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Lymphatic Progression eXplorer

Collecting, sharing, and visualizing data on the lymphatic progression patterns in head and neck cancer.

The Goal

Head & neck squamous cell carcinomas (HNSCCs) frequently metastasize through the lymphatic network. Hence, radiation oncologists often have to decide whether to include clinically healthy lymph node levels into the clinical target volume (CTV). Similarly, surgeons have to decide which lymph node levels to resect.

To aid them in their decision, the prevalence of metastatic involvement for HNSCC has been reported in numerous publications (1,2,3,4,5). However, the detailed patterns of progression, i.e. correlations between frequently metastatic lymph node levels as well as primary tumor characteristics, remain insufficiently quantified. As a consequence, clinical guidelines on elective CTV definition are mostly based on prevalence of lymph node level involvement. Data that would allow for further personalization of CTV definition based on a patient's individual state of tumor progression is not available.

To tackle this, we extracted a dataset of 287 oropharyngal SCC patients treated at the University Hospital Zürich. We report on a patient-individual basis the patterns of lymphatic metastatic progression together with primary tumor and patient risk factors. This dataset has been described and published in great detail.

To make this data more accessible and especially easier to understand and draw conclusions from, we developed this web-based interface and in particular the data explorer dashboard where one can interact with the underlying data in a more intuitive way.

More recently, we have received the underlying data of a study published by Bauwens et al. via communications with Prof. Vincent Grégoire. Their dataset is now also freely explorable in LyProX. Beyond that, we are in the process of visualizing even more datasets from other institutions in the near future.


Currently, the functions that have been implemented in this web-based application are as follows: Anyone can freely

  • view the details of every patient in the two public datasets in the "Patients" tab
  • export and download the two public datasets as CSV files via the "Datasets" tab
  • visualize the correlations in the patterns of lymphatic progression in an interactive dashboard under the "Data Explorer" tab
  • choose a model and get predictions for the risk of microscopic involvement, given a personalized diagnosis in the "Risk Predictor" tab.


As hinted at earlier, more data is planned to be released. We have received another two additional datasets of detailed lymphatic progression patterns that we will publish in the coming months. We will also collect more data at our own institution, the University Hospital Zurich, that we will share on LyProX. And we have signed data sharing agreements or are in discussions with yet another two research groups. The goal is to have a multi-centric, multinational dataset of several thousand patients, each with detailed information on their lymphatic involvement patterns.

In the long term, we would also like to extend the functionality of the interface to allow our collaborators and us to directly enter patient data into LyProX. That way, multiple institutions and researchers could collectively add data in a seamless manner.

If you are interested in our project and would like to learn more, and/or contribute to it in some form, feel free to reach out to us via an email to

Our Publications

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Roman Ludwig, Jean-Marc Hoffmann, Bertrand Pouymayou, Martina Broglie Däppen, Grégoire Morand, Matthias Guckenberger, Vincent Grégoire, Panagiotis Balermpas, Jan Unkelbach
Detailed patient-individual reporting of lymph node involvement in oropharyngeal squamous cell carcinoma with an online interface
Radiotherapy and Oncology 169, 1-7 (2022) 10.1016/j.radonc.2022.01.035

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Roman Ludwig, Jean-Marc Hoffmann, Bertrand Pouymayou, Grégoire Morand, Martina Broglie Däppen, Matthias Guckenberger, Vincent Grégoire, Panagiotis Balermpas, Jan Unkelbach
A dataset on patient-individual lymph node involvement in oropharyngeal squamous cell carcinoma
Data in Brief 43, 108345 (2022) 10.1016/j.dib.2022.108345

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Laurence Bauwens, Aline Baltres, Danny-Joe Fiani, Philippe Zrounba, Guillaume Buiret, Bertrand Fleury, Nazim Benzerdjeb, Vincent Grégoire
Prevalence and distribution of cervical lymph node metastases in HPV-positive and HPV-negative oropharyngeal squamous cell carcinoma
Radiotherapy and Oncology 157, 122-129 (2021) 10.1016/j.radonc.2021.01.028

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Roman Ludwig, Bertrand Pouymayou, Panagiotis Balermpas, Jan Unkelbach
A hidden Markov model for lymphatic tumor progression in the head and neck
Scientific Reports 11, 12261 (2021) 10.1038/s41598-021-91544-1

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Bertrand Pouymayou, Panagiotis Balermpas, Oliver Riesterer, Matthias Guckenberger, Jan Unkelbach
A Bayesian network model of lymphatic tumor progression for personalized elective CTV definition in head and neck cancers
Physics in Medicine & Biology 64, 165003 (2019) 10.1088/1361-6560/ab2a18

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Jan Unkelbach, Thomas Bortfeld, Carlos E. Cardenas, Vincent Gregoire, Wille Hager, Ben Heijmen, Robert Jeraj, Stine S. Korreman, Roman Ludwig, Bertrand Pouymayou, Nadya Shusharina, Jonas Söderberg, Iuliana Toma-Dasu, Esther G. C. Troost, Eliana Vasquez Osorio
The role of computational methods for automating and improving clinical target volume definition
Radiotherapy and Oncology 153, 15-25 (2020) 10.1016/j.radonc.2020.10.002