Sandor Schokker

Mr. Sandor Schokker

orcid

Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

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

Representative Publications

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27 January 2021 in Clinical Cancer Research
Verified
Journal Article
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TETom Van den Ende
Tom Van den Ende
NCNicolien C. de Clercq
Nicolien C. de Clercq
Mark I. van Berge HenegouwenMark I. van Berge Henegouwen
Mark I. van Berge Henegouwen
SGSuzanne S. Gisbertz
Suzanne S. Gisbertz
EGE.D. Geijsen
E.D. Geijsen
HLHanneke Van Laarhoven
Hanneke Van Laarhoven
Purpose: The CROSS trial established neoadjuvant chemoradiotherapy (nCRT) for patients with resectable esophageal adenocarcinoma (rEAC). In the PERFECT trial, we investigated the feasibility and efficacy of nCRT combined with programmed-death ligand-1 (PD-L1) inhibition for rEAC. Patients and Methods: Patients with rEAC received nCRT according to the CROSS regimen combined with five cycles of atezolizumab (1,200 mg). The primary endpoint was the feasibility of administering five cycles of atezolizumab in ≥75% patients. A propensity score–matched nCRT cohort was used to compare pathologic response, overall survival, and progression-free survival. Exploratory biomarker analysis was performed on repeated tumor biopsies. Results: We enrolled 40 patients of whom 85% received all cycles of atezolizumab. Immune-related adverse events of any grade were observed in 6 patients. In total, 83% proceeded to surgery. Reasons for not undergoing surgery were progression (n = 4), patient choice (n = 2), and death (n = 1). The pathologic complete response rate was 25% (10/40). No statistically significant difference in response or survival was found between the PERFECT and the nCRT cohort. Baseline expression of an established IFNγ signature was higher in responders compared with nonresponders (P = 0.043). On-treatment nonresponders showed either a high number of cytotoxic lymphocytes (CTL) with a transcriptional signature consistent with expression of immune checkpoints, or a low number of CTLs. Conclusions: Combining nCRT with atezolizumab is feasible in patients with rEAC. On the basis of our exploratory biomarker study, future studies are necessary to elucidate the potential of neoadjuvant immunotherapy in patient subgroups. See related commentary by Catenacci, p. 3269

1 May 2014 in JACC
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Journal Article
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WZWillemijn M.H. Zijlstra
Willemijn M.H. Zijlstra
JDJohannes Menno Douwes
Johannes Menno Douwes
BRBerman Rosenzweig
Berman Rosenzweig
SSSandor Schokker
Sandor Schokker
UKUsha Krishnan
Usha Krishnan
RBRolf M.F. Berger
Rolf M.F. Berger

24 July 2019 in International Journal of Cancer
Verified
Journal Article
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MSMarin Strijker
Marin Strijker
ESEline C. Soer
Eline C. Soer
MPMatteo de Pastena
Matteo de Pastena
ACAafke Creemers
Aafke Creemers
ABAlberto Balduzzi
Alberto Balduzzi
HLHanneke Van Laarhoven
Hanneke Van Laarhoven
Circulating tumor DNA (ctDNA) is assumed to reflect tumor burden and has been suggested as a tool for prognostication and follow‐up in patients with metastatic pancreatic ductal adenocarcinoma (mPDAC). However, the prognostic value of ctDNA and its relation with tumor burden has yet to be substantiated, especially in mPDAC. In this retrospective analysis of prospectively collected samples, cell‐free DNA from plasma samples of 58 treatment‐naive mPDAC patients was isolated and sequenced using a custom‐made pancreatobiliary NGS panel. Pathogenic mutations were detected in 26/58 (44.8%) samples. Cross‐check with droplet digital PCR showed good agreement in Bland–Altman analysis (p = 0.217, nonsignificance indicating good agreement). In patients with liver metastases, ctDNA was more frequently detected (24/37, p < 0.001). Tumor volume (3D reconstructions from imaging) and ctDNA variant allele frequency (VAF) were correlated (Spearman's ρ = 0.544, p < 0.001). Median overall survival (OS) was 3.2 (95% confidence interval [CI] 1.6–4.9) versus 8.4 (95% CI 1.6–15.1) months in patients with detectable versus undetectable ctDNA (p = 0.005). Both ctDNA VAF and tumor volume independently predicted OS after adjustment for carbohydrate antigen 19.9 and treatment regimen (hazard ratio [HR] 1.05, 95% CI 1.01–1.09, p = 0.005; HR 1.00, 95% CI 1.01–1.05, p = 0.003). In conclusion, our study showed that ctDNA detection rates are higher in patients with larger tumor volume and liver metastases. Nevertheless, measurements may diverge and, thus, can provide complementary information. Both ctDNA VAF and tumor volume were strong predictors of OS.

10 February 2020 in Journal of Clinical Oncology
Verified
Journal Article
Closed access
CSCharlotte I. Stroes
Charlotte I. Stroes
SSSandor Schokker
Sandor Schokker
ACAafke Creemers
Aafke Creemers
RMRemco J. Molenaar
Remco J. Molenaar
MHMaarten C.C.M. Hulshof
Maarten C.C.M. Hulshof
HLHanneke Van Laarhoven
Hanneke Van Laarhoven
PURPOSE: Approximately 15% to 43% of esophageal adenocarcinomas (EACs) are human epidermal growth factor receptor 2 (HER2) positive. Because dual-agent HER2 blockade demonstrated a survival benefit in breast cancer, we conducted a phase II feasibility study of trastuzumab and pertuzumab added to neoadjuvant chemoradiotherapy (nCRT) in patients with EAC. PATIENTS AND METHODS: Patients with resectable HER2-positive EAC received standard nCRT with carboplatin and paclitaxel and 41.4 Gy of radiotherapy, with 4 mg/kg of trastuzumab on day 1, 2 mg/kg per week during weeks 2 to 6, and 6 mg/kg per week during weeks 7, 10, and 13 and 840 mg of pertuzumab every 3 weeks. The primary end point was feasibility, defined as ≥ 80% completion of treatment with both trastuzumab and pertuzumab. An exploratory comparison of survival with a propensity score–matched cohort receiving standard nCRT was performed, as were exploratory pharmacokinetic and biomarker analyses. RESULTS: Of the 40 enrolled patients (78% men; median age, 63 years), 33 (83%) completed treatment with trastuzumab and pertuzumab. No unexpected safety events were observed. R0 resection was achieved in all patients undergoing surgery, with pathologic complete response in 13 patients (34%). Three-year progression-free and overall survival (OS) were 57% and 71%, respectively (median follow-up, 32.1 months). Compared with the propensity score–matched cohort, a significantly longer OS was observed with HER2 blockade (hazard ratio, 0.58; 95% CI, 0.34 to 0.97). Results of pharmacokinetic analysis and activity on [18F]fluorodeoxyglucose positron emission tomography scans did not correlate with survival or pathologic response. Patients with HER2 3+ overexpression or growth factor receptor–bound protein 7 (Grb7) –positive tumors at baseline demonstrated significantly better survival ( P = .007) or treatment response ( P = .016), respectively. CONCLUSION: Addition of trastuzumab and pertuzumab to nCRT in patients with HER2-positive EAC is feasible and demonstrates potentially promising activity compared with historical controls. HER2 3+ overexpression and Grb7 positivity are potentially predictive for survival and treatment response, respectively.

28 June 2019 in JNCI: Journal of the National Cancer Institute
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Journal Article
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JKJessy Joy van Kleef
Jessy Joy van Kleef
EVEmil ter Veer
Emil ter Veer
HBHéctor G van Den Boorn
Héctor G van Den Boorn
SSSandor Schokker
Sandor Schokker
LNLok Lam Ngai
Lok Lam Ngai
HLHanneke Van Laarhoven
Hanneke Van Laarhoven
Background: Palliative systemic therapy can prolong life and reduce tumor-related symptoms for patients with advanced esophagogastric cancer. However, side effects of treatment could negatively affect health-related quality of life (HRQoL). Our aim was to review the literature and conduct a meta-analysis to examine the effect of palliative systemic therapy on HRQoL.Methods: EMBASE, Medline, and Central were searched for phase II/III randomized controlled trials until April 2018 investigating palliative systemic therapy and HRQoL. Meta-analysis was performed on baseline and follow-up summary values of global health status (GHS) and other European Organisation for Research and Treatment of Cancer scales. A clinically relevant change and difference of 10 points (scale 0–100) was set to assess the course of HRQoL over time within treatment arms as well as between arms.Results: We included 43 randomized controlled trials (N = 13 727 patients). In the first-line and beyond first-line treatment setting, pooled baseline GHS mean estimates were 54.6 (95% confidence interval = 51.9 to 57.3) and 57.9 (95% confidence interval = 55.7 to 60.1), respectively. Thirty-nine (81.3%) treatment arms showed a stable GHS over the course of time. Anthracycline-based triplets, fluoropyrimidine-based doublets without cisplatin, and the addition of trastuzumab to chemotherapy were found to have favorable HRQoL outcomes. HRQoL benefit was observed for taxane monotherapy and several targeted agents over best supportive care beyond first line.Conclusions: Patients reported impaired GHS at baseline and generally remained stable over time. Anthracycline-based triplets and fluoropyrimidine-based doublets without cisplatin may be preferable first-line treatment options regarding HRQoL for HER2-negative disease. Taxanes and targeted agents could provide HRQoL benefit beyond first line compared with best supportive care.

1 November 2018 in European Journal of Cancer
Verified
Journal Article
Closed access
EVEmil ter Veer
Emil ter Veer
JKJessy Joy van Kleef
Jessy Joy van Kleef
SSSandor Schokker
Sandor Schokker
SWStephanie O. van der Woude
Stephanie O. van der Woude
MLMarety Laarman
Marety Laarman
HLHanneke Van Laarhoven
Hanneke Van Laarhoven