Ductal Carcinoma in Situ (DCIS), meaning “cancer in the original place”, is the presence of abnormal cells confined to the milk duct in the breast. This type of breast cancer is considered non-invasive, meaning that it hasn’t spread outside of the duct into the surrounding breast tissue. DCIS is considered the earliest form of breast cancer – Stage 0.
Once the abnormal cells begin to spread outside of the milk ducts into the surrounding breast tissue, it becomes Invasive Ductal Carcinoma. This is the most common type and accounts for 70% - 80% of all breast cancers. IDC is also the type of breast cancer usually found in men.
With Metastatic Breast Cancer – classified as Stage 4, the cancer has started spreading to other parts of the body. How does cancer spread or metastasize? According to the National Breast Cancer Foundation, Cancer spreads through one of the following ways:
- Cancer cells invade nearby healthy cells
- Cancer cells penetrate into the circulatory or lymph system
- Migration through circulation
- Cancer cells lodge in capillaries
- New small tumors grow (micro-metastases)