In a video published on his Instagram account, Dr Olivier Marpeau aka @mon.gyneco, in commercial collaboration with the Institut Curie, returns with researcher Fatima Mechta-Grigoriou to triple negative breast cancer. The answer is clear: these tumors lack classic therapeutic targets, and research is now trying to better understand resistance.
What makes these cancers more difficult to treat
Breast cancer is said to be triple negative when the tumor has no estrogen receptors, no progesterone receptors, and no overexpression or amplification of HER2. In other words, the absence of the three classic targets limits the use of hormonal therapies and anti-HER2 treatments.
“Triple negative tumors, as the name suggests, are negative for hormone and HER2 receptors.”
This point, recalled in the video, partly explains why this form of breast cancer is often considered more complex. According to the National Cancer Institute, this subtype tends to grow faster, recur more often than other invasive breast cancers, and is more commonly diagnosed in younger women. However, this does not make it possible to predict the evolution of a given patient: the prognosis depends in particular on the stage, the general condition and the response to treatment.
Therapeutically, chemotherapy remains a major pillar. Experts also emphasize the contribution of immunotherapy, but this idea must be formulated with caution: immunotherapy does not automatically concern all patients. In France, pembrolizumab can be used, in certain indications, with chemotherapy before surgery and then continued after surgery in adults with locally advanced, inflammatory or early-stage triple-negative breast cancer at high risk of recurrence.
To go further on the basics of this disease, you can consult our article to understand triple negative breast cancer, as well as our analysis of the benefit of immunotherapy in triple negative breast cancer.
Resistance: what research is exploring today
In the video, experts point out that around 40% of patients are still resistant to treatments combining chemotherapy and immunotherapy. This figure reflects a real problem, but it must be read with nuance: according to studies, we do not always measure the same thing. This may include a lack of complete response to surgery, recurrence, or metastatic progression. A significant proportion of patients do not respond completely or relapsebut the exact percentage depends on the criterion used.
The central message therefore remains the following: despite progress, certain tumors still escape treatment. Researcher Fatima Mechta-Grigoriou emphasizes that this resistance sometimes arises “for reasons that are currently unknown.”. This is precisely what the RHU CASSIOPEIA program, coordinated by the Institut Curie, aims to shed light on.
This research program, presented in the video and described by the National Research Agency, explores several complementary axes:
- Better predict metastases and recurrences, with a diagnostic challenge;
- Study the molecular characteristics of tumors at diagnosis, during treatment and after treatment, in order to identify useful biomarkers;
- Better understand the role of cancer-associated fibroblasts, cells in the tumor environment that could participate in resistance.
These avenues are important, because they shift the question: it is not only a question of attacking the cancer cell, but also of understanding its environment and its evolution under treatment. CASSIOPEIA seeks to identify what, from diagnosis or during treatment, could signal a risk of poor response.
But any shortcut must be avoided: this work is research and does not correspond to routinely available treatments. They also do not allow, at this stage, to tell a patient whether or not she will respond to a given treatment. The therapeutic strategy remains decided by the oncology team based on the stage, tumor profile, treatments already received and the clinical situation.