Stage 3 breast cancer is advanced cancer that has spread only to the lymph nodes
Stage 3 cancer is advanced cancer that has spread to the lymph nodes, but not other places in the body. There are 3 categories of stage 3 cancer. Stage 3A, 3B, and 3C are based on size and number of lymph nodes involved. Stage 3A means that cancer has spread to anywhere between 4-9 lymph nodes, or the tumor is bigger than 5 centimeters and has clusters of involved lymph nodes. A cancer is also considered 3A if the tumor is over 5 centimeters and is near the breastbone with 1-3 involved lymph nodes. At stage 3B, cancer has invaded the chest wall or skin and has spread to up to 9 lymph nodes. At 3C, there are more than 10 lymph nodes involved, or lymph nodes near the collarbone or near the breastbone are affected.