Christoph Oehler

Dr. Christoph Oehler

Department of Radiation Oncology, Kantonsspital Winterthur, Winterthur, Switzerland

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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23 May 2010 in Radiation Oncology
Verified
Journal Article
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SPSawyna Provencher
Sawyna Provencher
COChristoph Oehler
Christoph Oehler
SLSophie Lavertu
Sophie Lavertu
MJMarjory Jolicoeur
Marjory Jolicoeur
BFBernard Fortin
Bernard Fortin
DDDavid Donath
David Donath
To evaluate quality of life (QOL) and outcome of patients with anal carcinoma treated with short split-course chemoradiation (CRT). From 1991 to 2005, 58 patients with anal cancer were curatively treated with CRT. External beam radiotherapy (52 Gy/26 fractions) with elective groin irradiation (24 Gy) was applied in 2 series divided by a median gap of 12 days. Chemotherapy including fluorouracil and Mitomycin-C was delivered in two sequences. Long-term QOL was assessed using the site-specific EORTC QLQ-CR29 and the global QLQ-C30 questionnaires. Five-year local control, colostomy-free survival, and overall survival were 78%, 94% and 80%, respectively. The global QOL score according to the QLQ-C30 was good with 70 out of 100. The QLQ-CR29 questionnaire revealed that 77% of patients were mostly satisfied with their body image. Significant anal pain or fecal incontinence was infrequently reported. Skin toxicity grade 3 or 4 was present in 76% of patients and erectile dysfunction was reported in 100% of male patients. Short split-course CRT for anal carcinoma seems to be associated with good local control, survival and long-term global QOL. However, it is also associated with severe acute skin toxicity and sexual dysfunction. Implementation of modern techniques such as intensity-modulated radiation therapy (IMRT) might be considered to reduce toxicity.

11 November 2014 in Radiation Oncology
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Journal Article
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COChristoph Oehler
Christoph Oehler
SLStephanie Lang
Stephanie Lang
PDPeter Dimmerling
Peter Dimmerling
CBChristian Bolesch
Christian Bolesch
SKStephan Kloeck
Stephan Kloeck
DZDaniel R Zwahlen
Daniel R Zwahlen
To evaluate PTV margins for hypofractionated IGRT of prostate comparing kV/kV imaging or CBCT. Between 2009 and 2012, 20 patients with low- (LR), intermediate- (IR) and high-risk (HR) prostate cancer were treated with VMAT in supine position with fiducial markers (FM), endorectal balloon (ERB) and full bladder. CBCT’s and kV/kV imaging were performed before and additional CBCT’s after treatment assessing intra-fraction motion. CTVP for 5 patients with LR and CTVPSV for 5 patients with IR/HR prostate cancer were contoured independently by 3 radiation oncologists using MRI. The van Hark formula (PTV margin =2.5Σ +0.7σ) was applied to calculate PTV margins of prostate/seminal vesicles (P/PSV) using CBCT or FM. 172 and 52 CBCTs before and after RT and 507 kV/kV images before RT were analysed. Differences between FM in CBCT or in planar kV image pairs were below 1 mm. Accounting for both random and systematic uncertainties anisotropic PTV margins were 5-8 mm for P (LR) and 6-11 mm for PSV (IR/HR). Random uncertainties like intra-fraction and inter-fraction (setup) uncertainties were of similar magnitude (0.9-1.4 mm). Largest uncertainty was introduced by CTV delineation (LR: 1-2 mm, IR/HR: 1.6-3.5 mm). Patient positioning using bone matching or ERB-matching resulted in larger PTV margins. For IGRT CBCT or kV/kV-image pairs with FM are interchangeable in respect of accuracy. Especially for hypofractionated RT, PTV margins can be kept in the range of 5 mm or below if stringent daily IGRT, ideally including prostate tracking, is applied. MR-based CTV delineation optimization is recommended.

30 August 2016 in Radiation Oncology
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Journal Article
Open access
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MZMichel Zimmermann
Michel Zimmermann
COChristoph Oehler
Christoph Oehler
UMUlrich Mey
Ulrich Mey
Pirus GhadjarPirus Ghadjar
Pirus Ghadjar
DMDaniel Rudolf Zwahlen, MBA
Daniel Rudolf Zwahlen, MBA
Two large, recently published observational studies demonstate a clear down-trend in the use of radiotherapy (RT) over the last 15 years, both in the setting of follicular and diffuse large B-cell lymphoma. This change of practice might have a negative impact on clinical outcome. Even within the context of modern systemic therapy, omission of RT translates not only into a shorter progression-free survival (PFS), but also into a worse overall survival (OS). RT should therefore remain standard practice. This short review is aiming to summarize current guidelines and the best evidence available in the management of non-Hodgkin’s lymphoma. Potentially practice changing, ongoing trials will be highlighted.

16 February 2011 in BMC Cancer
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Journal Article
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ABAndré O von Bueren
André O von Bueren
COChristoph Oehler
Christoph Oehler
TSTarek Shalaby
Tarek Shalaby
KHKatja von Hoff
Katja von Hoff
Martin PruschyMartin Pruschy
Martin Pruschy
MGMichael A Grotzer
Michael A Grotzer
To study whether and how c-MYC expression determines response to radio- and chemotherapy in childhood medulloblastoma (MB). We used DAOY and UW228 human MB cells engineered to stably express different levels of c-MYC, and tested whether c-MYC expression has an effect on radio- and chemosensitivity using the colorimetric 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium inner salt (MTS) assay, clonogenic survival, apoptosis assays, cell cycle analysis, and western blot assessment. In an effort to validate our results, we analyzed c-MYC mRNA expression in formalin-fixed paraffin-embedded tumor samples from well-documented patients with postoperative residual tumor and compared c-MYC mRNA expression with response to radio- and chemotherapy as examined by neuroradiological imaging. In DAOY - and to a lesser extent in UW228 - cells expressing high levels of c-MYC, the cytotoxicity of cisplatin, and etoposide was significantly higher when compared with DAOY/UW228 cells expressing low levels of c-MYC. Irradiation- and chemotherapy-induced apoptotic cell death was enhanced in DAOY cells expressing high levels of c-MYC. The response of 62 of 66 residual tumors was evaluable and response to postoperative radio- (14 responders (CR, PR) vs. 5 non-responders (SD, PD)) or chemotherapy (23 CR/PR vs. 20 SD/PD) was assessed. c-MYC mRNA expression was similar in primary MB samples of responders and non-responders (Mann-Whitney U test, p = 0.50, ratio 0.49, 95% CI 0.008-30.0 and p = 0.67, ratio 1.8, 95% CI 0.14-23.5, respectively). c-MYC sensitizes MB cells to some anti-cancer treatments in vitro. As we failed to show evidence for such an effect on postoperative residual tumors when analyzed by imaging, additional investigations in xenografts and larger MB cohorts may help to define the exact function of c-MYC in modulating response to treatment.

15 May 2024 in Cancers
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Journal Article
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David BenzaquenDavid Benzaquen
David Benzaquen
YLYaacov R Lawrence
Yaacov R Lawrence
DTDaniel Taussky
Daniel Taussky
DMDaniel Rudolf Zwahlen, MBA
Daniel Rudolf Zwahlen, MBA
COChristoph Oehler
Christoph Oehler
ACAmbroise Champion
Ambroise Champion
Introduction: Crosstalk occurs between nerve and cancer cells. These interactions are important for cancer homeostasis and metabolism. Nerve cells influence the tumor microenvironment (TME) and participate in metastasis through neurogenesis, neural extension, and axonogenesis. We summarized the past and current literature on the interaction between nerves and cancer, with a special focus on pancreatic ductal adenocarcinoma (PDAC), prostate cancer (PCa), and the role of the nerve growth factor (NGF) in cancer. Materials/Methods: We reviewed PubMed and Google Scholar for the relevant literature on the relationship between nerves, neurotrophins, and cancer in general and specifically for both PCa and PDAC. Results: The NGF helped sustain cancer cell proliferation and evade immune defense. It is a neuropeptide involved in neurogenic inflammation through the activation of several cells of the immune system by several proinflammatory cytokines. Both PCa and PDAC employ different strategies to evade immune defense. The prostate is richly innervated by both the sympathetic and parasympathetic nerves, which helps in both growth control and homeostasis. Newly formed autonomic nerve fibers grow into cancer cells and contribute to cancer initiation and progression through the activation of β-adrenergic and muscarinic cholinergic signaling. Surgical or chemical sympathectomy prevents the development of prostate cancer. Beta-blockers have a high therapeutic potential for cancer, although current clinical data have been contradictory. With a better understanding of the beta-receptors, one could identify specific receptors that could have an effect on prostate cancer development or act as therapeutic agents. Conclusion: The bidirectional crosstalk between the nervous system and cancer cells has emerged as a crucial regulator of cancer and its microenvironment. Denervation has been shown to be promising in vitro and in animal models. Additionally, there is a potential relationship between cancer and psychosocial biology through neurotransmitters and neurotrophins.

30 May 2017 in Acta Oncologica
Verified
Journal Article
Open access
MZMichel Zimmermann
Michel Zimmermann
JBJürgen Beer
Jürgen Beer
Stephan BodisStephan Bodis
Stephan Bodis
RMRoger von Moos
Roger von Moos
VVVasiliki Vlachopoulou
Vasiliki Vlachopoulou
COChristoph Oehler
Christoph Oehler
Background: To evaluate local control (LC), survival and toxicity in anal cancer patients treated with intensity-modulated radiation therapy (IMRT) and concurrent chemotherapy at a single institution. Material and methods: From August 2010 to May 2015, 26 patients were treated at our institution with IMRT and concurrent 5-fluorouracil/mitomycin-C (5-FU/MMC) for localized squamous cell carcinoma of the anal canal (SCCAC). Radiotherapy (RT) with 50.4–60 Gy was delivered with a sequential boost in 31%, and a simultaneous-integrated boost (SIB-IMRT) in 69% of cases. Initial staging was based on PET-CT and MRI. Clinical measures of interest were the influence of PET-CT on staging and treatment planning, LC, disease free survival (DFS), overall survival (OS), colostomy free survival (CFS) and toxicities. Results: Median age was 61 years, 22 patients (85%) were female, and no patient was HIV-positive. The proportion of patients with stage I, II, IIIA and IIIB disease was 15%, 35%, 23% and 27%, respectively. PET-CT modified the extent of nodal disease in 9/23 cases (39%) and lead to major changes in treatment planning in 4/23 patients (17%). MRI was more accurate at identifying T4 disease. RT was delivered at full dose in 26 patients (100%) and chemotherapy in 22/26 patients (85%). Two patients (7.7%) required RT breaks. Median follow-up was 35 months [IQR: 19–52]. The 2-year LC, DFS, OS and CFS were 100%, 100%, 100% and 92%. Acute grade ≥3 dermatitis and diarrhea occurred in 73% and 8% of cases, respectively. Grade 3–4 neutropenia was seen in 10/23 patients (43%). Four patients (15%) developed chronic grade 2 GI toxicity. Conclusions: PET-CT provided additional information leading to major changes in treatment planning for 17% of patients. Considering our excellent outcomes, routine use of PET-CT as standard staging modality and IMRT planning procedure appears justified for patients with SCCAC.