and tested a selected subset of SNPs in 5,517 Danes. We identified 27 regions of the genome with one or more sequence variants showing significant association with height. The estimated effects per allele of these variants ranged between 0.3 and 0.6 cm and, taken together, they explain around 3.7% of the population variation in height. The genes neighboring the identified loci cluster in biological processes related to skeletal development and mitosis. Association to three previously reported loci are replicated in our analyses, and the strongest association was with SNPs in the ZBTB38 gene.


European Urology | 2014

EAU Guidelines on Muscle-invasive and Metastatic Bladder Cancer: Summary of the 2013 Guidelines

J. Alfred Witjes; Eva Comperat; Nigel C. Cowan; Maria De Santis; Georgios Gakis; Thierry Lebret; M.J. Ribal; Antoine G. van der Heijden; Amir Sherif

CONTEXT The European Association of Urology (EAU) guidelines panel on Muscle-invasive and Metastatic bladder cancer (BCa) updates its guidelines yearly. This updated summary provides a synthesis of the 2013 guidelines document, with emphasis on the latest developments. OBJECTIVE To provide graded recommendations on the diagnosis and treatment of patients with muscle-invasive BCa (MIBC), linked to a level of evidence. EVIDENCE ACQUISITION For each section of the guidelines, comprehensive literature searches covering the past 10 yr in several databases were conducted, scanned, reviewed, and discussed both within the panel and with external experts. The final results are reflected in the recommendations provided. EVIDENCE SYNTHESIS Smoking and work-related carcinogens remain the most important risk factors for BCa. Computed tomography (CT) and magnetic resonance imaging can be used for staging, although CT is preferred for pulmonary evaluation. Open radical cystectomy with an extended lymph node dissection (LND) remains the treatment of choice for treatment failures in non-MIBC and T2-T4aN0M0 BCa. For well-informed, well-selected, and compliant patients, however, multimodality treatment could be offered as an alternative, especially if cystectomy is not an option. Comorbidity, not age, should be used when deciding on radical cystectomy. Patients should be encouraged to actively participate in the decision-making process, and a continent urinary diversion should be offered to all patients unless there are specific contraindications. For fit patients, cisplatinum-based neoadjuvant chemotherapy should always be discussed, since it improves overall survival. For patients with metastatic disease, cisplatin-containing combination chemotherapy is recommended. For unfit patients, carboplatin combination chemotherapy or single agents can be used. CONCLUSIONS This 2013 EAU Muscle-invasive and Metastatic BCa guidelines updated summary aims to increase the quality of care and outcome for patients with muscle-invasive or metastatic BCa. PATIENT SUMMARY In this paper we update the EAU guidelines on Muscle-invasive and Metastatic bladder cancer. We recommend that chemotherapy be administered before radical treatment and that bladder removal be the standard of care for disease confined to the bladder.


European Urology | 2003

DD3PCA3-based molecular urine analysis for the diagnosis of prostate cancer

Daphne Hessels; Jacqueline M.T. Klein Gunnewiek; Inge M. van Oort; H. F. M. Karthaus; Geert J.L.H. van Leenders; Bianca van Balken; Lambertus A. Kiemeney; J. Alfred Witjes; Jack A. Schalken

BACKGROUND: DD3(PCA3) is the most prostate cancer-specific gene described to date. To assess the clinical utility of DD3(PCA3) a time-resolved fluorescence-based, quantitative RT-PCR analysis for DD3(PCA3) was developed. METHODS: The diagnostic potential of DD3(PCA3) was determined by quantitative measurement of DD3(PCA3) transcripts in non-malignant and malignant prostate specimens. Moreover, DD3(PCA3) transcripts were determined quantitatively in urine sediments obtained after prostatic massage. A cohort of 108 men, admitted for prostate biopsies based on a PSA of >3ng/ml, was studied. RESULTS: Prostate tumors showed a 66-fold up-regulation of DD3(PCA3) (median 158.4.10(5) copies/microg tissue RNA) when compared to benign prostate tissue (median 2.4.10(5) copies/microg tissue RNA). This up-regulation was found in more than 95% of prostate cancer specimens studied. These data revealed that specimens with less than 10% of cancer cells could be accurately discriminated from non-cancer tissues. Hence, detection of a small fraction of prostate cancer cells in a background of normal cells seemed feasible. Therefore, this DD3(PCA3)-based RT-PCR assay was used for the identification of prostate cancer in urine sediments obtained after prostatic massage. From 108 men with a serum PSA value >3ng/ml, 24 men were shown to have prostate cancer upon biopsy. Of these 24 men, 16 were shown to be positive for DD3(PCA3), indicating a sensitivity of the assay of 67%. Furthermore, a negative predictive value of 90% was calculated. CONCLUSION: The quantitative RT-PCR assay for DD3(PCA3) described, bears great promise as a tool for molecular urine analysis. It has great potential in reducing the number of unnecessary biopsies. A multi-center study using this DD3(PCA3) assay can provide the basis for the utility of molecular diagnostics in clinical urological practice.


European Urology | 2009

An Individual Patient Data Meta-Analysis of the Long-Term Outcome of Randomised Studies Comparing Intravesical Mitomycin C versus Bacillus Calmette-Guérin for Non–Muscle-Invasive Bladder Cancer

Per-Uno Malmström; Richard Sylvester; David Crawford; Martin G. Friedrich; Susanne Krege; Erkki Rintala; E. Solsona; Savino M. Di Stasi; J. Alfred Witjes

BACKGROUND Patients with non-muscle-invasive bladder cancer with an intermediate or high risk need adjuvant intravesical therapy after surgery. Based largely on meta-analyses of previously published results, guidelines recommend using either bacillus Calmette-Guérin (BCG) or mitomycin C (MMC) in these patients. Individual patient data (IPD) meta-analyses, however, are the gold standard. OBJECTIVE To compare the efficacy of BCG and MMC based on an IPD meta-analysis of randomised trials. DESIGN, SETTING, AND PARTICIPANTS Trials were searched through Medline and review articles. The relevant trial investigators were contacted to provide IPD. MEASUREMENTS The drugs were compared with respect to time to recurrence, progression, and overall and cancer-specific death. RESULTS AND LIMITATIONS Nine trials that included 2820 patients were identified, and IPD were obtained from all of them. Patient characteristics were 71% primary, 54% Ta, 43% T1, 25% G1, 58% G2, and 16% G3, and 7% had prior intravesical chemotherapy. Based on a median follow-up of 4.4 yr, 43% recurred. Overall, there was no difference in the time to first recurrence (p=0.09) between BCG and MMC. In the trials with BCG maintenance, a 32% reduction in risk of recurrence on BCG compared to MMC was found (p<0.0001), while there was a 28% risk increase (p=0.006) for BCG in the trials without maintenance. BCG with maintenance was more effective than MMC in both patients previously treated and those not previously treated with chemotherapy. In the subset of 1880 patients for whom data on progression, survival, and cause of death were available, 12% progressed and 24% died, and, of those, 30% of the deaths were due to bladder cancer. No statistically significant differences were found for these long-term end points. CONCLUSIONS For prophylaxis of recurrence, maintenance BCG is required to demonstrate superiority to MMC. Prior intravesical chemotherapy was not a confounder. There were no statistically significant differences regarding progression, overall survival, and cancer-specific survival between the two treatments.


European Urology | 2009

Recurrence and Progression of Disease in Non–Muscle-Invasive Bladder Cancer: From Epidemiology to Treatment Strategy

Bas W. G. van Rhijn; Maximilian Burger; Yair Lotan; Eduardo Solsona; Christian G. Stief; Richard Sylvester; J. Alfred Witjes; Alexandre Zlotta

CONTEXT This review focuses on the prediction of recurrence and progression in non-muscle invasive bladder cancer (NMIBC) and the treatments advocated for this disease. OBJECTIVE To review the current status of epidemiology, recurrence, and progression of NMIBC and the state-of-the art treatment for this disease. EVIDENCE ACQUISITION A literature search in English was performed using PubMed and the guidelines of the European Association of Urology and the American Urological Association. Relevant papers on epidemiology, recurrence, progression, and management of NMIBC were selected. Special attention was given to fluorescent cystoscopy, the new World Health Organisation 2004 classification system for grade, and the role of substaging of T1 NMIBC. EVIDENCE SYNTHESIS In NMIBC, approximately 70% of patients present as pTa, 20% as pT1, and 10% with carcinoma in situ (CIS) lesions. Bladder cancer (BCa) is the fifth most frequent type of cancer in western society and the most expensive cancer per patient. Recurrence (in < or = 80% of patients) is the main problem for pTa NMIBC patients, whereas progression (in < or = 45% of patients) is the main threat in pT1 and CIS NMIBC. In a recent European Organisation for Research and Treatment of Cancer analysis, multiplicity, tumour size, and prior recurrence rate are the most important variables for recurrence. Tumour grade, stage, and CIS are the most important variables for progression. Treatment ranges from transurethral resection (TUR) followed by a single chemotherapy instillation in low-risk NMIBC to, sometimes, re-TUR and adjuvant intravesical therapy in intermediate- and high-risk patients to early cystectomy for treatment-refractory high-risk NMIBC. CONCLUSIONS NMIBC is a heterogeneous disease with varying therapies, follow-up strategies, and oncologic outcomes for an individual patient.


Nature Genetics | 2008

Common sequence variants on 2p15 and Xp11.22 confer susceptibility to prostate cancer

Julius Gudmundsson; Patrick Sulem; Thorunn Rafnar; Jon Thor Bergthorsson; Andrei Manolescu; Daniel F. Gudbjartsson; Bjarni A. Agnarsson; Asgeir Sigurdsson; Kristrun R. Benediktsdottir; Thorarinn Blondal; Margret Jakobsdottir; Simon N. Stacey; Jelena Kostic; Kari T. Kristinsson; Birgitta Birgisdottir; Shyamali Ghosh; Droplaug N. Magnusdottir; Steinunn Thorlacius; Gudmar Thorleifsson; S. Lilly Zheng; Jielin Sun; Bao Li Chang; J. Bradford Elmore; Joan P. Breyer; Kate M. McReynolds; Kevin M. Bradley; Brian L. Yaspan; Fredrik Wiklund; Pär Stattin; Sara Lindström

We conducted a genome-wide SNP association study on prostate cancer on over 23,000 Icelanders, followed by a replication study including over 15,500 individuals from Europe and the United States. Two newly identified variants were shown to be associated with prostate cancer: rs5945572 on Xp11.22 and rs721048 on 2p15 (odds ratios (OR) = 1.23 and 1.15; P = 3.9 × 10−13 and 7.7 × 10−9, respectively). The 2p15 variant shows a significantly stronger association with more aggressive, rather than less aggressive, forms of the disease.


Nature Genetics | 2008

Sequence variant on 8q24 confers susceptibility to urinary bladder cancer

Lambertus A. Kiemeney; Steinunn Thorlacius; Patrick Sulem; Frank Geller; Katja K. Aben; Simon N. Stacey; Julius Gudmundsson; Margret Jakobsdottir; Jon Thor Bergthorsson; Asgeir Sigurdsson; Thorarinn Blondal; J. Alfred Witjes; Sita H. Vermeulen; Christina A. Hulsbergen-van de Kaa; Dorine W. Swinkels; Martine Ploeg; Erik B. Cornel; H. Vergunst; Thorgeir E. Thorgeirsson; Daniel F. Gudbjartsson; Sigurjon A. Gudjonsson; Gudmar Thorleifsson; Kari T. Kristinsson; Magali Mouy; Steinunn Snorradottir; Donatella Placidi; Marcello Campagna; Cecilia Arici; Kvetoslava Koppova; Eugene Gurzau

We conducted a genome-wide SNP association study on 1,803 urinary bladder cancer (UBC) cases and 34,336 controls from Iceland and The Netherlands and follow up studies in seven additional case-control groups (2,165 cases and 3,800 controls). The strongest association was observed with allele T of rs9642880 on chromosome 8q24, 30 kb upstream of MYC (allele-specific odds ratio (OR) = 1.22; P = 9.34 × 10−12). Approximately 20% of individuals of European ancestry are homozygous for rs9642880[T], and their estimated risk of developing UBC is 1.49 times that of noncarriers. No association was observed between UBC and the four 8q24 variants previously associated with prostate, colorectal and breast cancers, nor did rs9642880 associate with any of these three cancers. A weaker signal, but nonetheless of genome-wide significance, was captured by rs710521[A] located near TP63 on chromosome 3q28 (allele-specific OR = 1.19; P = 1. 15 × 10−7).


The Journal of Urology | 2010

Magnetic Resonance Imaging Guided Prostate Biopsy in Men With Repeat Negative Biopsies and Increased Prostate Specific Antigen

Thomas Hambrock; D.M. Somford; C.M.A. Hoeks; Stefan A.W. Bouwense; Henkjan J. Huisman; Derya Yakar; Inge M. van Oort; J. Alfred Witjes; Jurgen J. Fütterer; Jelle O. Barentsz

PURPOSE Undetected cancer in repeat transrectal ultrasound guided prostate biopsies in patients with increased prostate specific antigen greater than 4 ng/ml is a considerable concern. We investigated the tumor detection rate of tumor suspicious regions on multimodal 3 Tesla magnetic resonance imaging and subsequent magnetic resonance imaging guided biopsy in 68 men with repeat negative transrectal ultrasound guided prostate biopsies. We compared results to those in a matched transrectal ultrasound guided prostate biopsy population. Also, we determined the clinical significance of detected tumors. MATERIALS AND METHODS A total of 71 consecutive patients with prostate specific antigen greater than 4 ng/ml and 2 or greater negative transrectal ultrasound guided prostate biopsy sessions underwent multimodal 3 Tesla magnetic resonance imaging. In 68 patients this was followed by magnetic resonance imaging guided biopsy directed toward tumor suspicious regions. A matched multisession transrectal ultrasound guided prostate biopsy population from our institutional database was used for comparison. The clinical significance of detected tumors was established using accepted criteria, including prostate specific antigen, Gleason grade, stage and tumor volume. RESULTS The tumor detection rate of multimodal 3 Tesla magnetic resonance imaging guided biopsy was 59% (40 of 68 cases) using a median of 4 cores. The tumor detection rate was significantly higher than that of transrectal ultrasound guided prostate biopsy in all patient subgroups (p <0.01) except in those with prostate specific antigen greater than 20 ng/ml, prostate volume greater than 65 cc and prostate specific antigen density greater than 0.5 ng/ml/cc, in which similar rates were achieved. Of the 40 patients with identified tumors 37 (93%) were considered highly likely to harbor clinically significant disease. CONCLUSIONS Multimodal magnetic resonance imaging is an effective technique to localize prostate cancer. Magnetic resonance imaging guided biopsy of tumor suspicious regions is an accurate method to detect clinically significant prostate cancer in men with repeat negative biopsies and increased prostate specific antigen.

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Jelle O. Barentsz

Radboud University Nijmegen

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Inge M. van Oort

Radboud University Nijmegen

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Daphne Hessels

Radboud University Nijmegen Medical Centre

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Katja K. Aben

Radboud University Nijmegen

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Richard Sylvester

European Organisation for Research and Treatment of Cancer

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