When breast cancers have spread from their place of origin (breast ducts or lobules) into the surrounding breast tissue they are classified as invasive or infiltrating cancers. This means they have the potential to invade into blood and lymph vessels and spread (metastasise) to other sites in the body.
Learn more here: Invasive (Infiltrating) Breast Cancer - Breast Cancer Foundation
DCIS is an early form of breast cancer, sometimes called pre-cancerous, non-invasive, or intra-ductal cancer. The cancer cells are inside the milk ducts or ‘in situ’ and have not spread outside the milk duct. The milk ducts are channels in the breast that carry milk to the nipple. If DCIS is left untreated, the cells may eventually develop the ability to spread from the ducts into the surrounding breast tissue and become an invasive cancer. Not every person with DCIS will go on to develop breast cancer, but it isn’t possible to predict which DCIS will develop into breast cancer.
Learn more here: DCIS Pre-Invasive Breast Cancer - Breast Cancer Foundation
In New Zealand, around 25 men are diagnosed with breast cancer each year.
Breast cancer in men is the same disease as affects women. Although most of the available information is directed at women it is generally relevant for men too, as the diagnosis, treatment and survival rates for both sexes is very similar.
Learn more here: Breast Cancer in Men - Breast Cancer Foundation