Peter-Paul Willemse

Dr. Peter-Paul Willemse

University Medical Center Utrecht, Utrecht, The Netherlands
orcid

Research Focus & Metrics

Academic Career Length

6Years (2021-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 April 2022 in European Urology
Verified
Journal Article
Open access
PWPeter-Paul Willemse
Peter-Paul Willemse
NDNiall F. Davis
Niall F. Davis
NGNikolaos Grivas
Nikolaos Grivas
FZFabio Zattoni
Fabio Zattoni
MLMichael Lardas
Michael Lardas
TLThomas B.L. Lam
Thomas B.L. Lam
There is uncertainty regarding the most appropriate criteria for recruitment, monitoring, and reclassification in active surveillance (AS) protocols for localised prostate cancer (PCa). To perform a qualitative systematic review (SR) to issue recommendations regarding inclusion of intermediate-risk disease, biopsy characteristics at inclusion and monitoring, and repeat biopsy strategy. A protocol-driven, Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA)-adhering SR incorporating AS protocols published from January 1990 to October 2020 was performed. The main outcomes were criteria for inclusion of intermediate-risk disease, monitoring, reclassification, and repeat biopsy strategies (per protocol and/or triggered). Clinical effectiveness data were not assessed. Of the 17 011 articles identified, 333 studies incorporating 375 AS protocols, recruiting 264 852 patients, were included. Only a minority of protocols included the use of magnetic resonance imaging (MRI) for recruitment (n = 17), follow-up (n = 47), and reclassification (n = 26). More than 50% of protocols included patients with intermediate or high-risk disease, whilst 44.1% of protocols excluded low-risk patients with more than three positive cores, and 39% of protocols excluded patients with core involvement (CI) >50% per core. Of the protocols, ≥80% mandated a confirmatory transrectal ultrasound biopsy; 72% (n = 189) of protocols mandated per-protocol repeat biopsies, with 20% performing this annually and 25% every 2 yr. Only 27 protocols (10.3%) mandated triggered biopsies, with 74% of these protocols defining progression or changes on MRI as triggers for repeat biopsy. For AS protocols in which the use of MRI is not mandatory or absent, we recommend the following: (1) AS can be considered in patients with low-volume International Society of Urological Pathology (ISUP) grade 2 (three or fewer positive cores and cancer involvement ≤50% CI per core) or another single element of intermediate-risk disease, and patients with ISUP 3 should be excluded; (2) per-protocol confirmatory prostate biopsies should be performed within 2 yr, and per-protocol surveillance repeat biopsies should be performed at least once every 3 yr for the first 10 yr; and (3) for patients with low-volume, low-risk disease at recruitment, if repeat systematic biopsies reveal more than three positive cores or maximum CI >50% per core, they should be monitored closely for evidence of adverse features (eg, upgrading); patients with ISUP 2 disease with increased core positivity and/or CI to similar thresholds should be reclassified. We examined the literature to issue new recommendations on active surveillance (AS) for managing localised prostate cancer. The recommendations include setting criteria for including men with more aggressive disease (intermediate-risk disease), setting thresholds for close monitoring of men with low-risk but more extensive disease, and determining when to perform repeat biopsies (within 2 yr and 3 yearly thereafter).

27 October 2021 in Cancers
Verified
Journal Article
Open access
PDF file
RFRachel Flach
Rachel Flach
PWPeter-Paul Willemse
Peter-Paul Willemse
BSBritt B. M. Suelmann
Britt B. M. Suelmann
IDIvette A. G. Deckers
Ivette A. G. Deckers
TJTrudy N. Jonges
Trudy N. Jonges
RMRichard P. Meijer
Richard P. Meijer
Purpose: Our aim was to analyze grading variation between pathology laboratories and between pathologists within individual laboratories using nationwide real-life data. Methods: We retrieved synoptic (n = 13,397) and narrative (n = 29,377) needle biopsy reports from the Dutch Pathology Registry and prostate-specific antigen values from The Netherlands Cancer Registration for prostate cancer patients diagnosed between January 2017 and December 2019. We determined laboratory-specific proportions per histologic grade and unadjusted odds ratios (ORs) for International Society of Urological Pathologists Grades 1 vs. 2–5 for 40 laboratories due to treatment implications for higher grades. Pathologist-specific proportions were determined for 21 laboratories that consented to this part of analysis. The synoptic reports of 21 laboratories were used for analysis of case-mix correction for PSA, age, year of diagnosis, number of biopsies and positive cores. Results: A total of 38,321 reports of 35,258 patients were included. Grade 1 ranged between 19.7% and 44.3% per laboratory (national mean = 34.1%). Out of 40 laboratories, 22 (55%) reported a significantly deviant OR, ranging from 0.48 (95% confidence interval (CI) 0.39–0.59) to 1.54 (CI 1.22–1.93). Case-mix correction was performed for 10,294 reports, altering the status of 3/21 (14%) laboratories, but increasing the observed variation (20.8% vs. 17.7%). Within 15/21 (71%) of laboratories, significant inter-pathologist variation existed. Conclusion: Substantial variation in prostate cancer grading was observed between and within Dutch pathology laboratories. Case-mix correction did not explain the variation. Better standardization of prostate cancer grading is warranted to optimize and harmonize treatment.

8 May 2023 in NMR in Biomedicine
Verified
Journal Article
Open access
DRDaan J. Reesink
Daan J. Reesink
CCCatalina S. Arteaga de Castro
Catalina S. Arteaga de Castro
TVTijl Van der Velden
Tijl Van der Velden
JVJeanette Van Vooren
Jeanette Van Vooren
POPetri Oost
Petri Oost
DKDennis W. J. Klomp
Dennis W. J. Klomp
Chemical exchange saturation transfer (CEST) has been explored for differentiation between tumour and benign tissue in prostate cancer (PCa) patients. With ultrahigh field strengths such as 7‐T, the increase of spectral resolution and sensitivity could allow for selective detection of amide proton transfer (APT) at 3.5 ppm and a group of compounds that resonate at 2 ppm (i.e., [poly]amines and/or creatine). The potential of 7‐T multipool CEST analysis of the prostate and the detection of PCa was studied in patients with proven localised PCa who were scheduled to undergo robot‐assisted radical prostatectomy (RARP). Twelve patients were prospectively included (mean age 68.0 years, mean serum prostate‐specific antigen 7.8ng/mL). A total of 24 lesions larger than 2 mm were analysed. Used were 7‐T T2‐weighted (T2W) imaging and 48 spectral CEST points. Patients received 1.5‐T/3‐T prostate magnetic resonance imaging and galium‐68‐prostate‐specific membrane antigen‐positron emission tomography/computerised tomography to determine the location of the single‐slice CEST. Based on the histopathological results after RARP, three regions of interest were drawn on the T2W images from a known malignant zone and benign zone in the central and peripheral zones. These areas were transposed to the CEST data, from which the APT and 2‐ppm CEST were calculated. The statistical significance of the CEST between the central zone, the peripheral zone, and tumour was calculated using a Kruskal–Wallis test. The z‐spectra showed that APT and even a distinct pool that resonated at 2 ppm were detectable. This study showed a difference trend in the APT levels, but no difference in the 2‐ppm levels when tested between the central zone, the peripheral zone, and tumour (H(2) = 4.8, p = 0.093 and H(2) = 0.86, p = 0.651, respectively). Thus, to conclude, we could most likely detect APT and amines and/or creatine levels noninvasively in prostate using the CEST effect. At group level, CEST showed a higher level of APT in the peripheral versus the central zone; however, no differences of APT and 2‐ppm levels were observed in tumours.

3 November 2022 in Journal of Clinical Pathology
Verified
Journal Article
Closed access
PDF file
RFRachel Flach
Rachel Flach
LELars Egevad
Lars Egevad
MEMartin Eklund
Martin Eklund
TKTheodorus H van der Kwast
Theodorus H van der Kwast
BDBrett Delahunt
Brett Delahunt
PDPaul J van Diest
Paul J van Diest
Aims Prostate cancer (PCa) grading is an important prognostic parameter, but is subject to considerable observer variation. Previous studies have shown that interobserver variability decreases after participants were trained using an e-learning module. However, since the publication of these studies, grading of PCa has been enhanced by adopting the International Society of Urological Pathology (ISUP) 2014 grading classification. This study investigates the effect of training on interobserver variability of PCa grading, using the ISUP Education web e-learning on Gleason grading. Methods The ISUP Education Prostate Test B Module was distributed among Dutch pathologists. The module uses images graded by the ISUP consensus panel consisting of 24 expert uropathologists. Participants graded the same 10 images before and after e-learning. We included those who completed the tests before and after training. We evaluated variation in PCa grading in a fully crossed study design, using linearly weighted kappa values for each pathologist, comparing them to other pathologists and to the ISUP consensus panel. We analysed the improvement in median weighted kappas before and after training, using Wilcoxon’s signed rank-test. Results We included 42 pathologists. Inter-rater reliability between pathologists improved from 0.70 before training to 0.74 after training (p=0.01). When compared with the ISUP consensus panel, five pathologists improved significantly, whereas the kappa of one pathologist was significantly lower after training. All pathologists who improved significantly, graded with less than substantial agreement before training. Conclusions ISUP Prostate Test B e-learning reduces variability in PCa grading. E-learning is a cost-effective method for standardisation of pathology.

25 March 2024 in European Urology Open Science
Verified
Journal Article
Open access
PRPawel Rajwa
Pawel Rajwa
ABAngelika Borkowetz
Angelika Borkowetz
TAThomas Abbott
Thomas Abbott
AAAndrea Alberti
Andrea Alberti
ABAnders Bjartell
Anders Bjartell
PWPeter-Paul Willemse
Peter-Paul Willemse
Despite their efficacy, novel combination systemic therapies for metastatic hormone-sensitive prostate cancer (mHSPC) are associated with side effects. Our study reports drug-related adverse events in a large cohort of “real-life” patients treated with combination therapies for mHSPC.

18 August 2022 in BJUI Compass
Verified
Journal Article
Open access
JVJosephina P. M. Vrouwe
Josephina P. M. Vrouwe
PHPauline M. L. Hennus
Pauline M. L. Hennus
NHNeveen A. T. Hamdy
Neveen A. T. Hamdy
SOSusanne Osanto
Susanne Osanto
PWPeter-Paul Willemse
Peter-Paul Willemse
Context: Testicular germ cell tumour (TGCT) survivors are potentially at risk of developing osteoporosis, because of increased risk for disturbed bone remodelling associated with hypogonadism and anti‐cancer treatment. A number of studies show bone loss and increased fracture risk in TGCT survivors, but data are scarce. There are no clinical guidelines or recommendations issued to address skeletal health in this group of patients potentially at high risk for osteoporosis.Objective: To conduct a systematic review of available literature addressing bone health in TGCT patients. Subgroup analysis was performed to identify risk factors for bone loss and increased fracture risk.Evidence Acquisition: Relevant databases, including MEDLINE, Embase and the Cochrane Library, including all English written comparative studies addressing bone health in TGCT patients, were searched up to December 2021 and a narrative synthesis was undertaken. Risk of bias (RoB) was assessed using Cochrane ROBINS‐I tool.Evidence Synthesis: Ten studies (eight cross‐sectional and two longitudinal), recruiting a total of 1997 unique TGCT patients, were identified and included in the analysis. Bone health was reported in various ways in different studies, and subgroups were defined heterogeneously, resulting in a widely varying prevalence of osteoporosis of up to 73.2% of patients. Six studies reported low BMD associated with higher luteinizing hormone levels and one study showed a correlation between follow up duration and bone loss.Conclusions: TGCT survivors are at risk of developing osteoporosis and sustaining fragility fractures. Chemotherapy, pituitary‐gonadal axis dysfunction and ageing are key risk factors, although available data are scarce. With increasing survival of TGCT patients, a clear unmet need has been identified to systematically evaluate and monitor skeletal health in larger numbers of survivors in order to develop best clinical practice guidelines to manage the insidious but potentially preventable and treatable skeletal complications of TGCT.