Breast cancer is a malignant tumor that can be cured in 9 out of 10 cases if diagnosed early enough. There are different types of breast cancer depending on the cells involved and their degree of aggressiveness. With new treatments and new strategies, the prognosis of severe forms is also improving.
What is breast cancer?
Breast cancer is the most common cancer in women. It accounts for more than one third of all new cases of cancer in women.
Each breast contains a mammary gland, itself composed of fifteen to twenty lobules and channels, as well as supporting tissue that contains vessels, lymphatic channels and fat. The role of the lobules is to produce milk during breastfeeding and that of the canals to transport that milk to the nipple.
The mammary gland develops and functions under the influence of sex hormones made by the ovaries. These hormones are estrogens, which allow in particular the development of the breasts at the time of puberty and throughout the pregnancy, as well as the progesterone which plays a role in the differentiation of the cells of the breast and on the menstrual cycle, by preparing for example the uterus to a possible pregnancy.
Breast cells sometimes undergo changes that make their growth pattern or behavior abnormal. These changes may result in benign breast disease, such as atypical hyperplasia or breast cysts, or, more rarely, changes in the breast cells that cause breast cancer.
Breast cancer is most commonly found in the cells lining the ducts carrying milk from the glands to the nipple: this type of breast cancer is called “ductal carcinoma”. Cancer can also form in the cells of the milk producing glands (grouped into lobules): this type of cancer is called “lobular carcinoma”.
These two cancers (ductal and lobular carcinomas) may be “in situ”, that is, they will remain confined to their original location and not invade neighboring tissues. They can also be “invasive”, or “invasive”, that is to say, they spread in neighboring tissues.
Other types of less frequent breast cancers can also be observed: inflammatory breast cancer, triple negative breast cancer, basal type breast cancer and, very rarely, sarcoma.
What are the different types of breast cancer?
• Benign tumors have well-defined contours. They have a slow growth and remain localized in the tissue or organ in which they appeared: they do not lead to metastases in other areas of the body. Benign tumors are composed of cells that resemble normal breast tissue cells. They say they are “well differentiated”.
• Malignant tumors have contours most often poorly defined. Some, however, are quite limited and can then delay the diagnosis of cancer being considered a time as benign. The cancer cells that make up malignant tumors have various abnormalities compared to normal cells: different shape and size, irregular contours … We speak of “undifferentiated cells” because they have lost their original characteristics. Malignant tumors tend to invade neighboring tissues. They can also cause metastases, that is, a new tumor in another area of the body called a “secondary tumor.” It is linked to the migration of cancer cells that escape from the primary tumor and will colonize other organs to form a metastasis.
• Most adenocarcinomas develop in the upper outer part of the breast. The most common type of malignant breast tumor is “adenocarcinoma.” There are two main types of adenocarcinoma: “ductal carcinoma” that originates in the lining of the milk ducts, or “lobular carcinoma” that originates in the milk-producing glands (lobules) of the breast.
• The ductal carcinomas and lobular carcinomas are classified as “non-invasive” (“in situ”), that is, they are confined (no spread beyond their location). origin and no invasion of surrounding tissues), or “infiltrants”, that is, they have spread beyond their original location into neighboring tissues.
What are the signs of breast cancer?
• The most common early signs of breast cancer are related to the presence of an abnormal cluster of cells in the breast.
The most common early sign of breast cancer is the discovery of a ball or mass in a breast. It is usually the woman herself who discovers this mass, but it is sometimes observed during a screening mammogram even before it can be felt by touch. The mass is constantly present, identical whatever the period of the menstrual cycle. It is usually tender, but not painful, hard, irregularly shaped, and sometimes attached to the skin or chest wall.
There may be changes in the appearance of the breast. The breast can deform and lose its shape, wrinkles can appear. The skin of the breast can become padded (and take the appearance of an “orange peel”) or wrinkled. The skin of the breast may be red, ulcerated, covered with crusts. Nipple changes may also suggest breast cancer. The nipple can point inwards (while usually it is directed outwards). A single nipple discharge may be a sign of breast cancer, especially if it occurs without nipple compression and if it contains blood or if the fluid is greenish . The formation of crusts or ulcers or peeling skin on the nipple may be a sign of a rare type of breast cancer such as nipple Paget’s disease.
Redness, swelling and significant heat in the breast may be signs of inflammatory breast cancer. Itching of a breast or nipple may be a sign of inflammatory breast cancer.
• Late signs occur when the cancerous tumor grows or spreads to other parts of the body.
The presence of small hard masses in the armpit may mean that breast cancer has spread to the axillary lymph nodes (or “axillary trough”).
The spread of cancer cells can be distant to other organs: bone pain, nausea, loss of appetite, weight loss, jaundice (yellowing of the skin and whites of the eyes with dark yellow urine), accumulation of fluid around the lungs (pleural effusion) with shortness of breath and cough, headache …
Are there breast cancers in humans?
Breast cancer starts from breast tissue and men with breast tissue like women, even if their breasts are less developed, they can also breast cancer.
• Breast cancer is rare in men: less than 1% of all breast cancers affect men.
• The risk of developing breast cancer for a man increases with age. Breast cancer is more frequently diagnosed in men over 60 years old.
• Other known risk factors are: family history of breast cancer, genetic predisposition (BRCA2), Klinefelter syndrome, radiation exposure (chest radiotherapy), or cirrhosis of the liver.
• Although the signs of cancer, the course of the disease and the management of invasive ductal carcinoma are almost identical in men and women, there are some differences. Most men with breast cancer have “infiltrating ductal carcinoma” and other types of breast cancer are very rare. Breast cancer in humans is treated like that of the postmenopausal woman, where the woman’s ovaries stop producing estrogen because they do not exist significantly in humans.
What are the factors that increase the risk of breast cancer?
There are several factors that affect the risk of developing breast cancer: we talk about risk factors, although there are still uncertainties about the degree of involvement of these factors.
It must be remembered that a person who has one or more risk factors may never develop cancer. Conversely, a person with no risk factor may have this cancer.
Apart from sex (more than 99% of breast cancers affect women), the four main risk factors for breast cancer are age, personal history (in the same breast or in the contralateral breast) and family history ( mother, sister or daughter) of breast cancer and genetic predispositions to breast cancer (BRCA1 and BRCA2 or rare genetic mutations).
Other factors that have been identified include exposure of the body to estrogen-like hormones (early menses and late menopause, prolonged hormone replacement therapy beyond 5 years), exposure to ionizing radiation (chest radiotherapy). for Hodgkin lymphoma before the age of 15), overweight, and the consumption of tobacco or alcohol.