A distinction is made between invasive breast cancers or “invasive carcinomas”, pre-cancerous lesions also called “carcinomas in situ”. Medical management and prognosis vary considerably depending on the nature of the cancer, its degree of tumor aggressiveness, the histological type, and the stage of the disease.
Carcinomas in situ are by definition non-invasive, that is to say that they theoretically have no metastasizing potential (they cannot metastasize at a distance, they cannot become generalized). They are rare (less than 5 to 10% of breast tumors). Exceptionally, they can, for reasons not well known, invade the relay ganglion (called sentinel ganglion). Treatment is based on the combination of surgery, which is usually conservative (except for lesions extending to the entire breast) supplemented by adjuvant radiotherapy (i.e. done postoperatively) which aims to decrease the risk of local recurrence of the disease. The risk of local recurrence in the event of conservative surgery alone (without adjuvant radiotherapy) is 30%, while this same risk is divided by 2 when radiotherapy completes the treatment. In the event of radical treatment (total mastectomy), there is no indication for additional radiotherapy, and the risk of local recurrence is 15%, which is identical to that of conservative treatment supplemented with radiotherapy. adjuvant.
The invasive breast carcinomas are overwhelmingly divided into two cancer subtypes: ductal carcinomas (developed at the expense of the canaliculi of the breast) which represent 80% of tumors, and lobular carcinomas (developed at the expense of the lobules of the breast ) which represent 15% of tumors. The other histological types represent less than 5% of tumors. The treatment of localized forms (free from metastases) generally involves the association of surgery (radical or conservative) the aim of which is the removal of the tumor and at least of its so-called sentinel node (relay node), or even d ” axillary dissection (removal of the lymph node chain), usually supplemented by radiotherapy on the breast, or even on neighboring lymph node areas (supraclavicular, axillary area, and internal mammary chain) in order to reduce the risk of recurrence locoregional disease.
The therapeutic strategy is defined in a Multidisciplinary Consultation Meeting (RCP) where all cancer treatment specialists (senologist surgeons, gynecologists, radiotherapists, chemotherapists, anatomo-pathologists, radiologists, nuclear physicians, etc.) are present to propose to the patient personalized treatment best suited to the characteristics of his tumor. In certain situations, when the tumor is aggressive, large or when neighboring lymph nodes are invaded by the disease, chemotherapy is undertaken to reduce the risk of metastatic spread of the disease (risk of the disease spreading). Chemotherapy can be administered to the patient before surgery (this is called neoadjuvant treatment) to reduce the size of the tumor and facilitate the preservation of the breast, or when the risk of metastatic spread is high. Most often, chemotherapy, when it is chosen, is given after surgery and before radiotherapy. Certain tumors expressing specific receptors, such as Her2, make the tumor sensitive to targeted therapies which are then delivered to patients in addition to chemotherapy. 85% of breast cancers are said to be hormone-dependent or sensitive, which means that there are receptors for female sex hormones such as estrogen and progesterone on the surface of tumor cells. In this situation, the patient will be prescribed, at the end of the therapeutic sequence, “hormone therapy” the aim of which is to bind to these receptors and inhibit the proliferation of any residual tumor cells.
The therapeutic strategy for the management of breast cancer is based on multidisciplinary expertise and is constantly evolving, in line with new data from the scientific community.
