What is breast cancer?
Breast cancer is a malignant tumor that starts in the cells of the breast. A malignant tumor is a group of cancer cells that can grow into (invade) tissues or spread (metastasize) to distant areas of the body around. The disease occurs almost exclusively in women, but men can do it, too.
The normal breast
To understand breast cancer, it helps to have some basic knowledge about the normal structure of the breasts, as shown in the following diagram.
The female breast is composed mainly of lobules (milk-producing glands), ducts (small tubes that carry milk from the lobules to the nipple), and stroma (fatty tissue and connective tissue surrounding the ducts and lobules, vessels blood and lymph vessels).
Most breast cancers begin in cells that line the ducts (ductal cancer). Some start in the cells that line the lobules (lobular cancer), while a small number start in other tissues.
The (lymph) lymphatic system of the breast
The lymphatic system is important to understand because it is a form of breast cancer can spread. This system has several parts.
Lymph nodes are small groups of immune system cells (cells that are important in fighting infections) that are connected by lymphatic vessels, bean-shaped. Lymphatic vessels are like small veins, except that they carry a clear fluid called lymph (instead of blood) away from the breast. Lymph contains tissue fluid and waste products, as well as immune cells. The breast cancer cells can enter lymphatic vessels and begin to grow in lymph nodes.
Most lymphatic vessels in the breast connect to lymph nodes under the arm (axillary nodes). Some lymphatic vessels connect to lymph nodes inside the chest (internal mammary nodes) and either above or below the collarbone (supraclavicular or infraclavicular nodes).
If cancer cells have spread to lymph nodes, there is a greater likelihood that the cells could have also entered the bloodstream and spread (metastasize) to other parts of the body. The more lymph nodes in breast cancer cells, it is likely that cancer can be found in other organs as well. Because of this, the search for cancer in one or more lymph nodes often affects the treatment plan. However, not all women with cancer cells in their lymph nodes develop metastases, and some women may have cancer cells in the lymph nodes and later develop metastases.
Benign breast lumps
Most breast lumps are not cancerous (benign). Still, some may need a biopsy (sample and viewed under a microscope) to prove they are not cancer.
Fibrosis and cysts
Most lumps turn out to be caused by fibrosis and / or cysts, benign changes in breast tissue that occur in many women at some point in their lives. (This is sometimes called fibrocystic changes and used to be called fibrocystic disease.) Fibrosis is the formation of scar (fibrous) tissue, and cysts are fluid-filled sacs. These conditions are most often diagnosed by a doctor based on the symptoms, such as breast lumps, swelling and tenderness or pain. These symptoms are often worse just before the menstrual period of women is about to begin. Your breasts may feel lumpy and, sometimes, you may notice a discharge from clear or slightly cloudy nipple.
Intraductal papillomas and fibroadenomas
Benign breast tumors such as fibroadenomas or intraductal papillomas are abnormal growths, but they are not cancerous and do not spread outside the breast to other organs. They are not life threatening.
But some benign breast conditions are important because women with these conditions have an increased risk of developing breast cancer.
Breast cancer is a malignant tumor that starts in the cells of the breast. A malignant tumor is a group of cancer cells that can grow into (invade) tissues or spread (metastasize) to distant areas of the body around. The disease occurs almost exclusively in women, but men can do it, too.
The normal breast
To understand breast cancer, it helps to have some basic knowledge about the normal structure of the breasts, as shown in the following diagram.
The female breast is composed mainly of lobules (milk-producing glands), ducts (small tubes that carry milk from the lobules to the nipple), and stroma (fatty tissue and connective tissue surrounding the ducts and lobules, vessels blood and lymph vessels).
Most breast cancers begin in cells that line the ducts (ductal cancer). Some start in the cells that line the lobules (lobular cancer), while a small number start in other tissues.
The (lymph) lymphatic system of the breast
The lymphatic system is important to understand because it is a form of breast cancer can spread. This system has several parts.
Lymph nodes are small groups of immune system cells (cells that are important in fighting infections) that are connected by lymphatic vessels, bean-shaped. Lymphatic vessels are like small veins, except that they carry a clear fluid called lymph (instead of blood) away from the breast. Lymph contains tissue fluid and waste products, as well as immune cells. The breast cancer cells can enter lymphatic vessels and begin to grow in lymph nodes.
Most lymphatic vessels in the breast connect to lymph nodes under the arm (axillary nodes). Some lymphatic vessels connect to lymph nodes inside the chest (internal mammary nodes) and either above or below the collarbone (supraclavicular or infraclavicular nodes).
If cancer cells have spread to lymph nodes, there is a greater likelihood that the cells could have also entered the bloodstream and spread (metastasize) to other parts of the body. The more lymph nodes in breast cancer cells, it is likely that cancer can be found in other organs as well. Because of this, the search for cancer in one or more lymph nodes often affects the treatment plan. However, not all women with cancer cells in their lymph nodes develop metastases, and some women may have cancer cells in the lymph nodes and later develop metastases.
Benign breast lumps
Most breast lumps are not cancerous (benign). Still, some may need a biopsy (sample and viewed under a microscope) to prove they are not cancer.
Fibrosis and cysts
Most lumps turn out to be caused by fibrosis and / or cysts, benign changes in breast tissue that occur in many women at some point in their lives. (This is sometimes called fibrocystic changes and used to be called fibrocystic disease.) Fibrosis is the formation of scar (fibrous) tissue, and cysts are fluid-filled sacs. These conditions are most often diagnosed by a doctor based on the symptoms, such as breast lumps, swelling and tenderness or pain. These symptoms are often worse just before the menstrual period of women is about to begin. Your breasts may feel lumpy and, sometimes, you may notice a discharge from clear or slightly cloudy nipple.
Intraductal papillomas and fibroadenomas
Benign breast tumors such as fibroadenomas or intraductal papillomas are abnormal growths, but they are not cancerous and do not spread outside the breast to other organs. They are not life threatening.
But some benign breast conditions are important because women with these conditions have an increased risk of developing breast cancer.
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