How is a tumor structured, and how does it develop? By zooming in on the molecular properties of a tumor, UMC Utrecht’s new professor Lodewijk Brosens wants to improve the treatment of rare cancers in the gastrointestinal tract and pancreas.
Neuroendocrine tumours (NETs) arise from cells that can make hormones. They can occur in various places in the body, but often originate in the gastrointestinal tract and pancreas. These so-called ‘gastroenteropancreatic neuroendocrine’ tumours are relatively rare. Some grow slowly, while others behave much more aggressively. It is precisely this difference that sometimes makes the diagnosis and choice of treatment difficult.
Clinical pathologist Lodewijk Brosens wants to change that. He specializes in tumors of the gastrointestinal tract and pancreas and in neuroendocrine tumors.
He has been appointed professor of ‘Pathology of gastrointestinal (neuroendocrine) tumors’ as of 1 November 2026. “My personal mission as a clinical pathologist is to make the most accurate and personal diagnosis possible for each patient. This forms the basis for the best possible treatment for each individual patient.”
“My ambition is that new developments in pathology will lead to better patient care”
Lodewijk and his team focus on the biology of tumors: how do they develop, what are they made of, and how and why do they grow? Biomarkers can be discovered from this research. These are measurable characteristics of a tumor that help, for example, to make a better diagnosis or predict the aggressiveness of a tumor. Think, for example, of proteins or genetic mutations in the tumor. Lodewijk’s new chair focuses on the development, testing and application of such biomarkers in daily patient care.
“As a pathologist, we look into a patient’s tissue. Such as a biopsy taken by an MDL doctor or radiologist, or a tumor removed by a surgeon. In this tissue, we can look at certain proteins, or at changes in the DNA (the biomarkers) that help us make the correct diagnosis and say something about the expected behavior of a tumor,” explains Lodewijk.
Knowledge about biomarkers is important because doctors are regularly faced with a complicated choice. Due to the increase in imaging, such as the MRI, CT and PET scan, tumors are increasingly discovered by chance and at an early stage. But not every (small) tumor will behave the same. Surgery may be necessary, but it also involves risks.
If it is easier to predict which tumor will become aggressive, doctors can tailor treatment more accurately to this. This helps to prevent both too little and too much treatment. Because then intensive treatments only have to be used when they are really needed. This is better for the patient, and also relieves the burden on healthcare as a whole. That is why, for example, it is now decided not to remove a neuroendocrine tumor in the pancreas when it is smaller than two centimeters.
“However, some small tumors are aggressive, and you want to operate on them. In the biopsy taken by an MDL doctor, we look for biomarkers that allow us to recognize these small but aggressive tumors.”
For Lodewijk, his work always starts with the individual patient. He wants to be able to understand and predict for each patient which treatment suits him/her best. “In doing so, I want to contribute to the most appropriate treatment, greater chances of survival and a better quality of life,” he says.
Pathology plays an important role in ‘personalized medicine’. Clinical pathologists examine tissue and cells to determine which tumour it is. Lodewijk and his team combine this diagnosis with research into the specific genetic and molecular properties of tumors. Discoveries from the laboratory eventually find their way to the consulting room via new biomarker tests that the pathologist performs on the tumor tissue of patients.
Lodewijk’s new chair is part of the Oncology theme of UMC Utrecht. He has been working as a pathologist at UMC Utrecht since 2015, and also one day a week at Radboudumc. He continues to do so after his appointment. At UMC Utrecht, Lodewijk leads the Gastrointestinal and Neuroendocrine Pathology research group.
According to him, this cooperation between disciplines, various centers and abroad is essential, especially with the rare tumors he has to deal with. Doctors from different fields discuss patients and their treatment together. The questions that arise there in turn form the starting point for new research.
Lodewijk joins forces with pathologists, surgeons, endocrinologists, oncologists, molecular biologists, epidemiologists and health economists, among others.
Lodewijk works within, for example, the Expertise Center for Endocrine Tumors, a collaboration between UMC Utrecht and the NKI/AVL (Netherlands Cancer Institute/Antoni van Leeuwenhoek Hospital).
In the region, Lodewijk works closely with colleagues from various disciplines within the RAKU (Regional Academic Cancer Center Utrecht), which is a part of Oncomid (Oncology Central Netherlands).
He also participates in various national research networks. For example, there is the expertise group of the Dutch Society for Pathology. And nationally, there are the DPCG (Dutch Pancreatic Cancer Group) and the DBNETS, the Belgian-Dutch collaboration of NET excellence centres. The latter two are particularly important for national collaborations and knowledge exchange about research.
Lodewijk was also very active internationally. In addition to the European NET society, among others, he maintains very close ties with his own worldwide network of NET and pancreatic pathologists and researchers. He consults with some of them monthly, not only about research but also sometimes about difficult patient cases.
“Because pathology is very digitized, you can easily and easily discuss a difficult case with other experts in the Netherlands or abroad. I have short lines of communication with various experts at home and abroad, which regularly provides direct benefits for the quality of patients’ diagnostics.”
Lodewijk also involves patients directly in his research. For example, patient representatives provided input to several of his research projects on neuroendocrine tumors. In addition, patients will also be asked what they would think of reducing check-ups after surgery for a low-risk tumor.
“The multidisciplinary nature of my work constantly raises new research questions. As a result, my research remains closely linked to problems we encounter in practice.”
One of Lodewijk’s research projects at the moment concerns the number of necessary check-ups in people who have undergone surgery for a neuroendocrine tumor in the pancreas, a so-called pNET. Standard policy is that people have to come for an annual check-up for 10 to 20 years after a pNET has been removed, while in most patients the tumor never returns. This causes fear, stress and discomfort for the patient every year.
Lodewijk and his team are now investigating which genetic traits help in recognizing benign pNETs. And they are looking at whether these characteristics are also related to the absence of metastases. Based on this, they make a model to predict the chance of the tumor returning. As a result, fewer checks may be needed in the future.
“With this, we want to reduce unnecessary and lengthy checks. My goal is that these biomarkers are taken into account as standard in the choice of the right treatment or the degree of post-operative checks that are needed.”
This saves a lot of discomfort for the patient. And at the same time, it is good for healthcare as a whole, because extra costs due to scans and hospital visits may be saved.
With his chair, Lodewijk emphatically brings together care, research and education. In the research, he supervises PhD students and students of medicine and biomedical sciences. In addition, he teaches students, pathologists in training and other medical specialists. In this way, he not only develops new knowledge, but also transfers it to the next generation of researchers and doctors.
The social significance of his chair lies mainly in translating increasingly extensive knowledge about cancer into better choices for patients. In this way, the research contributes to more person-centred and effective care.
In the coming years, Lodewijk wants to further combine molecular profiles with existing diagnostics, among other things. He also sees opportunities for AI within pathology. For example, AI can help pathologists recognize tumors more quickly based on large amounts of data entered from (former) patients more quickly. This is already happening at UMC Utrecht, for example, when detecting metastases in breast cancer.
“There is also more and more work for pathologists, also because we are dealing with an aging population. As a result, the demand for care is increasing because there are more older patients. But at the same time, many pathologists are also retiring,” says Lodewijk.
“I hope AI can help by making some of our routine work more efficient and faster. This will be necessary to get all the work done in the future and to keep healthcare costs manageable. My ambition is that new developments in pathology and molecular oncology will lead directly to better patient care,” says Lodewijk.
