What is the difference between invasive and non-invasive breast cancer?

Invasive breast cancer – the cancer cells break out from inside the lobules or ducts and invade nearby tissue. With this type of cancer, the abnormal cells can reach the lymph nodes, and eventually make their way to other organs (metastasis), such as the bones, liver or lungs. The abnormal (cancer) cells can travel through the bloodstream or the lymphatic system to other parts of the body; either early on in the disease, or later.

Non-invasive breast cancer – this is when the cancer is still inside its place of origin and has not broken out. Lobular carcinoma in situ is when the cancer is still inside the lobules, while ductal carcinoma in situ is when they are still inside the milk ducts. “In situ” means “in its original place”. Sometimes, this type of breast cancer is called “pre-cancerous”; this means that although the abnormal cells have not spread outside their place of origin, they can eventually develop into invasive breast cancer.