Treatment of Stage I Breast Cancer

Stage I breast cancer is a single area of cancer in your breast that is less than 2 centimeters (three-fourths inch) in size and has not spread outside your breast.

The majority of women with stage I breast cancer are cured by treatment with surgery and radiation therapy. But some women may benefit from more treatment with chemotherapy and/or antihormonal therapy. Treatment after surgery is called adjuvant therapy. It may further decrease the risk that your cancer will recur (come back).

Primary Treatment of Stage I Breast Cancer: Surgery and Radiation

The primary (initial) treatment of stage I breast cancer typically consists of surgery with or without radiation therapy. Surgery and radiation therapy are considered local treatments. They can prevent cancer recurrence in your affected breast and surrounding area, but they cannot treat cancer that has already spread to other parts of your body. Treatment that can reach the cancer anywhere in your body is called systemic treatment. Examples include chemotherapy and antihormonal therapy. This treatment may be given as adjuvant therapy (after primary treatment) for stage I breast cancer.

Surgery - Surgery for stage I breast cancers may consist of a mastectomy or lumpectomy. A mastectomy involves removal of your entire breast. A lumpectomy involves removal of the cancer and some surrounding tissue (called a surgical margin).

A lumpectomy alone is associated with a higher rate of cancer recurrence than a mastectomy. So if you have a lumpectomy, you will also be given radiation therapy to reduce the chances of recurrence due to tiny, invisible cancer cells left behind in the breast. The combination of a lumpectomy and radiation therapy is called breast-conserving therapy. Breast-conserving therapy is associated with a lower risk of a local cancer recurrence than a lumpectomy alone.

Mastectomy and breast-conserving therapy are the current standard of care for the local treatment of stage I breast cancers. Both are considered acceptable options. Most important is that studies find that women who have breast-conserving therapy and women who have a mastectomy have equivalent survival rates.

Surgery for early-stage breast cancer may also involve checking the lymph nodes in your armpit (axilla) to see if the cancer has spread outside your breast. This helps doctors tell the stage of your cancer. It is important for determining if you need additional treatments beyond local treatment, such as chemotherapy.

There are two ways to check these lymph nodes:

Axillary lymph node dissection - For more than 30 years, the standard of practice for telling the stage of breast cancer has included the removal of about 10 to 25 axillary lymph nodes to help determine if the cancer has spread. This procedure is called an axillary lymph node dissection. But a problem with this procedure is that it can have long-lasting side effects, including pain, limited motion of your shoulder, numbness, and swelling of your arm—also called lymphedema.

Sentinel lymph node biopsy - A new way of telling if cancer has spread to your lymph nodes is a sentinel lymph node biopsy. This procedure involves removing only a single lymph node—called the sentinel lymph node. This is the first lymph node to collect drainage from the area around the cancer.

Before surgery, blue dye and/or radioactive tracer is injected near the cancer. The dye drains from the area containing the cancer into the nearby lymph nodes through the sentinel node. The node containing the dye is removed during surgery and checked under a microscope to see if it contains cancer. Sentinel lymph node biopsy is becoming the standard for determining whether cancer has spread to the lymph nodes in women with localized breast cancer.

Research indicates that sentinel node biopsy appears to be just as effective in determining cancer spread to axillary lymph nodes as an axillary lymph node dissection. Also, it results in fewer side effects in women with early-stage breast cancer. Sentinel node biopsy is easier to perform than complete removal of the axillary lymph nodes and has a much lower incidence of lymphedema.

Radiation therapy - If you have a mastectomy, you probably will not be given radiation therapy. But if you have a lumpectomy, you will usually be given radiation therapy afterward.

Radiation therapy is typically given with a machine that delivers a beam of radiation deep into your body, where the cancer is. This technique is called external beam radiation therapy (EBRT). You usually have radiation treatments 5 days per week, for 5 to 6 weeks. Research indicates that radiation reduces the risk of a cancer recurrence when given after a lumpectomy and antihormonal therapy.

Adjuvant therapy - This is additional treatment given after your initial surgery and radiation therapy. The goal of adjuvant therapy is to get rid of any invisible cancer cells that remain after surgery (micrometastases). This reduces your risk of cancer recurrence. Adjuvant therapy for early-stage breast cancer may include chemotherapy, antihormonal therapy, and/or targeted therapy.

What are the potential benefits of the different types of adjuvant therapy?

Clinical trials have shown that treatment of early-stage breast cancer with adjuvant therapy reduces the risk of recurrence and improves survival time. This section discusses the potential benefits of the following types of adjuvant therapy:

Adjuvant chemotherapy - Chemotherapy involves the use of drugs to kill cancer cells. It is a standard adjuvant therapy for early-stage breast cancer. Chemotherapy may consist of single drugs or combinations of drugs—called regimens. It can be given by injection into your vein or taken by mouth in the form of a pill. If you have a diagnosis of breast cancer, you should be seeing an oncologist for chemotherapy.

Chemotherapy options - There are many different chemotherapy drugs and regimens. The CMF regimen (cyclophosphamide, methotrexate, and fluorouracil) was the first standard regimen used to treat early-stage breast cancer. It has been used for many years. CMF chemotherapy is typically given for six cycles over a period of about 4 to 6 months. In recent years, CMF has been used less in the United States. More recently, chemotherapy regimens containing anthracyclines, such as Adriamycin® (doxorubicin) and Ellence® (epirubicin), are used given data that suggests a slight improvement in outcome with this regimen versus treatment with CMF.

Taxanes - The taxanes are a group of chemotherapy drugs that include Taxotere® (docetaxel) and Taxol® (paclitaxel). Taxanes are typically combined with "AC" chemotherapy in the treatment of breast cancer. Treatment with combination chemotherapy that includes a taxane improves cancer-free survival in women with stage II or stage III breast cancer. The taxanes have also been shown to benefit women with node-negative breast cancer.

Adjuvant antihormonal therapy - The growth of some breast cancer cells can be prevented or slowed by reducing their exposure to the female hormone estrogen using antihormonal therapy. Estrogen is a hormone made by your ovaries and other tissue in your body. It serves many critical functions. These include developing your female sex organs in puberty, preparing your breasts and uterus for pregnancy in adulthood, and maintaining your cardiovascular and bone health. Without estrogen, your body cannot sustain pregnancy and is susceptible to heart disease and osteoporosis (thinning of your bones).

Estrogen can also make some cancers grow. Cells in your breasts, uterus, and other female organs are stimulated to grow when exposed to estrogen. These cells have areas on their surface called estrogen receptors. Estrogen in your blood binds to these receptors and stimulates the cells to grow. When cells that have estrogen receptors become cancerous, exposure to estrogen increases the cancer's growth. Cancers that have estrogen receptors are called estrogen receptor-positive (ER-positive) cancers.

Although antihormonal therapy can prevent or slow the growth of ER-positive breast cancer cells, reducing estrogen levels can also have side effects, such as thinner bones. Researchers have reported that adjuvant antihormonal therapy appears to benefit women with ER-positive breast cancer.

Several newer antihormonal therapies, called aromatase inhibitors, have proven to be superior to tamoxifen for the treatment of ER-positive breast cancer in postmenopausal women. Unlike tamoxifen, which blocks estrogen receptors on cells and prevents estrogen from helping the cancer grow, aromatase inhibitors prevent the production of an enzyme—called aromatase—that leads to the production of estrogen.

These drugs seem to have a different side effect profile than tamoxifen. If your doctor suggests antihormonal therapy, he/she may suggest one of three currently approved aromatase inhibitors.

Deciding Whether Adjuvant Therapy Is Right for You

Before deciding to receive adjuvant therapy, talk with your health care provider about the benefits and the risks for your particular cancer and circumstances. Understanding the answers to three questions will help determine if adjuvant therapy is a good option for you.

What are the chances that my cancer will recur without adjuvant therapy?

How will these chances be improved with adjuvant therapy?

What are the risks of adjuvant therapy?