Common Types of Breast Cancer

Breast cancer normally originates in the ducts or lobules of the breast. If the cancer cells spread outside the ducts or lobules of the breast into the surrounding tissue, this is called invasive (infiltrating) breast cancer.

The two major types of breast cancer are:

• In situ breast cancer / Pre-Invasive Breast Cancer

- This refers to a type of cancer in which the cancer cells remain confined to site of origin and have not invaded surrounding breast tissue around the duct or lobule. There are two types of in situ breast cancer, depending on site of origin:

+ Ductal carcinoma in situ (DCIS) results as a result of abnormal cells in the lining of a milk duct that have not invaded the surrounding breast tissue. Because this is an early stage, when left untreated it may eventually develop into invasive breast cancer.

+ Lobular carcinoma in situ (LCIS) involves abnormal cells contained within a lobule of the breast, without invading surrounding tissue. With LCIS, there is an increased risk of developing breast cancer in either breast in the future.

• Invasive breast cancer

- This includes breast cancers that begun to invade surrounding tissues that support the ducts and lobules of the breast. The cancer cells are able to travel to other parts of the body. There are generally two types of invasive breast cancer:

+ Invasive ductal carcinoma (IDC) accounts for the majority of invasive breast cancers. Here, cancer cells form in the lining of the milk duct and eventually break free of the ductal wall to invade surrounding breast tissue. Cancer cells may remain near the origin or spread throughout the body via blood vessels or the lymphatic system.

+ Invasive lobular carcinoma (ILC) is less common than IDC but acts in a similar manner. ILC begins in the milk-producing lobule and then spreads to the surrounding breast tissue and, furthermore, any part of the body. Sometimes a lump is not detected instead you may feel a thickening or you may sense that your breast tissue feels different. Unfortunately, as it is hard to detect by touch, one could understand the likelihood of it being detected using a mammogram.