Every October, Breast Cancer Awareness Month brings people around the world together under the pink ribbon to raise awareness, encourage early detection, support patients and fund research.
To mark this year's campaign, COST is publishing a success story about the LOBSTERPOT Action on lobular breast cancer. The aim of this research initiative is to improve the detection, treatment and outcomes for patients.
The cancer that hides
For years, invasive lobular cancer (ILC) was one of the least understood forms of breast cancer. Despite being the second most common type, research efforts were scattered and coordinated clinical approaches were limited.
To change this, the COST Action Lobular Breast Cancer: Discovery Science, Translational Goals, Clinical Impact (LOBSTERPOT) brought together researchers, clinicians, and patient advocates, establishing one of the world's leading scientific communities dedicated to this disease. In the process, the network has launched new clinical trials, developed diagnostic guidance that could influence future global standards, and transformed the way ILC is studied and understood.
"ILC represents 15% of all breast cancers; it is thereby the second most common breast cancer type", explains Prof. Patrick Derksen, Chair of the Action from the University Medical Center Utrecht in the Netherlands.
Unlike many tumors that appear clearly on scans, ILC often does not form a palpable lump and can spread quietly through tissue, making it difficult to detect and monitor. Even when the disease becomes metastatic, imaging remains challenging because of its diffuse growth pattern.
"ILC is caused by a specific genomic defect leading to loss of cell-to-cell adhesion," says the Chair. "Due to this adhesive loss, ILC grows as single cells, does not form a mass and is often missed during standard mammography analysis."
The disease is also treacherous. Patients often respond well to initial hormone therapy, creating an early sense of optimism. However, years later, the cancer can return.
"ILC is renowned for its long latency metastatic relapses, which currently cannot be cured," explains Prof. Derksen.
Standard chemotherapy is also less effective for many patients, resulting in poorer long-term outcomes more than a decade after diagnosis.
Turning fragmentation into collaboration
The need for a coordinated response became increasingly clear.
"When we started the European Lobular Breast Cancer Consortium in 2018, a centralisation of biomedical and clinical efforts was lacking," Patrick Derksen recalls.
Researchers, pathologists, oncologists, surgeons, bioinformaticians and epidemiologists joined forces with patient advocates to build what would become the world's leading ILC network.
Launched in 2020, the COST Action LOBSTERPOT helped to transform these initial collaborations into a structured international platform, linking experts from Europe, the United States, and Australia.
"Our broad setup and complementarity provide an unprecedented focus and critical mass to boost biomedical knowledge and clinical intervention," says Prof. Derksen.
Through annual symposia, working groups and collaborative projects, the network created something the field had long been missing: a common space where laboratory discoveries, clinical expertise and patient perspectives could genuinely interact.
From the laboratory to the clinic
The scientific achievements of the LOBSTERPOT project quickly began to reshape the field.
One of the most influential contributions of the Action was a white paper on the pathological diagnosis of ILC, which established clearer and more uniform diagnostic criteria. This publication is expected to inform future WHO pathology guidelines, helping doctors diagnose the disease more accurately and make better-informed treatment decisions.
At the same time, the network strengthened the scientific foundations of ILC research itself. Researchers mapped the landscape of existing ILC models, creating an important reference for laboratories worldwide. They also developed around ten new tumor organoid models of metastatic ILC. These miniature, three-dimensional tumors, which are grown from patient tissue, enable scientists to study the behaviour of the disease and test potential treatments in a laboratory setting. Furthermore, the Action laid the biochemical foundation for repurposing existing drugs for ILC.
Meanwhile, discoveries were increasingly moving beyond research papers and into clinical studies. This has contributed to several ongoing ILC-specific clinical trials in Belgium, Italy, Germany, the United Kingdom, and the United States. One of these is the ROSALINE trial at the Institut Jules Bordet in Brussels. This trial is investigating a targeted medicine called Entrectinib in patients with early-stage ILC. This treatment is designed to block signals that help cancer cells to survive, providing a more precise approach than standard chemotherapy.
Another pioneering initiative has emerged at KU Leuven, where researchers have launched a rapid autopsy program focusing on metastatic ILC. By collecting tumor samples post-mortem, the Action is helping scientists better understand how the disease evolves and spreads.
These rare samples are now being shared with international partners, including the Utrecht University Medical Centre, école Polytechnique Fédérale de Lausanne and the Institute of Cancer Research in London, supporting the development of new experimental models and future therapeutic approaches.
Clinical trials designed specifically for ILC remain rare but represent an important step towards more personalized treatment strategies.
Patients as partners in research
Scientific progress within LOBSTERPOT was driven not only by laboratories and clinics, but also by the active involvement of patients and their organizations.
"The patients and their advocates have been essential to the maturation of our network," says Patrick Derksen.
Patients participated directly in the Action working groups and decision-making discussions, helping researchers better understand their experiences.
Their involvement also shaped the LOBSTERPOT's outreach activities. Together with researchers, patient advocates developed accessible information leaflets and awareness materials in fourteen languages, which are now inspiring similar initiatives within other international ILC organizations.
The collaboration has also inspired the creation of dedicated advocacy organizations, including Lobular Breast Cancer UK and Stichting Lobulair Borstkanker in the Netherlands.
"In short, patient advocates are an integral and crucial part of our organization," says Prof. Derksen.
The partnership between scientists and advocates also revealed that ILC patients were underrepresented in clinical trials investigating new targeted therapies. By documenting this issue, the COST Action LOBSTERPOT encouraged clinical investigators and pharmaceutical companies to increase efforts to include more patients with ILC in future trials.
The next chapter
For the Action Chair, one of the most memorable moments was realizng how far the network had come.
"The broad realization that the Action is an overwhelming success was deeply motivating and heartwarming for me, my co-Chair Dr. Christine Desmedt, and all the colleagues involved in the setup of our research consortium," he says.
As the network expanded, the LOBSTERPOT's annual symposia evolved into major international gatherings and an important hub for a scientific community from around the world.
"The International Symposia we organized in Utrecht and Leuven were major successes," Prof. Derksen recalls. "They attracted large crowds comprised of world-leading scientists and medical experts, complemented by a strong attendance of patient advocates and their organizations."
But despite the progress, many of the biggest scientific questions surrounding ILC remain unanswered. Researchers are now focusing on why relapses can occur many years after treatment, how imaging technologies can be improved and how more effective targeted therapies can be developed.
The Action network is now working hard on improving training programs, including initiatives focused on tumor dormancy, the immune system and future clinical interventions, and aims to submit an improved MSCA-DN application in 2027.
"Our ultimate goal," concludes Patrick Derksen, "is to keep improving the understanding of the biology of ILC, and translate this knowledge to better diagnosis and treatment of women suffering from invasive lobular breast cancer."
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