Breast cancer is the second most common type of cancer in women after skin cancer, according to the CDC. Cancer is staged due to its size and spread, with Stage III breast cancer considered to be an aggressive type of cancer likely to do harm, reports Net Doctor.
Stage III breast cancer is considered to be invasive, meaning that the cancerous cells are affecting surrounded tissues in the breast. This makes the cancer more dangerous as it can spread to distant areas, according to BreastCancer.org.
There are three grades of Stage III breast cancer--grades A, B and C. The grade depends on the size, lymphatic involvement and spread of the cancer, per the American Cancer Society.
For Stages IIIB or IIIC of aggressive breast cancer, the tumour has grown into the wall of your chest. In Stage IIIA, the cancer is still contained within the breast.
In order to qualify as Stage III, breast cancer cells cannot have spread to any distant sites; however, the cancer can have spread to the lymph nodes. Tumours that involve less than nine lymph nodes often are termed Stages IIIA or IIIB, with more lymph node involvement signalling classification of Stage IIIC.
Breast cancers that are less than five centimetres in width and have spread to four to nine lymph nodes are generally classified as Stage IIIA, per the American Cancer Society. If tumours have grown into the chest wall or involve more lymph nodes, Stage III classification is given to tumours of any size provided the cancer has not spread to any distant location.
According to the American Cancer Society, 57 per cent of women with Stage III breast cancer survive five years after diagnosis.