Koen Peeters

Dr. Koen Peeters

orcid

Research Focus & Metrics

Academic Career Length

23Years (2004-Present)

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

Representative Publications

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1 November 2007 in Annals of Surgery
Verified
Journal Article
Closed access
KPKoen Peeters
Koen Peeters
CMCorrie A M Marijnen
Corrie A M Marijnen
INIris D. Nagtegaal
Iris D. Nagtegaal
EMElma Meershoek
Elma Meershoek
HPHein Putter
Hein Putter
DGDutch Colorectal Cancer Group
Dutch Colorectal Cancer Group
To investigate the efficacy of preoperative short-term radiotherapy in patients with mobile rectal cancer undergoing total mesorectal excision (TME) surgery. Local recurrence is a major problem in rectal cancer treatment. Preoperative short-term radiotherapy has shown to improve local control and survival in combination with conventional surgery. The TME trial investigated the value of this regimen in combination with total mesorectal excision. Long-term results are reported after a median follow-up of 6 years. One thousand eight hundred and sixty-one patients with resectable rectal cancer were randomized between TME preceded by 5 × 5 Gy or TME alone. No chemotherapy was allowed. There was no age limit. Surgery, radiotherapy, and pathologic examination were standardized. Primary endpoint was local control. Median follow-up of surviving patients was 6.1 year. Five-year local recurrence risk of patients undergoing a macroscopically complete local resection was 5.6% in case of preoperative radiotherapy compared with 10.9% in patients undergoing TME alone (P < 0.001). Overall survival at 5 years was 64.2% and 63.5%, respectively (P = 0.902). Subgroup analyses showed significant effect of radiotherapy in reducing local recurrence risk for patients with nodal involvement, for patients with lesions between 5 and 10 cm from the anal verge, and for patients with uninvolved circumferential resection margins. With increasing follow-up, there is a persisting overall effect of preoperative short-term radiotherapy on local control in patients with clinically resectable rectal cancer. However, there is no effect on overall survival. Since survival is mainly determined by distant metastases, efforts should be directed towards preventing systemic disease.

1 March 2017 in Cancer Treatment Reviews
Verified
Journal Article
Closed access
NVN.C.A. Vermeer
N.C.A. Vermeer
HSH.S. Snijders
H.S. Snijders
FHF.A. Holman
F.A. Holman
GLG.J. Liefers
G.J. Liefers
EBE. Bastiaannet
E. Bastiaannet
KPKoen Peeters
Koen Peeters

3 February 2005 in Cancer
Verified
Journal Article
Open access
PDF file
KPKoen Peeters
Koen Peeters
MKMichael Kattan
Michael Kattan
HHHenk H. Hartgrink
Henk H. Hartgrink
EMElma Meershoek
Elma Meershoek
MKMartin S. Karpeh
Martin S. Karpeh
CVCornelis J.H. van de Velde
Cornelis J.H. van de Velde
BACKGROUND A statistical model for predicting disease‐specific survival in patients with gastric carcinoma, based on a single U.S. institution experience, was tested for validity in a sample of patients treated at different institutions. METHODS The authors analysed 459 patients from the Dutch Gastric Cancer trial that compared limited (D1) with extended (D2) lymph node dissection. The discrimination ability of the nomogram with respect to 5 and 9‐year disease‐specific survival probabilities was superior to that of the American Joint Committee on Cancer (AJCC) staging system. RESULTS There was considerable heterogeneity of risk within many of the AJCC stages. Calibration plots suggested that predicted probabilities from the nomogram corresponded closely to actual disease‐specific survival. The gastric carcinoma nomogram performed well when applied to patients treated in a large number of institutions. CONCLUSIONS The nomogram provided predictions that discriminated better than the AJCC staging system, regardless of the extent of lymph node dissection. Patient counseling and adjuvant therapy decision‐making should benefit from use of the nomogram. Cancer 2005. © 2005 American Cancer Society.

6 January 2023 in Journal of Clinical Medicine
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Journal Article
Open access
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ZZZhou Zhou
Zhou Zhou
LOLaura Filiaquarta Ouboter
Laura Filiaquarta Ouboter
KPKoen Peeters
Koen Peeters
Lukas HawinkelsLukas Hawinkels
Lukas Hawinkels
FHFabian Holman
Fabian Holman
AMAndrea van der Meulen
Andrea van der Meulen
Perianal fistulas are defined as pathological connections between the anorectal canal and the perianal skin. Most perianal fistulas are cryptoglandular fistulas, which are thought to originate from infected anal glands. The remainder of the fistulas mainly arises as complications of Crohn’s disease (CD), trauma, or as a result of malignancies. Fistulas in CD are considered as a consequence of a chronic and transmural inflammatory process in the distal bowel and can, in some cases, even precede the diagnosis of CD. Although both cryptoglandular and CD-associated fistulas might look similar macroscopically, they differ considerably in their complexity, treatment options, and healing rate. Therefore, it is of crucial importance to differentiate between these two types of fistulas. In this review, the differences between CD-associated and cryptoglandular perianal fistulas in epidemiology, pathogenesis, and clinical management are discussed. Finally, a flow chart is provided for physicians to guide them when dealing with patients displaying their first episode of perianal fistulas.

31 March 2020 in Psycho-Oncology
Verified
Journal Article
Open access
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NVNina C. A. Vermeer
Nina C. A. Vermeer
MVMaxime J. M. van der Valk
Maxime J. M. van der Valk
HSHeleen S. Snijders
Heleen S. Snijders
HVHans F. A. Vasen
Hans F. A. Vasen
AHArthur Gerritsen van der Hoop
Arthur Gerritsen van der Hoop
KPKoen Peeters
Koen Peeters
Objective: This study aimed to assess psychological functioning, quality of life, and regret about screening after a positive fecal immunochemical test (FIT) and subsequent colonoscopy, and to evaluate changes over time.Methods: This is a prospective cohort study. Individuals aged 55 to 75 with a positive FIT that were referred for colonoscopy between July 2017 and November 2018, were invited to complete questionnaires related to psychological distress and health‐related quality of life at three predefined time points: before colonoscopy, after histopathology result notification, and after 6 months. Four questionnaires were used: the Psychological Consequences Questionnaire (PCQ), the six‐item Cancer Worry Scale (CWS), the Decision Regret Scale (DRS), and the 36‐item Short‐Form (SF‐36).Results: A total of 1066 participants out of 2151 eligible individuals were included. Patients with cancer showed a significant increase in psychological dysfunction (P = .01) and cancer worry (P = .008) after colonoscopy result notification, and a decline to pre‐colonoscopy measurements after 6 months. In the no‐cancer groups, psychological dysfunction and cancer worry significantly decreased over time (P < .05) but there was no ongoing decline. After 6 months, 17% of participants with no cancer experienced high level of cancer worry (CWS ≥ 10). Yet, only 5% reported high level of regret about screening participation (DRS > 25). A good global quality of life was reported in participants with no cancer.Conclusion: Some psychological distress remains up to 6 months after colonoscopy in participants who tested false‐positive in the Dutch bowel cancer screening program.

18 April 2024 in Cancers
Verified
Journal Article
Open access
PDF file
STSofieke Temmink
Sofieke Temmink
KPKoen Peeters
Koen Peeters
PNPer Johan Nilsson
Per Johan Nilsson
AMAnna Martling
Anna Martling
CVCornelis J.H. van de Velde
Cornelis J.H. van de Velde
Over the past decade, the treatment of rectal cancer has changed considerably. The implementation of TME surgery has, in addition to decreasing the number of local recurrences, improved surgical morbidity and mortality. At the same time, the optimisation of radiotherapy in the preoperative setting has improved oncological outcomes even further, although higher perineal infection rates have been reported. Radiotherapy regimens have evolved through the adjustment of radiotherapy techniques and fields, increased waiting intervals, and, for more advanced tumours, adding chemotherapy. Concurrently, imaging techniques have significantly improved staging accuracy, facilitating more precise selection of advanced tumours. Although chemoradiotherapy does lead to the downsizing and -staging of these tumours, a very clear effect on sphincter-preserving surgery and the negative resection margin has not been proven. Aiming to decrease distant metastasis and improve overall survival for locally advanced rectal cancer, systemic chemotherapy can be added to radiotherapy, known as total neoadjuvant treatment (TNT). High complete response rates, both pathological (pCR) and clinical (cCR), are reported after TNT. Patients who follow a Watch & Wait program after a cCR can potentially avoid surgical morbidity and colostomy. For both early and more advanced tumours, trials are now investigating optimal regimens in an attempt to offer organ preservation as much as possible. Multidisciplinary deliberation should include patient preference, treatment toxicity, and likelihood of end colostomy, but also the burden of intensive surveillance in a W&W program.