Unlocking New Hope for Small Bowel Adenocarcinoma
A rare cancer that deserves more answers: progress from a Small Bowel Adenocarcinoma project
By Julia Bromann, MD, PhD-student and Dan Høgdall, MD, PhD, Principal Investigator,
Department of Oncology, Copenhagen University Hospital – Herlev
Small bowel adenocarcinoma (SBA) is one of the rarest cancers of the digestive system. Each year, only around 70 to 80 patients are diagnosed in Denmark, and around 3,600 across Europe, but the number of new patients is reported to be growing. Because so few patients are diagnosed annually, SBA has received far less research attention than more common digestive cancers such as colorectal or pancreatic cancer. The result is that treatment options remain limited and survival rates are poor when the disease has advanced.
For patients facing this diagnosis, the scarcity of evidence translates directly into fewer choices, less certainty, and limited access to the targeted therapies that have transformed outcomes in other cancer types. Closing that gap is the purpose of our research project.
What the project aims to do
The project, titled “Molecularly redefining small bowel adenocarcinoma to accelerate precision patient care,” is funded by the Aage og Johanne Louis-Hansens Fond and Eva og Henry Frænkels Mindefond and supported by Digestive Cancers Europe (DiCE) and Danish patient associations. The central hypothesis is that SBA is not one disease but several, and that some subtypes share important biological features with other digestive cancers such as colorectal cancer, gastric cancer, biliary tract cancer (BTC), or pancreatic cancer. If that is true, treatments that already work in those cancers may benefit SBA patients as well.
Precision oncology for digestive cancers is not a theoretical concept: it is already changing lives. In colorectal cancer, identifying mutations in a gene controlling cell division (BRAF) or a defect in a cellular repair system called mismatch repair (dMMR) now guides treatment decisions and has meaningfully improved outcomes for specific patient groups. In biliary tract cancer, targeted therapies directed at specific molecular changes have become standard of care. In pancreatic cancer, new drugs targeting the KRAS gene are emerging with real promise. Our hypothesis is that similar biological vulnerabilities exist within SBA, and that systematically mapping them will open similar opportunities for patients.
Importantly, our group has recently published data suggesting that a substantial proportion of SBA tumours carry dMMR, the same defect that predicts benefit from immunotherapy in colorectal cancer. This is a clinically significant finding, since it means that a group of SBA patients may already have access to an effective treatment strategy, provided we identify them. It also points to a clear and immediate clinical implication: all patients diagnosed with SBA should be tested for dMMR as part of their routine workup.
Where we stand today
We have now built a clinical database of 326 patients with SBA from hospitals across Denmark, substantially exceeding our initial target of 200 patients. Forty-two newly diagnosed patients have been enrolled prospectively, meaning they have agreed to share their tumour tissue and clinical data with the project on an ongoing basis.
This summer, the molecular profiling phase is planned to begin. Tumour tissue from our cohort will be analysed in detail to map the genetic landscape of SBA in Denmark. The aim is not only to characterise the disease, but to build a well-defined cohort that can serve as a comparison population for future clinical trials. This is essential infrastructure, since rare cancers often lack the control data that trial designers need, and establishing it now will accelerate the development of new therapeutic strategies for this patient group.
MD and PhD student Julia Bromann joined the project in February 2026 and is now focused on the scientific work. Results have already been presented at national and Nordic conferences, and an abstract has been submitted to ESMO, the leading European oncology congress.
We are deeply grateful to all the patients who have contributed their data and tissue to this project. Their willingness to participate is what makes this research possible. We are equally grateful for the partnership of DiCE and our patient associations, whose support ensures that rare cancer patients remain at the centre of this work.
Authors:
