Early-stage breast cancer includes stage 1, stage 2a, stage 2b and stage 3a breast cancer. In these early stages, the cancer has infected the lymph nodes that are close to the breast. The cancer has not, however, spread to other parts of the body. Health specialists will sometimes talk about noninvasive breast cancer, which refers only to stage 0 cancer. Early-stage breast cancer is considered to be invasive.
The various stages of early-stage breast cancer are determined by a number of factors. The most important of these factors are the size of the tumor and the extent to which the cancer has spread to nearby lymph nodes. The stage of cancer is determined by a specialist or physician in the early detection of breast cancer.
In stage 1 of early-stage breast cancer, the tumor has reached the size of 0.8 inches (2 cm). At this stage, the cancer has already begun invading tissue near the tumor. At this point, the lymph nodes have not yet been invaded by the cancer.
Stage 2a breast cancer occurs when the cancer has spread to nearby lymph nodes. Most often, the lymph nodes located under the arm will be infected. In some cases, this stage will be diagnosed when the lymph nodes are not infected. In this case, the tumor will have grown larger than 0.8 inches (2 cm). In order to be at stage 2a, however, the tumor cannot have exceeded 2 inches (5 cm) in size.
When the tumor is larger than 2 inches (5 cm) but has not spread to the lymph nodes, this is considered to be stage 2b breast cancer. A health specialist or physician might also diagnose a patient with stage 2b breast cancer when the cancer has invaded the axillary lymph nodes but the tumor has not yet exceeded 2 inches (5 cm).
Stage 3a breast cancer is used to describe the stage at which there may be no cancer found in the breast itself, though the cancer has spread to the axillary lymph nodes and might be creating a clump. In some cases, the axillary lymph nodes might be sticking to other structures within the body. This stage is also used to describe tumors that are at the most 2 inches (5 cm) in size. In these cases, the cancer has begun to spread to the axillary lymph nodes. This stage of early-stage breast cancer might also be diagnosed when the tumor has exceeded 2 inches (5 cm), though in these cases, the cancer has not yet spread to the lymph nodes around the breast bone.