Because these cells have not broken through the membrane and they are confined, they do not have the potential to spread. Invasive Cancers Invasive cancer refers to those ductal or lobular cancers that have broken through the membrane around the ducts or lobules. Invasive cancer does not necessarily mean the cancer has metastasized or spread to other parts of the body. The type, size and spread of cancer is important information to help a doctor determine a course of treatment. Whatever the stage of the tumor at the time of diagnosis there are aggressive, effective therapies available.
Cancer is only in the breast.
Stages of Breast Cancer Breast Cancer stages are based on the type, size and spread of cancer. Stage 0 involves only a small cluster of cancer cells in the duct or lobule. Stage 1 is a tumor smaller than 2 cm. Stage 2 is a tumor up to 5 cm that has not spread to the axillary lymph nodes. Stage 3 is a tumor of any size that may have spread to the axillary lymph nodes.