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Breast cancer

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What is breast cancer?
Breast cancer is the most common cancer in women - it accounts for 33% of new cancer cases every year. It affects more than 60,000 women a year in France, but its survival rate is 87% at the five-year mark. It should be noted that less than 1% of breast cancers occur in men.
Cancer cells may be contained within the lobules (the group of glands that produce milk) or ducts of the breast (which carry milk), or they may invade nearby tissues, such as lymph nodes under the armpit. In the first case, we are talking about carcinoma in situ and in the second - of invasive carcinoma. Cancer cells can then pass into the blood and cause metastases.
The tumors at the origin of breast cancers are classified into four categories, which determine future treatment:
- Luminal cancer accounts for 70 to 80% of cases. Cancer cells have hormone receptors, and therefore hormones (estrogens and progesterone) play a role in the proliferation of cells. There is a "luminal A" type that has more estrogen receptors and a "luminal B" type that has slightly fewer of them.
- HER2+ breast cancer: In this case, the cancer cells overexpress the HER2 growth factor receptor on their surface. However, when activated, this receptor causes a significant proliferation of cells.
- Triple-negative breast cancer: Cancer cells do not express either estrogen or progesterone receptors and do not overexpress the HER2 receptor. It is considered more aggressive.
- Basal-like cancer is also often triple-negative, but the cancer cells express other modified proteins. It is therefore considered a separate type of cancer as well.
Metastatic breast cancers
15 to 20% of breast cancer patients will develop a metastatic form, that is to say that cancer cells, originating in the breast, will form tumors in other organs (often bones, lungs, liver, skin, or brain). These metastases can be present from the moment of diagnosis or appear later, in particular during a recurrence. They will have the same molecular characteristics as the original tumor and will require appropriate treatment.
Other breast cancers
There are rare or very rare forms of the disease: medullary, papillary, tubular or mucinous cancers, which generally have a good prognosis. Breast cancer can also be "inflammatory", especially in young women: the cancer cells cause inflammatory symptoms (red and hot breast, local and sudden pain, "orange peel" appearance) by blocking the lymphatic ducts under the skin of the breast. This is considered more aggressive than classic carcinomas.
Institut Curie, a referral center for the treatment of breast cancer
With more than 7,000 patients admitted each year, Institut Curie is the leading European center for breast cancer treatment.
The Institute of Women's Cancers
By placing women at the heart of research and innovation, the Institute of Women's Cancers is committed to lastingly reducing the incidence and mortality of these cancers, while fundamentally transforming the patient experience.
Co-founded by Institut Curie, PSL University, and Inserm, the Institute of Women's Cancers is a University Hospital Institute (IHU) and a recipient of the France 2030 excellence label.
The Institute was founded on a core conviction: that preventing, treating, and supporting patients with these cancers requires moving beyond a tumor-centered approach.
What sets it apart is a holistic, highly personalized model at the cutting edge of adaptive medicine — one that accounts for women's biological, clinical, psychological, and social trajectories throughout their disease and beyond.
Physicians, healthcare professionals, researchers, data scientists, and experts in humanities and social sciences — working hand in hand with patients themselves — are bringing their expertise together to address breast and gynecological cancers across the full continuum of care: prevention, diagnosis, treatment, follow-up, and long-term quality of life.
More information about the Institute of Women's Cancers
Institut Curie, the leading cancer center in France
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