Radiation therapy (also called radiotherapy) uses high-energy rays to kill cancer cells. It affects cells only in the part of the body that is treated. Radiation therapy may be used after surgery to destroy breast cancer cells that remain in the area.
Doctors use two types of radiation therapy to treat breast cancer. Some women receive both types:
- External radiation therapy: The radiation comes from a large machine outside the body. You will go to a hospital or clinic for treatment. Treatments are usually 5 days a week for 4 to 6 weeks. External radiation is the most common type used for breast cancer.
- Internal radiation therapy (implant radiation therapy or brachytherapy): The doctor places one or more thin tubes inside the breast through a tiny incision. A radioactive substance is loaded into the tube. The treatment session may last for a few minutes, and the substance is removed. When it’s removed, no radioactivity remains in your body. Internal radiation therapy may be repeated every day for a week.
Hormone therapy may also be called anti-hormone treatment. If lab tests show that the tumor in your breast has hormone receptors, then hormone therapy may be an option. (See Lab Tests with Breast Tissue.) Hormone therapy keeps cancer cells from getting or using the natural hormones (estrogen and progesterone) they need to grow.
Options before menopause
If you have not gone through menopause, the options include:
- Tamoxifen: This drug can prevent the original breast cancer from returning and also helps prevent the development of new cancers in the other breast. As treatment for metastatic breast cancer, tamoxifen slows or stops the growth of cancer cells that are in the body. It’s a pill that you take every day for 5 years.
In general, the side effects of tamoxifen are similar to some of the symptoms of menopause. The most common are hot flashes and vaginal discharge. Others are irregular menstrual periods, thinning bones, headaches, fatigue, nausea, vomiting, vaginal dryness or itching, irritation of the skin around the vagina, and skin rash. Serious side effects are rare, but they include blood clots, strokes, uterine cancer, and cataracts. You may want to read the NCI fact sheet Tamoxifen.
- LH-RH agonist: This type of drug can prevent the ovaries from making estrogen. The estrogen level falls slowly. Examples are leuprolide and goserelin. This type of drug may be given by injection under the skin in the stomach area. Side effects include hot flashes, headaches, weight gain, thinning bones, and bone pain.
- Surgery to remove your ovaries: Until you go through menopause, your ovaries are your body’s main source of estrogen. When the surgeon removes your ovaries, this source of estrogen is also removed. (A woman who has gone through menopause wouldn’t benefit from this kind of surgery because her ovaries produce much less estrogen.) When the ovaries are removed, menopause occurs right away. The side effects are often more severe than those caused by natural menopause. Your health care team can suggest ways to cope with these side effects.
Options after menopause
If you have gone through menopause, the options include:
- Aromatase inhibitor: This type of drug prevents the body from making a form of estrogen (estradiol). Examples are anastrazole, exemestane, and letrozole. Common side effects include hot flashes, nausea, vomiting, and painful bones or joints. Serious side effects include thinning bones and an increase in cholesterol.
- Tamoxifen: Hormone therapy is given for at least 5 years. Women who have gone through menopause receive tamoxifen for 2 to 5 years. If tamoxifen is given for less than 5 years, then an aromatase inhibitor often is given to complete the 5 years. Some women have hormone therapy for more than 5 years. See above for more information about tamoxifen and its possible side effects.
Chemotherapy uses drugs to kill cancer cells. The drugs that treat breast cancer are usually given through a vein (intravenous) or as a pill. You’ll probably receive a combination of drugs.
You may receive chemotherapy in an outpatient part of the hospital, at the doctor’s office, or at home. Some women need to stay in the hospital during treatment.
Some anticancer drugs can damage the ovaries. If you have not gone through menopause yet, you may have hot flashes and vaginal dryness. Your menstrual periods may no longer be regular or may stop. You may become infertile (unable to become pregnant). For women over the age of 35, this damage to the ovaries is likely to be permanent.
On the other hand, you may remain able to become pregnant during chemotherapy. Before treatment begins, you should talk with your doctor about birth control because many drugs given during the first trimester are known to cause birth defects.
Some women with breast cancer may receive drugs called targeted therapy. Targeted therapy uses drugs that block the growth of breast cancer cells. For example, targeted therapy may block the action of an abnormal protein (such as HER2) that stimulates the growth of breast cancer cells. (For information about HER2, see Lab Tests with Breast Tissue.)
Trastuzumab (Herceptin®) or lapatinib (TYKERB®) may be given to a woman whose lab tests show that her breast tumor has too much HER2:
- Trastuzumab: This drug is given through a vein. It may be given alone or with chemotherapy. Side effects that most commonly occur during the first treatment include fever and chills. Other possible side effects include weakness, nausea, vomiting, diarrhea, headaches, difficulty breathing, and rashes. These side effects generally become less severe after the first treatment. Trastuzumab also may cause heart damage, heart failure, and serious breathing problems. Before and during treatment, your doctor will check your heart and lungs. The NCIfact sheet Herceptin® (Trastuzumab) has more information.
- Lapatinib: The tablet is taken by mouth. Lapatinib is given with chemotherapy. Side effects include nausea, vomiting, diarrhea, tiredness, mouth sores, and rashes. It can also cause red, painful hands and feet. Before treatment, your doctor will check your heart and liver. During treatment, your doctor will watch for signs of heart, lung, or liver problems.