Stefan Rieken

Stefan Rieken


Research Focus & Metrics

Academic Career Length

17Years (2010-Present)

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

Representative Publications

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5 January 2018 in Radiation Oncology
Verified
Journal Article
Open access
PDF file
YDYing Dai
Ying Dai
QWQuanxiang Wei
Quanxiang Wei
CSChristian Schwager
Christian Schwager
JHJanina Hanne
Janina Hanne
CZCheng Zhou
Cheng Zhou
AAAmir Abdollahi
Amir Abdollahi
Patients with Echinoderm microtubule-associated protein-like 4 (EML4)-anaplastic lymphoma kinase (ALK) positive lung cancer are sensitive to ALK-kinase inhibitors. TAE684 is a potent second generation ALK inhibitor that overcomes Crizotinib resistance. Radiotherapy is an integral therapeutic component of locally advanced lung cancer. Therefore, we sought to investigate the effects of combined radiotherapy and ALK-inhibition via TAE684 in ALK-positive vs. wild type lung cancer cells. Human non-small cell lung cancer (NSCLC) cell lines harboring wild-type ALK (A549), EML4-ALK translocation (H3122) and murine Lewis Lung Cancer (LLC) cells were investigated. Cells were irradiated with 1–4 Gy X-Rays (320 keV) and carbon ions (Spread-out Bragg Peak, SOBP (245.4–257.0 MeV/u)) at Heidelberg Ion Therapy center. TAE684 was administered at the dose range 0–100 nM. Clonogenic survival, proliferation and apoptosis via caspase 3/7 expression level were assessed in all three cell lines using time-lapse live microscopy. TAE684 inhibited the proliferation of H3122 cells in a dose-dependent manner with a half maximal inhibitory concentration (IC50) of ~ 8.2 nM. However, A549 and LLC cells were relatively resistant to TAE684 and IC50 was not reached at concentrations tested (up to 100 nM) in proliferation assay. The antiproliferative effect of TAE684 was augmented by radiotherapy in H3122 cells. TAE684 significantly sensitized H3122 cells to particle therapy with carbon ions (sensitizer enhancement ratio ~1.61, p < 0.05). Caspase 3/7 activity was evidently enhanced after combination therapy in H3122 cells. This is the first report demonstrating synergistic effects of combined TAE684 and radiotherapy in EML4-ALK positive lung cancer cells. In addition to conventional photon radiotherapy, ALK-inhibition also enhanced the effects of particle irradiation using carbon ions. Our data indicate beneficial effects of combined ALK-inhibition and radiotherapy in treatment of this distinct subpopulation of NSCLC that warrant further evaluation.

13 September 2011 in Radiation Oncology
Verified
Journal Article
Open access
PDF file
SCStephanie Combs
Stephanie Combs
SRStefan Rieken
Stefan Rieken
WWWolfgang Wick
Wolfgang Wick
AAAmir Abdollahi
Amir Abdollahi
ADAndreas von Deimling
Andreas von Deimling
CHChristian Hartmann
Christian Hartmann
A group of 160 patients with primary glioblastoma treated with radiotherapy and temozolomide was analyzed for the impact of O6-methly-guanly-methyl-transferase (MGMT)-promoter methylation as well as isocitrate dehydrogenase (IDH)1-mutational status. Unexpectedly, overall survival or progression-free survival were not longer in the group with methylated MGMT-promoter as compared to patients without that methylation. IDH-1 mutations were significantly associated with increased overall survival.

6 September 2010 in BMC Cancer
Verified
Journal Article
Open access
PDF file
SCStephanie Combs
Stephanie Combs
MKMeinhard Kieser
Meinhard Kieser
SRStefan Rieken
Stefan Rieken
DHDaniel Habermehl
Daniel Habermehl
OJOliver Jäkel
Oliver Jäkel
JDJürgen Debus
Jürgen Debus
Treatment standard for patients with primary glioblastoma (GBM) is combined radiochemotherapy with temozolomide (TMZ). Radiation is delivered up to a total dose of 60 Gy using photons. Using this treatment regimen, overall survival could be extended significantly however, median overall survival is still only about 15 months.

2 March 2012 in Radiation Oncology
Verified
Journal Article
Open access
PDF file
DHDaniel Habermehl
Daniel Habermehl
KKKerstin Kessel
Kerstin Kessel
TWThomas Welzel
Thomas Welzel
HHHolger Hof
Holger Hof
AAAmir Abdollahi
Amir Abdollahi
SCStephanie Combs
Stephanie Combs
To evaluate efficacy and secondary resectability in patients with locally advanced pancreatic cancer (LAPC) treated with neoadjuvant chemoradiotherapy (CRT). A total of 215 patients with locally advanced pancreatic cancer were treated with chemoradiation at a single institution. Radiotherapy was delivered with a median dose of 52.2 Gy in single fractions of 1.8 Gy. Chemotherapy was applied concomitantly as gemcitabine (GEM) at a dose of 300 mg/m2 weekly, followed by adjuvant cycles of full-dose GEM (1000 mg/m2). After neoadjuvant CRT restaging was done to evaluate secondary resectability. Overall and disease-free survival were calculated and prognostic factors were estimated. After CRT a total of 26% of all patients with primary unresectable LAPC were chosen to undergo secondary resection. Tumour free resection margins could be achieved in 39.2% (R0-resection), R1-resections were seen in 41.2%, residual macroscopic tumour in 11.8% (R2) and in 7.8% resection were classified as Rx. Patients with complete resection after CRT showed a significantly increased median overall survival (OS) with 22.1 compared to 11.9 months in non-resected patients. Median OS and disease-free survival (DFS) of all patients were 12.3 and 8.1 months respectively. In most cases the first site of disease progression was systemic with hepatic (52%) and peritoneal (36%) metastases. A high percentage of patients with locally advanced pancreatic cancer can undergo secondary resection after gemcitabine-based chemoradiation and has a relative long-term prognosis after complete resection.

6 October 2010 in BMC Cancer
Verified
Journal Article
Open access
PDF file
SCStephanie Combs
Stephanie Combs
IBIris Burkholder
Iris Burkholder
LELutz Edler
Lutz Edler
SRStefan Rieken
Stefan Rieken
DHDaniel Habermehl
Daniel Habermehl
JDJürgen Debus
Jürgen Debus
Treatment of patients with recurrent glioma includes neurosurgical resection, chemotherapy, or radiation therapy. In most cases, a full course of radiotherapy has been applied after primary diagnosis, therefore application of re-irradiation has to be applied cauteously. With modern precision photon techniques such as fractionated stereotactic radiotherapy (FSRT), a second course of radiotherapy is safe and effective and leads to survival times of 22, 16 and 8 months for recurrent WHO grade II, III and IV gliomas.

1 December 2013 in Radiotherapy and Oncology
Verified
Journal Article
Closed access
SRStefan Rieken
Stefan Rieken
DHDaniel Habermehl
Daniel Habermehl
FGFrederik L. Giesel
Frederik L. Giesel
CHChristoph Hoffmann
Christoph Hoffmann
UBUte Burger
Ute Burger
SCStephanie Combs
Stephanie Combs