How is breast cancer diagnosed?
Breast cancer is sometimes found after symptoms appear, but many women with early breast cancer have no symptoms. This is why getting the recommended screening tests (as described in the section "Can breast cancer be found early?") before any symptoms develop is so important.
If something suspicious is found during a screening exam, or if you have any of the symptoms of breast cancer described in the previous section, your doctor will use one or more methods to find out if the disease is present. If cancer is found, other tests will be done to determine the stage (extent) of the cancer.
Medical history and physical exam
If you think you have any signs or symptoms that might mean breast cancer, be sure to see your doctor as soon as possible. Your doctor will ask you questions about your symptoms, any other health problems, and possible risk factors for benign breast conditions or breast cancer.
Your breasts will be thoroughly examined for any lumps or suspicious areas and to feel their texture, size, and relationship to the skin and chest muscles. Any changes in the nipples or the skin of your breasts will be noted. The lymph nodes in your armpit and above your collarbones may be palpated (felt), because enlargement or firmness of these lymph nodes might indicate spread of breast cancer. Your doctor will also do a complete physical exam to judge your general health and whether there is any evidence of cancer that may have spread.
If breast symptoms and/or the results of your physical exam suggest breast cancer might be present, more tests will probably be done. These might include imaging tests, looking at samples of nipple discharge, or doing biopsies of suspicious areas.
Imaging tests used to evaluate breast disease
Imaging tests use x-rays, magnetic fields, sound waves, or radioactive substances to create pictures of the inside of your body. Imaging tests may be done for a number of reasons, including to help find out whether a suspicious area might be cancerous, to learn how far cancer may have spread, and to help determine if treatment is working.
A mammogram is an x-ray of the breast. Screening mammograms are used to look for breast disease in women who have no signs or symptoms of a breast problem. Screening mammograms usually take 2 views (x-ray pictures taken from different angles) of each breast.
Diagnostic mammograms are used to diagnose breast disease in women who have breast symptoms (like a lump or nipple discharge) or an abnormal result on a screening mammogram. A diagnostic mammogram includes more images of the area of concern. In some cases, special images known as cone or spot views with magnification are used to make a small area of abnormal breast tissue easier to evaluate.
A diagnostic mammogram can show:
- That the abnormality is not worrisome at all. In these cases the woman can usually return to having routine yearly mammograms.
- That a lesion (area of abnormal tissue) has a high likelihood of being benign (not cancer). In these cases, it is common to ask the woman to come back sooner than usual for her next mammogram, usually in 4 to 6 months.
- That the lesion is more suspicious, and a biopsy is needed to tell if it is cancer.
Even if the mammograms show no tumor, if you or your doctor can feel a lump, a biopsy is usually needed to make sure it isn't cancer. One exception would be if an ultrasound exam finds that the lump is a simple cyst (a fluid-filled sac), which is very unlikely to be cancerous.
If cancer is found, a diagnostic mammogram is often done to get more thorough views of the breasts. This is to check for any other abnormal areas that could be cancer as well.
Ultrasound, also known as sonography, uses sound waves to outline a part of the body. For this test, a small, microphone-like instrument called a transducer is placed on the skin (which is often first lubricated with ultrasound gel). It emits sound waves and picks up the echoes as they bounce off body tissues. The echoes are converted by a computer into a black and white image that is displayed on a computer screen. This test is painless and does not expose you to radiation.
Ultrasound has become a valuable tool to use along with mammography because it is widely available and less expensive than other options, such as MRI. Usually, breast ultrasound is used to target a specific area of concern found on the mammogram. Ultrasound helps distinguish between cysts (fluid-filled sacs) and solid masses and sometimes can help tell the difference between benign and cancerous tumors. In someone with a breast tumor, it can also be used to look for enlarged lymph nodes under the arm.
The use of ultrasound instead of mammograms for breast cancer screening is not recommended. However, clinical trials are now looking at the benefits and risks of adding breast ultrasound to screening mammograms in women with dense breasts and a higher risk of breast cancer.
Magnetic resonance imaging (MRI) of the breast
Breast MRI was discussed in detail in the section “Can breast cancer be found early?”
MRI can be used along with mammograms for screening women who have a high risk of developing breast cancer, or it can be used to better examine suspicious areas found by a mammogram. MRI is also sometimes used for women who have been diagnosed with breast cancer to better determine the actual size of the cancer and to look for any other cancers in the breast. It is not yet clear how helpful this is in planning surgery in someone known to have breast cancer. In someone known to have breast cancer, it is sometimes used to look at the opposite breast, to be sure that it does not contain any tumors.
If an abnormal area in the breast is found, it can often be biopsied using an MRI for guidance. This is discussed in more detail in the "Biopsy" section.
This test, also called a galactogram, sometimes helps determine the cause of nipple discharge. In this test a very thin plastic tube is placed into the opening of the duct in the nipple that the discharge is coming from. A small amount of contrast medium is injected, which outlines the shape of the duct on an x-ray image and shows if there is a mass inside the duct.
These tests may be done for the purposes of research, but they have not yet been found to be helpful in diagnosing breast cancer in most women.
Nipple discharge exam
If you are having nipple discharge, some of the fluid may be collected and looked at under a microscope to see if any cancer cells are in it. Most nipple discharges or secretions are not cancer. In general, if the secretion appears milky or clear green, cancer is very unlikely. If the discharge is red or red-brown, suggesting that it contains blood, it might possibly be caused by cancer, although an injury, infection, or benign tumors are more likely causes.
Even when no cancer cells are found in a nipple discharge, doctors cannot be sure breast cancer is not present. If you have a suspicious mass, it will be necessary to biopsy the mass, even if the nipple discharge does not contain cancer cells.
Ductal lavage and nipple aspiration
Ductal lavage is an experimental test developed for women who have no symptoms of breast cancer but are at very high risk for the disease. It is not a test to screen for or diagnose breast cancer, but it may help give a more accurate picture of a woman's risk of developing it.
Ductal lavage can be done in a doctor's office or an outpatient facility. An anesthetic cream is applied to numb the nipple area. Gentle suction is then used to help draw tiny amounts of fluid from the milk ducts up to the nipple surface, which helps locate the ducts' natural openings. A tiny tube (called a catheter) is then inserted into a duct opening. Saline (salt water) is slowly infused into the catheter to gently rinse the duct and collect cells. The ductal fluid is drawn through the catheter and sent to a lab, where the cells are looked at under a microscope.
Ductal lavage is not done if a women isn't at high risk for breast cancer. It is not clear if it will ever be useful. The test has not been shown to detect cancer early. It is more likely to be helpful as a test of cancer risk rather than as a screening test for cancer. More studies are needed to better define the usefulness of this test.
Nipple aspiration also looks for abnormal cells developing in the ducts, but is much simpler, because nothing is inserted into the breast. The device for nipple aspiration uses small cups that are placed on the woman's breasts. The device warms the breasts, gently compresses them, and applies light suction to bring nipple fluid to the surface of the breast. The nipple fluid is then collected and sent to a lab for analysis. As with ductal lavage, the procedure may be useful as a test of cancer risk but is not an appropriate screening test for cancer. The test has not been shown to detect cancer early.
A biopsy is done when mammograms, other imaging tests, or the physical exam finds a breast change (or abnormality) that is possibly cancer. A biopsy is the only way to tell if cancer is really present.
During a biopsy, a sample of the suspicious area is removed to be looked at under a microscope, by a specialized doctor with many years of training called a pathologist. The pathologist sends your doctor a report that gives a diagnosis for each sample taken. Information in this report will be used to help manage your care. For information to help you understand your pathology report, see the “Breast Pathology” section of our website or call 1-800-227-2345.
There are several types of biopsies, such as fine needle aspiration biopsy, core (large needle) biopsy, and surgical biopsy. Each has its pros and cons. The choice of which to use depends on your specific situation. Some of the factors your doctor will consider include how suspicious the lesion appears, how large it is, where in the breast it is located, how many lesions are present, other medical problems you might have, and your personal preferences. You might want to discuss the pros and cons of different biopsy types with your doctor.
Often, after the tissue sample is removed, the doctor will place a tiny metal clip or marker inside the breast at the biopsy site. The clip cannot be felt and should not cause any problems, but it is helpful in finding the area again on future mammograms and for surgery. Some patients who have cancer are given chemotherapy or other treatments before surgery that can shrink the tumor so much that it can’t be felt or seen on mammogram. The clip can be used to direct the surgeon to the area where the tumor was so the correct area of the breast can be removed.
Fine needle aspiration biopsy
In a fine needle aspiration (FNA) biopsy, the doctor uses a very thin, hollow needle attached to a syringe to withdraw (aspirate) a small amount of tissue from a suspicious area, which is then looked at under a microscope. The needle used for an FNA biopsy is thinner than the one used for blood tests.
If the area to be biopsied can be felt, the needle can be guided into the area of the breast change while the doctor is feeling (palpating) it.
If the lump can't be felt easily, the doctor might use ultrasound to watch the needle on a screen as it moves toward and into the mass.
A local anesthetic (numbing medicine) may or may not be used. Because such a thin needle is used for the biopsy, the process of getting the anesthetic may actually be more uncomfortable than the biopsy itself.
Once the needle is in place, fluid is drawn out. If the fluid is clear, the lump is probably a benign cyst. Bloody or cloudy fluid can mean either a benign cyst or, very rarely, a cancer. If the lump is solid, small tissue fragments are drawn out. A pathologist will look at the biopsy tissue or fluid under a microscope to determine if it is cancerous.
An FNA biopsy is the easiest type of biopsy to have, but it has some disadvantages. It can sometimes miss a cancer if the needle is not placed among the cancer cells. And even if cancer cells are found, it is usually not possible to determine if the cancer is invasive. In some cases there may not be enough cells to perform some of the other lab tests that are routinely done on breast cancer specimens. If the FNA biopsy does not provide a clear diagnosis, or your doctor is still suspicious, a second biopsy or a different type of biopsy should be done.
Core needle biopsy
A core biopsy uses a larger needle to sample breast changes felt by the doctor or pinpointed by ultrasound or mammogram.
When mammograms taken from different angles are used to pinpoint the biopsy site, this is known as a stereotactic core needle biopsy.
In some centers, the biopsy can be guided by an MRI scan.
The needle used in core biopsies is larger than the one used in FNA. It removes a small cylinder (core) of tissue (about 1/16- to 1/8-inch in diameter and ½-inch long) from a breast abnormality. Several cores are often removed. The biopsy is done using local anesthesia (you are awake but the area is numbed) in an outpatient setting.
Because it removes larger pieces of tissue, a core needle biopsy is more likely than an FNA to provide a clear diagnosis, although it might still miss some cancers.
Vacuum-assisted core biopsies
Another way to do a core biopsy is known as vacuum-assisted. For this procedure, the skin is numbed and a small incision (about ¼ inch) is made. A hollow probe is inserted through the incision into the abnormal area of breast tissue. The probe is guided into place using mammography, ultrasound, or MRI. A cylinder of tissue is then suctioned in through a hole in the side of the probe, and a rotating knife within the probe cuts the tissue sample from the rest of the breast. Several samples can be taken from the same incision. Vacuum-assisted biopsies are done as an outpatient procedure. No stitches are needed, and there is minimal scarring. This method usually removes more tissue than a regular core biopsy.
Surgical (open) biopsy
Usually, breast cancer can be diagnosed using needle biopsy. Rarely, surgery is needed to remove all or part of the lump for microscopic examination. This is referred to as a surgical biopsy or an open biopsy. Most often, the surgeon removes the entire mass or abnormal area as well as a surrounding margin of normal-appearing breast tissue. This is called an excisional biopsy. If the mass is too large to be removed easily, only part of it may be removed. This is called an incisional biopsy.
In rare cases, a surgical biopsy can be done in the doctor's office, but it is most often done in the hospital's outpatient department under local anesthesia (you are awake, but your breast is numbed), often with intravenous sedation (medicine given to make you drowsy). This type of biopsy can also be done under general anesthesia (you are asleep).
If the breast change cannot be felt, a mammogram may be used to place a wire into the correct area to guide the surgeon. This technique is called wire localization or stereotactic wire localization. After the area is numbed with local anesthetic, a thin hollow needle is placed in the breast, and x-ray views are used to guide the needle to the suspicious area. Once the tip of the needle is in the right spot, a thin wire is inserted through the center of the needle. A small hook at the end of the wire keeps it in place. The hollow needle is then removed. The surgeon can then use the wire as a guide to the abnormal area to be removed. The surgical specimen is sent to the lab to be looked at under a microscope (see below).
A surgical biopsy is more involved than an FNA biopsy or a core needle biopsy. It typically requires several stitches and may leave a scar. The larger the amount of tissue removed, the more likely it is that you will notice a change in the shape of your breast afterward.
Core needle biopsy is usually enough to make a diagnosis, but sometimes an open biopsy may be needed depending on where the lesion is, or if a core biopsy is not conclusive.
All biopsies can cause bleeding and can lead to swelling. This can make it seem like the breast lump is larger after the biopsy. This is generally nothing to worry about and the bleeding and bruising resolve quickly in most cases.
Lymph node biopsy
If the lymph nodes under the arm are enlarged (either by feel or on an imaging test like mammography or ultrasound), they may be checked for cancer spread. Most often, a needle biopsy is done at the time of the needle biopsy of the breast tumor.
Even if no lymph nodes are enlarged, the lymph nodes under the arm are usually checked for cancer spread when the breast tumor is removed at surgery. This is done with a sentinel lymph node biopsy and/or an axillary lymph node dissection. These procedures are described in detail in the section "How is breast cancer treated?"
Last Medical Review: 09/25/2014
Last Revised: 09/25/2014