Overview
Cancer of the breast is the most frequently diagnosed cancer in U.S. women, but in can also occur in men.*
If you have been diagnosed with breast cancer, you probably have many questions about your disease, what treatments you are likely to receive, and what happens when treatment is completed. Breast cancer is the most common cancer in women. It usually occurs in the lobules of the breast, which is where milk is produced, or in the ducts that drain milk from the breast. In the United States, breast cancer occurs most frequently in women who have gone through menopause, but it can occur at any age. Breast cancer does occur in men, but it is rare.
Diagnosis of Breast Cancer
Breast cancer may be suspected for a number of reasons: you may have found a suspicious lump during a breast self-exam; your health care provider may have felt a lump during a clinical breast exam; or an abnormal area may have shown up on a screening test like mammography or breast MRI.
To determine whether an abnormal area is cancerous, the doctor will do a biopsy; that is, remove a small sample of the lump or suspicious area so it can be examined by a pathologist, a physician who specializes in looking at tissue to identify disease. Most often the sample is removed with a needle.
A core needle biopsy is the most common technique and gives a larger tissue sample for testing. A fine needle aspiration is less common and provides a smaller tissue sample. Sometimes an excisional biopsy is used if the doctor feels it is necessary to remove all of the tissue for analysis. This is usually done under local anesthetic in an outpatient procedure.
If the area to be biopsied cannot be readily located by touch, the doctor will use an imaging technique such as mammography or ultrasound
to help locate the suspicious area.
Breast Cancer Staging
There is a formal system for identifying how localized or widespread your cancer is. This system is called staging and ranges from stage 0 (most localized) to stage IV (spread to distant organs in your body). Staging is an important part of developing the best treatment plan for you. For a more detailed discussion of staging, see the Cancer Staging Guide.
The results of the biopsy will indicate the type of breast tissue cell where the cancer started. Common cancer types are ductal, lobular, and nipple, and each of these has subcategories. The tumor will also be assigned a grade from 1 to 3. Grade 1 indicates that the cells are most like those in normal breast tissue, while grade 3 is least like normal breast tissue. In general, higher grade tumors are more aggressive than lower grade tumors.
Your tumor will also be tested for estrogen and progesterone receptors, and whether high levels of the HER2 gene or protein are present, because the presence of these tumor markers suggests how quickly the tumor cells will grow and which therapies will be most effective. Because each responds differently to different drugs, these tumor markers will be used to determine the type of treatment that is most likely to be effective for you.
More Testing
If the biopsy indicates that you have breast cancer, you will be scheduled for tests that will help your doctor determine whether your tumor is confined to the area where it began (that is, whether it is localized) or whether it has spread to other parts of your body (metastasized). Your doctor also will take a detailed medical history and may request other tests to determine your health and whether certain treatments are appropriate for you.
Prognosis and Treatment Plan
Although all breast cancer is cause for concern, the effectiveness of your treatment depends on how localized it is and whether or how far it has spread in your body. Other factors that affect your outlook and treatment plan are the characteristics of your tumor cells; your estrogen and progesterone receptor tumor status; your HER2 tumor status; the cell type and grade of your tumor; your age; whether you are premenopausal or postmenopausal; and your general health.
In general, the more localized your breast cancer is, the better the chance that it can be cured with treatment. If the cancer has spread to different parts of your body, it is very unlikely your cancer can be cured; however, with treatment, it may be controlled and you may live a high-quality life for many years.
Treatment
Depending on stage of your disease, the characteristics of your tumor, and your general health, your treatment will include one or more of the following: surgery, radiation therapy, hormone therapy, chemotherapy, or targeted therapy. These are discussed further in the treatment sections of the patient summaries for each type of breast cancer.
Life After Treatment
After completion of your treatment, you will begin a period called follow-up. During this period, you will visit your doctor at regular intervals. The doctor will perform a physical examination, ask you about how you are feeling, and order tests to make sure that you remain healthy and so that any long-term effects of your breast cancer or its treatment can be addressed.
More Treatment Summaries on Breast Cancer
Treatment summaries that discuss specific types of breast cancer, which are also based on the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines™), are available. These summaries can help patients understand more about noninvasive breast disease (lobular carcinoma in situ or LCIS), noninvasive breast cancer (ductal carcinoma in situ or DCIS) and invasive breast cancer, which is categorized as inflammatory, stages I to III (sometimes called locoregional), and stage IV (or metastatic).
*Fewer than 1% of breast cancer cases occur in men. Because this summary is focused only on women’s breast cancer, men in search of information about male breast cancer may want to begin by visiting the National Cancer Institute’s overview of male breast cancer.