What are the stages of Breast Cancer?
Breast cancer is staged to determine the extent of the disease and guide treatment decisions. The stages of breast cancer are categorized based on the size of the tumor, its involvement in nearby lymph nodes, and whether it has spread to other parts of the body.
The most commonly used staging system is the TNM system, which stands for Tumor, Node, and Metastasis.
Metastasis is when cancer spreads from its original site to other parts of the body. Cancer cells break away from the primary tumor and travel through the bloodstream or lymphatic system, forming new tumors in distant organs or tissues. Metastasis makes cancer treatment more challenging and can affect the prognosis.
Here are the general stages of breast cancer:
Stage 0. This stage is known as carcinoma in situ, where abnormal cells are confined to the ducts (ductal carcinoma in situ, DCIS) or lobules (lobular carcinoma in situ, LCIS) and have not invaded surrounding tissue. Stage 0 breast cancer is considered non-invasive.
Stage I. At this stage, the tumor is small and confined to the breast. It has not spread to the lymph nodes or other parts of the body. Stage I is divided into IA and IB based on the size of the tumor.
Stage II. In stage II, the tumor is larger than in stage I or may have spread to nearby lymph nodes, but it has not spread to distant sites. Stage II is also divided into IIA and IIB based on the tumor size and lymph node involvement.
Stage III. This stage is further divided into IIIA, IIIB, and IIIC, depending on factors such as tumor size, lymph node involvement, and presence of cancer in the chest wall or skin. In stage III, the cancer may have spread extensively to the lymph nodes but is still localized to the breast and nearby areas.
Stage IV. Stage IV breast cancer, also called metastatic or advanced breast cancer, indicates that cancer has spread to distant organs such as the lungs, liver, bones, or brain. At this stage, the cancer is considered to be in an advanced state and requires systemic treatment.
