You may know people who have had breast cancer. You may have had breast cancer yourself. No matter what your connection has been with the disease, there are always new things to learn about breast cancer and its treatment. More news is good news with this serious disease, as more advances in treatments are being researched each year. In this chapter, we give you an outline of breast cancer and its treatment. We describe breast anatomy. We discuss the various types and stages of breast cancer. We present some of the testing that is done on breast tumors to help determine prognosis and optimal therapy. We describe the various treatments for breast cancer in common practice. Finally, we present some of the new, promising research on breast cancer treatment being conducted at our institutions and around the world.

Breast Anatomy and Breast Cancer
The main components of a female breast are the lobules, or sacs, that produce milk; the ducts that connect the lobules to the nipple; and the surrounding fatty tissue. Breast cancer arises in cells lining the insides of the lobules and the ducts. The fatty tissue of the breast contains ligaments, blood vessels, and lymphatic vessels. Lymphatic vessels carry lymph, a clear fluid that contains tissue waste products and immune system cells. Cancer cells from the breast may enter lymph vessels and spread to the underarm lymph nodes, which are small bean shaped collections of immune system cells. If breast cancer cells reach the lymph nodes under the arm, they are more likely to have spread to to other organs of the body as well.

Types of Breast Cancer
Carcinoma in Situ of the Breast
In situ breast cancer is a tumor that is confined to the ducts or lobules of the breast and has not invaded surrounding fatty tissues or spread to other organs of the body. There are two types of in situ breast tumors: lobular carcinoma in situ and ductal carcinoma in situ. Lobular carcinoma in situ, commonly called LCIS, begins in the lobules but does not penetrate through the lobule walls. Most breast specialists do not consider lobular carcinoma in situ to be a true breast cancer, but women with this diagnosis have a higher risk of later developing a more serious form of breast cancer in either breast. Ductal carcinoma in situ, commonly called DCIS, is the more common type of in situ breast cancer. Ductal in situ cancer cells inside do not spread through the walls of the duct into the fatty tissues of the breast or elsewhere in the body. Ductal carcinoma in situ is most commonly diagnosed by finding abnormal calcium deposits, called calcifications, on a mammogram. The calcifications themselves do not represent cancer but signify increased breast cell activity.

Invasive Ductal Breast Cancer
Invasive ductal cancer is the most common form of breast cancer; it accounts for about 80 percent of all breast cancer cases. Some doctors call this type of cancer “infiltrating ductal cancer.” This cancer breaks through the wall of the duct to invade into the breast fatty tissue. It can spread to other parts of the body through the lymphatic system and the bloodstream.

Invasive Lobular Breast Cancer
Invasive, or “infiltrating,” lobular cancer starts in the lobules of the breast. Like invasive ductal breast cancer, it can spread beyond the breast to other parts of the body. Invasive lobular carcinoma tends to grow in a diffuse, spreading pattern within the fatty tissue of the breast instead of the solid ball pattern that is typical of invasive ductal carcinoma. Therefore, it is frequently more difficult to detect invasive lobular carcinoma with mammography or physical examination at an early stage. Invasive lobular carcinoma is also more likely to occur in both breasts.

Inflammatory Breast Cancer
Inflammatory breast cancer is an uncommon, rapidly growing, aggressive cancer. The skin of the affected breast is red, warm, and thickened with the consistency of an orange peel. These skin changes are due to the spread of cancer cells within the lymphatic channels of the skin.

Stages of Breast Cancer and Treatment Decisions
The stage of breast cancer indicates how far it has spread within the breast, to nearby lymph nodes and other tissues, and to distant organs such as the liver, lungs, and bones. The stage of breast cancer is one of the most important factors doctors use in making treatment recommendations and in predicting prognosis.

Carcinoma in Situ
Treatment of ductal carcinoma in situ usually includes surgery to the breast with or without radiation therapy. Chemotherapy or hormonal treatments are not generally required, and lymph node surgery is not usually performed. The prognosis from ductal carcinoma in situ is excellent: Almost 100 percent of women with this diagnosis are still alive five to ten years after their diagnosis. The main risk of recurrence is in the breast or chest tissue. Clinical studies have shown that tamoxifen may reduce risk of developing a new or recurring breast cancer.

Early Stage Invasive Breast Cancer: Stages I and II
Stage I and II invasive breast cancers are generally considered “early stage.” In stage I breast cancer, the tumor is smaller than 1 inch (2 centimeters) in size and the cancer has not spread to the lymph nodes under the arm or other sites beyond the breast. In stage II breast cancer, the tumor is 1 to 2 inches (2 to 5 centimeters) in size or it has spread to the lymph nodes under the arm.
Patients with early stage invasive breast cancer are usually treated initially with mastectomy or lumpectomy. In a lumpectomy, the surgeon removes the cancer and some surrounding tissue but leaves the rest of the breast intact. In a mastectomy, the surgeon removes the entire breast. The surgeon also removes underarm lymph nodes to determine if the breast cancer has spread. Most doctors recommend radiation therapy after breast lumpectomy. Patients may also be treated with chemotherapy or hormone therapies.

Advanced Stage Invasive Breast Cancer: Stage III
Stage III breast cancer is a more advanced cancer, but it has not spread outside of the breast or surrounding tissues or lymph nodes. Patients with advanced stage breast cancer usually are treated with chemotherapy followed by surgery and radiation therapy.

Metastatic Breast Cancer: Stage IV
In stage IV breast cancer, the tumor has spread to distant sites such as the liver, lungs, bones, brain, or lymph nodes outside of the underarm. This type of breast cancer is generally viewed as an incurable disease, although there is wide variation in the number of years that patients may live with this disease. Physicians and researchers are optimistic that some women with stage IV breast cancer may be cured with new forms of treatment.