Breast Cancer: About Breast Cancer

Like cancer in other parts of the body, breast cancer involves the growth and multiplication of abnormal cells.

When the normal process of cell growth is disrupted, new cells begin to form when the body doesn’t need them and old or damaged cells fail to die when they should. These abnormal cells often form a mass of tissue called a lump or tumor. These growths can be benign (not dangerous to a patient’s health) or malignant (in need of immediate treatment).

When malignant cells form in the tissues of the breast, they can invade the surrounding tissue or spread to other areas of the body. With early detection and treatment, however, most breast cancer patients continue to lead a normal life.

Breast cancers may be either hormone receptor-positive or hormone receptor-negative, meaning that some tumors are fuelled by the body’s production of estrogen or progesterone (hormone sensitive), while others do not.

Source: Columbia’s Clinical Breast Cancer Program:

The breast is mostly made up of fatty tissue. Within this tissue is a network of lobes, which are made up of tiny, tube-like structures called lobules that contain milk glands. Tiny ducts connecting the glands, lobules, and lobes, carry the milk to the nipple.

Blood and lymph vessels also run throughout the breast; blood nourishes the cells, and the lymph system drains bodily waste products. The lymph vessels connect to lymph nodes, the tiny, bean-shaped organs that help fight infection.

Most commonly, breast cancer begins in the ducts that carry milk to the nipple (called ductal carcinomas). About 80 percent of all breast cancers originate here.

Less commonly, lobular carcinomas are those that develop in the cells lining the lobules that produce milk. When a ductal or lobular carcinoma does not spread beyond the original duct or lobule, it is termed in situ; cancers that spread to other tissues are called invasive cancers.

More uncommon are breast sarcomas, which originate in the bone, muscle, fat, or connective tissue.
Other, less common, types of breast cancer include medullary, mucinous, tubular, metaplastic and papillary breast cancer.

Inflammatory breast cancer is a faster-growing type of cancer accounting for about 1% to 5% of all breast cancers.