Surgery
Surgery is the most common treatment for breast cancer. There are several types of surgery.

• Breast-sparing surgery: An operation to remove the cancer but not the breast is breast-sparing surgery. It is also called breast-conserving surgery, lumpectomy, segmental mastectomy, and partial mastectomy. Sometimes an excisional biopsy serves as a lumpectomy because the surgeon removes the whole lump.

The surgeon often removes the underarm lymph nodes as well. A separate incision is made. This procedure is called an axillary lymph node dissection. It shows whether cancer cells have entered the lymphatic system.

• Mastectomy: An operation to remove the breast (or as much of the breast tissue as possible) is a mastectomy. In most cases, the surgeon also removes lymph nodes under the arm. Some women have radiation therapy after surgery.

Sentinel lymph node biopsy is a new method of checking for cancer cells in the lymph nodes. A surgeon removes fewer lymph nodes, which causes fewer side effects. (If the doctor finds cancer cells in the axillary lymph nodes, an axillary lymph node dissection usually is done.)

Doctors use two types of radiation therapy to treat breast cancer. Some women receive both types:

• External radiation: The radiation comes from a large machine outside the body. Most women go to a hospital or clinic for treatment. Treatments are usually 5 days a week for several weeks.
• Internal radiation (implant radiation): Thin plastic tubes (implants) that hold a radioactive substance are put directly in the breast. The implants stay in place for several days. A woman stays in the hospital while she has implants. Doctors remove the implants before she goes home.

Chemotherapy uses anticancer drugs to kill cancer cells. Chemotherapy for breast cancer is usually a combination of drugs. The drugs may be given as a pill or by injection into a vein (IV). Either way, the drugs enter the bloodstream and travel throughout the body.

Some breast tumors need hormones to grow. Hormone therapy keeps cancer cells from getting or using the natural hormones they need. These hormones are estrogen and progesterone. Lab tests can show if a breast tumor has hormone receptors. If you have this kind of tumor, you may have hormone therapy.
This treatment uses drugs or surgery:

• Drugs: Your doctor may suggest a drug that can block the natural hormone. One drug is tamoxifen, which blocks estrogen. Another type of drug prevents the body from making the female hormone estradiol. Estradiol is a form of estrogen. This type of drug is an aromataseinhibitor. If you have not gone through menopause, your doctor may give you a drug that stops the ovaries from making estrogen.

• Surgery: If you have not gone through menopause, you may have surgery to remove your ovaries. The ovaries are the main source of the body's estrogen. A woman who has gone through menopause does not need surgery. (The ovaries produce less estrogen after menopause.)

Some women with breast cancer that has spread receive a biological therapy called trastuzumab. It is a monoclonal antibody. It is made in the laboratory and binds to cancer cells.