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Representing nearly 15% of breast cancers, so-called “triple negative” cancers are very aggressive cancers against which there are few therapeutic weapons. But in this area, immunotherapy brings new hope of cure to some patients.
Breast cancer is often talked about, but the disease actually hides different forms that are more or less aggressive. Among them, triple negative breast cancer has a more difficult prognosis and a lack of therapeutic options.
Triple negative breast cancer in figures
Among the 60,000 new cases of breast cancer diagnosed each year in France, triple negative breast cancer affects approximately 15% of patients, which represents 9,000 new cases detected each year.
Not sensitive to hormonal treatments or to targeted anti-HER2 therapy, it is one of the most aggressive and difficult to treat breast cancers: three-quarters of patients do not respond to treatment. Today, treatment is mainly based on chemotherapy.
It is often diagnosed in younger women (40% are under 40 years old), with a higher risk of early metastatic recurrence and shorter overall survival compared to other breast cancer subtypes.
Immunotherapy already indicated for advanced forms of these cancers
Faced with these formidable breast cancers, immunotherapy has already shown its effectiveness for advanced cancers that cannot be operated on or that have already spread to other organs (locally recurrent unresectable or metastatic triple negative breast cancer). According to the High Authority of Health, Keytruda (pembrolizumab) in combination with chemotherapy is a first-line treatment for locally recurrent unresectable or metastatic triple negative breast cancer, whose tumors express PD-L1 with a CPS ≥ 10. The other option is based on PARP inhibitors in the case of breast cancer with a genetic predisposition (BRCA1/2 mutation).
Today, as part of the European Society of Medical Oncology 2024 congress, a study presented the interest of this same immunotherapy in patients with high-risk triple-negative breast cancer at an early stage.
A 34% reduced risk of death for early forms
In these women who can be operated on because the tumor was detected early enough, management is based on chemotherapy followed by surgery. Involving more than 1000 women, the study compared standard treatment with management that added pembrolizumab before surgery and then after surgery as monotherapy.
Results: The event-free survival rate (i.e. the proportion of women who did not experience recurrences) at 5 years was 81.2% in the immunotherapy group versus 72.2% in the standard treatment group. The overall 5-year survival in these two groups was 86.6% versus 81.7%, respectively.
“In this study, pembrolizumab combined with chemotherapy as neoadjuvant therapy and continued as monotherapy after surgery reduced the risk of death by more than a third compared with neoadjuvant chemotherapy, reinforcing the important role this regimen plays in the treatment of high-risk early-stage triple-negative breast cancer.” said Dr Peter Schmid, head of the Centre for Experimental Cancer Medicine at Barts Cancer Institute in London and lead author.
More women “cured” thanks to immunotherapy
Are these women then definitively cured? The word is handled with caution by doctors torn between the desire to reassure patients and the fear of not giving them false hope, as admitted by Professor Benoit You, oncologist at the University Hospital of Lyon: “It depends on what cure means to each patient. If it means that they have to be certain that the disease will never come back and that they can go back to their life exactly as they had before the disease, then no, we cannot say that with certainty, because even if it is low, the risk of recurrence is there. But if it means that they can go back to a normal life without thinking about the disease every day but simply monitoring their health regularly, then yes, we can tell them and with this treatment we can tell even more women.“.