Breast Cancer Information from Breast Cancer Alliance of North Texas

The breast is composed of lobules that make milk. The milk is then carried to the nipple by the breast ducts. We now think that breast cancer starts where the duct and the lobule meet. If breast cancer starts in the duct, it is known as ductal carcinoma. This accounts for about 80% of cancers. If the cancer starts in the lobules, it is known as lobular carcinoma. This accounts for 10 - 15% of cancers. Either type of cancer can be in situ or invasive. In situ cancers, by definition, cannot spread to the rest of the body. Invasive cancers have the potential to spread.

Most surgeons do not consider lobular carcinoma in situ to be an actual cancer, but rather to be a marker for an increased risk of breast cancer over a lifetime. Ductal carcinoma in situ, otherwise known as DCIS, is a cancer that starts in the milk ducts and can not spread to the rest of the body. It is usually treated by either lumpectomy (removal of the tumor with a rim of normal tissue) and radiation therapy or by mastectomy (removal of the breast). We are able to use lumpectomy about 75 - 80% of the time to remove the cancer. The other 20 - 25% of the time, we perform mastectomy. A mastectomy is usually indicated if the tumor size is large compared to breast size, if there is more than one area of cancer within the breast, or if the patient can not undergo radiation therapy.

Invasive cancers have the potential to spread to the rest of the body. Invasive ductal carcinoma is the most common kind of breast cancer, and accounts for about 80% of all breast cancers diagnosed each year. Invasive lobular carcinoma accounts for 10 - 15% of all breast cancers. This type of cancer is often harder to find by mammography. Both types of cancers are treated in the same way - by either mastectomy or lumpectomy and radiation therapy and by the removal of at least some of the lymph nodes under the arm (this is usually the first place breast cancer spreads if it leaves the breast). Both cancers have similar prognosis; one is not worse than the other.

Prognosis in breast cancer depends on the stage of the cancer. This is a simplified description of the stages of breast cancer:

For most patients, we check whether or not the lymph nodes under the arm are involved by cancer by performing a procedure known as a SENTINEL LYMPH NODE BIOPSY. The entire breast drains to a certain number of lymph nodes under the arm. These lymph nodes that are first in the line of drainage of the breast are known as sentinel lymph nodes. Different people will have a different number of sentinel lymph nodes. Most people will have between one and six sentinel lymph nodes.

Prior to surgery, a small amount of radioactive tracer is injected over the tumor. In the operating room, blue dye is also injected into the skin overlying the tumor. During the operation, any lymph nodes that contain radioactivity or blue dye are sent to the pathologist to be examined under the microscope.

The results of these studies usually take four or five days to come back. If the sentinel lymph nodes do not contain cancer, it is unlikely that any of the other lymph nodes contain tumor, and no other treatment is needed under the arm. If the sentinel lymph nodes contain cancer, the remaining lymph nodes are usually removed to make sure that no tumor is left behind.

About four weeks after surgery, if the tumor is larger than 1 cm, or if a lymph node is involved, most patients undergo chemotherapy. Chemotherapy is given by a medical oncologist one day every three weeks for four to six months.

If breast conservation therapy (a lumpectomy) is done, patients undergo radiation therapy. Radiation therapy starts about one month after the last chemotherapy treatment is done. It is given every day for five to six weeks by a radiation oncologist. Radiation therapy does not make you sick or make your hair fall out. There are certain special circumstances when radiation therapy is given after a mastectomy, but this is unusual.

If a patient's tumor is responsive to hormones, the patient may be placed on a medicine call tamoxifen. This is a pill that is taken once or twice a day for five years. This reduces the rate of cancer recurrence by a half, not just for the affected breast, but also for the opposite breast.