Kössler Thibaud

Dr. Thibaud Kössler

Médecin adjoint, responsible d’unité Oncologie


I am a senior consultant in medical oncology specialized in gastrointestinal cancer at the Geneva University Hospital (HUG). I hold a medical degree (MD) from the University of Geneva (2005) and a Ph.D. in genetics and epidemiology from the University of Cambridge (2009). After training at HUG and at Guy’s and St Thomas hospital in London, I received my certification as a specialist in Oncology (FMH) in 2018 and became consultant the same year. In 2019, I became head of Gastrointestinal Oncology Unit and chair of the Gastrointestinal Tumor Board. I am heavily involved in clinical research as a principal investigator in Phase I to III trials. My extensive knowledge in the field of colorectal cancer allowed me to design my own Phase II trial : PEMREC- NCT04109755. As a recognition of my expertise I became in 2019 co-chair of colorectal cancer Task Force at the European Organisation for Research and Treatment of Cancer (EORTC) and member of the scientific committee in the Swiss Group for Clinical Cancer Research (SAKK).

My scientific interests focus on understanding the complexity of the colorectal cancer microenviroment with the ultimate aim to discover druggable targets and therefore improve treatment options for patients affected by this disease. Endowed with a departmental funding, I have created in 2021 my laboratory ( together with Dr. Claudia Corro, Ph.D.. Along with running innovative clinical trials, my group is generating a single-cell atlas of colorectal cancer cells and their surrounding immune and stromal populations in order to explore functional states, spatial interaction, and cell-specific transcriptional changes related to specific therapeutic interventions. This involves the use of state-of-the-art techniques such as single-cell RNA sequencing, advanced flow cytometry and spatial multiplexed techniques as well as in vitro and in vivo assays. Overall, the laboratory has three main goals, a) predicting treatment responses using untreated patients’ samples, b) discovering new potential therapeutic targets which will have been revealed after treatment, c) developing mouse models able to recapitulate human response and test novel therapeutic strategies.

Together with my team, we have a good expertise in transcriptomic and multiplex immunofluorescence analyses. We are experts in murine colonoscopy procedure and possess the only available device at UNIGE to perform endoscopyguided injection of injection of tumor cells, organoids, and other substances (i.e. tamoxifen for conditional mouse models, therapeutic compounds, etc.) locally into the colon and rectal epithelium of mice. This minimally invasive procedure offers the possibility to investigate therapeutic interventions in the original tumor microenvironment (TME), which facilitates local T cell infiltration and tissue vascularization, to monitor tumor growth within the GI track without scarifying animals as well as to perform intra-individual follow-up sampling for further analysis.


  • Study protocol of a phase II study to evaluate safety and efficacy of neo-adjuvant pembrolizumab and radiotherapy in localized rectal cancer. Claudia Corrò et al. BMC cancer 2022
  • Debating Pros and Cons of Total Neoadjuvant Therapy in Rectal Cancer. Sclafani F, Corrò C, Koessler T. Cancers. 2021
  • Emerging Trends for Radio-Immunotherapy in Rectal Cancer. Corrò C, Dutoit V, Koessler T. Cancers. 2021
  • Cumulative impact of common genetic variants and other risk factors on colorectal cancer risk in 42,103 individuals. Dunlop MG et al. Gut. 2013
  • Common variants in mismatch repair genes and risk of colorectal cancer. Koessler T et al. Gut. 2008

Link to full publication list (e.g. Google Scholar): ORCID: 0000-0001-9196-9076