Breast cancer is generally broken up into five major stages, ranging from stage 0 to stage IV. This method of tracking breast cancer progression functions as a simplified way of categorizing and organizing the disease. The classification gives medical professionals and breast cancer patients a means of understanding the characteristics that breast cancer typically displays at each stage. For each stage, cancer is grouped by tumor size and how far the cancer has spread within the body.
The first stage in breast cancer progression is stage 0, or carcinoma in-situ, and occurs when abnormal cells grow within the milk duct or lobule of the breast. At this stage, the cancer is noninvasive and has not spread to the lymph nodes. Generally, this early stage of cancer cannot be detected through a breast exam and is more likely to be found when receiving a mammogram. If treatment or detection is delayed, the cancer can advance through the walls of the duct.
Although stage 0 may be considered cancer, it is often used to describe a precancerous condition; stage I is often considered the first actual cancer stage. Together, stages I to IV of breast cancer progression all refer to invasive forms of cancer. In other words, the cancer cells have the ability to invade into surrounding normal tissue.
Both stage I and stage II breast cancers are still confined to the breast tissue. A stage I, cancer prognosis generally describes the formation of a small tumor measuring less than 1 inch (around 2 centimeters). By the time of a stage II breast cancer progression, however, the tumor is beginning to spread into a few of the axillary, or underarm, lymph nodes.
Phase II breast cancer is further broken down into two subclasses, stage IIA and stage IIB. Generally, stage IIA refers to a cancerous growth smaller than 1 inch (around 2 centimeters) that is also affecting the lymph nodes. It may also refer to a tumor of up to 2 inches (around 5 centimeters) which has not yet spread into the lymph nodes. Stage IIB, is more advanced than stage IIA and is distinguished by tumors measuring between 1 to 2 inches (roughly 2 to 5 centimeters) that have begun dispersing into the underarm lymph nodes. The stage IIB diagnosis can also apply to tumors that are greater than this size but have not yet extended down into the underarm lymph nodes.
Once breast cancer progresses to stage III or later, the cancerous tumor is advancing outside of the local area of the breast. At stage III, tumors are larger than 2 inches (about 5 centimeters) and can be further broken up as stage IIIA, stage IIIB and stage IIIC. Stage IIIA describes cancer cells that are in the lymph nodes, but a tumor is not found in the breast. Regardless of the tumor size in the breast when cancerous cells are joining in the lymph nodes, the condition is also generally described as stage IIIA. The diagnosis of stage IIIB typically indicates that a cancer has spread to the skin of the breast or other nearby tissues, while a stage IIIC cancer is spreading through the lymph nodes into the collarbone and the breastbone.
At stage IV, the breast cancer progression is considered metastatic. This indicates that the cancer is spreading through the lymphatic system or the blood into distant parts of the body. By the time cancer has reached this stage, it has the capability to spread to practically anywhere in the body. Organs commonly affected by the advanced of breast cancer include the brain, bones or lungs.
Understanding breast cancer progression can help patients better appreciate how far their condition has advanced. From a medical standpoint, this information provides a basis for deciding how aggressively to treat the disease. Although survival rates for breast cancer does go down once the cancer has spread outside of the breast, this does not mean that treatment will be unsuccessful. By combining different treatment options such as chemotherapy, radiation therapy and surgical removal of the tumor, breast cancer sufferers can improve their chances of surviving malignant breast cancer.