Screening for cancer: Self and clinical breast exam
| April 12, 2007
Screening for cancer: Self and clinical breast exam
Screening exams
Several exams can detect breast cancer. Some are used for routine screening. The term, "screening", as applied to cancer detection, means that the test is provided to a patient when the patient has no known abnormalities referable to the portion of the body that is being tested. If a patient herself detects a breast lump, then the subsequent evaluation performed by the physician is no longer considered a "screening test", since an abnormality was detected by the patient.
Breast self-exam
Experts no longer formally recommend that women routinely perform a self breast exam every month. But it should not be discouraged either, since many women first bring attention to a breast abnormality that they themselves detected. Checking your own breasts every month can be useful. You become more familiar with how your own breasts look and feel to the touch. Should a change arise, you may become aware of it sooner than if you weren't checking monthly.
If you do want to perform self breast exams, check your breasts on the same day every month, preferably seven days after your period begins. This is when the hormones from the ovaries are at their lowest levels and the breasts are least engorged. This is the best time to feel any irregularity that may be present.
Women who have gone through menopause should examine their breasts on the same day each month, such as on the first day of the month.
To perform a breast self-exam, begin by looking at your breasts in a mirror, first with your arms at your sides, then with your hands on your waist and bending forward slightly, and finally with your arms raised over your head. Look for asymmetries of the breast (one breast being larger than the other), dimpling of the skin, redness of the skin, new retraction of a nipple, evidence of nipple discharge or a lump in the armpit area. Discovery of any of these abnormalities demands prompt attention by a physician.
Then, either lying down or standing in the shower, examine your breasts for any bumps, lumps, or thickening. Place one arm behind your head and, with your opposite hand holding fingers flat, examine all areas of the breast. You can either proceed in a circular, organized fashion or methodically move up and down each breast, making sure no part is overlooked. First press lightly, then a bit more firmly and then very firmly in each area (the three-layer cake technique). You should then drop the arm, place the opposite arm behind your head, and examine your other breast in the same way.
Pay particular attention to the areas between the breasts (over the breastbone) and under the arms. Also, because some cancers occur in the nipple/areola area, feel this area carefully.
However, you shouldn't rely on self breast exam as the only way to screen for breast cancer. By the time you can feel a lump, it's probably half an inch or larger. Mammography, a type of x-ray examination of the breast, can detect cancers of smaller sizes, even those that cannot be felt or palpated by you or your physician.
Clinical breast exam
Because mammograms fail to detect 10%–15% of breast cancers, it's important to have an annual breast examination by a doctor or other health care professional. For the clinical breast examination, you will undress from the waist up and put on a gown. The doctor will first look at your breasts for any signs of cancer and then press on your breasts with a circular or up and down technique, similar to what is described above in self breast exam. Your doctor will also check for lymph nodes under your armpit (axilla) and around your collarbone.
Mammography
Mammography is the most common method for detecting abnormalities in the breast. This screening technique is an x-ray that uses very low levels of radiation. It can find 85%–90% of breast cancers. Mammography makes it possible to see tiny cancers that may measure as little as half a centimeter (about one-fifth of an inch). Generally, a lump can't be felt until it's at least twice that size. The abnormalities that show up on a mammogram may be benign or malignant.
Research shows that annual screening mammography performed on large populations of women who otherwise have no breast complaints may save lives in women ages 50 and older and suggests that it possibly reduces mortality in women ages 40–49. The American Cancer Society and other medical groups recommend that women have an annual mammogram starting at age 40. Women who are at high risk for breast cancer because of a family history or other factors may begin screening at an earlier age. (A family history of breast cancer may raise the possibility of performing genetic testing.) The downside of mammography is that it has increased the number of surgical biopsies in women who do not have breast cancer, and may increase a patient's anxiety level. As with any surgical procedure, complications may occur following a biopsy.
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Figure 3: What the radiologist sees The radiologist evaluating your mammogram may need to distinguish between a benign (noncancerous) mass and a suspicious mass. A benign mass (A) may appear as a low-density (translucent) area with clear borders. A suspicious mass (B) is more likely to be denser (more opaque) and to have irregular borders that radiate outward in a star-like pattern. The radiologist will also look for the small white dots known as calcifications. Tiny calcifications that appear in gravel-like clusters in one part of the breast (C) are considered suspicious while larger calcifications scattered individually throughout the breast are more likely to be benign. The finding of microcalcifications may indicate the presence of ductal carcinoma in situ.
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The mammography procedure. To obtain a clear picture of the breast tissue, a technician will ask you to stand with your breast on a platform and will pull the breast away from your body so the image can show as much breast tissue as possible.
The machine will compress your breast briefly between two plastic plates while it takes the x-ray picture. As soon as the x-ray is made, the plates automatically release. Horizontal and vertical views are made of each breast. Some women find the compression painful; most find it merely uncomfortable. Fortunately, the compression lasts only seconds.
If certain areas of the breast don't show up clearly on the mammograms after the initial reading by the radiologist (a doctor who specializes in interpreting these types of images), the technician may need to take additional views. This happens in 5%–10% of screening mammograms. Afterward, you will either be asked to wait until the radiologist has read each film, or you will receive the results in the mail a few days later.
If the results indicate a concern, the center will contact you by phone rather than mailing the results. It is important that you contact the radiologist or physician who ordered the mammogram if you have not been contacted about your results within a week. Although uncommon, letters in the mail may be lost or some other error may occur in getting results to you.
On a mammogram, the structures inside your breast appear in shades ranging from white to black. The white areas are mainly milk ducts. The hazy gray and black areas are fat tissue. Abnormalities appear as white spots of two types: densities or calcifications.
Densities. These abnormalities appear as light spots on the mammogram. If a density appears on a mammogram, the radiologist will examine it with two or more different mammographic views. A density may or may not indicate cancer. A density with a starburst shape (arms radiating outward from the center) is called "spiculated" and often indicates cancer. Noncancerous densities usually appear as a spot with a smooth outline and no arms radiating outward. If a density appears on a mammogram, the next step is usually a breast ultrasound.
Calcifications. These abnormalities appear as tiny, sand-grain-sized bright white dots. Most calcifications are benign. Benign calcifications are usually scattered randomly through both breasts, almost like a snowstorm. Or, benign calcifications may be clustered in a small space and are usually similar in size and may be coarse in appearance. If the calcifications appear to be benign, you and your doctors can monitor any further changes with yearly mammograms. Calcifications that appear as tiny dots of different sizes and shapes (pleomorphic) in a line (linearly arranged) are likely inside a duct and generally indicate cancer. More than 70% of suspicious mammographic findings that are biopsied turn out to be benign.
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BI-RADS assessment categories Category 0: Needs additional imaging Category 1: Negative Category 2: Benign finding Category 3: Probably benign finding — shorter mammogram schedule (usually six months) Category 4: Suspicious abnormality; biopsy should be considered Category 5: Highly suggestive of malignancy; biopsy warranted |
Assessing the mammogram. Radiologists use standard terminology for classifying the findings of a mammogram. The radiologist will use numbered categories to refer to the shape and margins of a mass, the appearance and distribution of calcifications, and the radiologist's level of suspicion that the abnormality represents a breast cancer. Such a classification system provides a common language for communication between radiologists, clinicians, and the women having the mammograms, regardless of where the procedure has been done. The categories were developed by the Breast Imaging Reporting and Data System. It is very likely that the letter you receive from either the radiologist or your physician who ordered the mammogram will include the BI-RADS scoring system in their report to you.
Magnetic resonance imaging (MRI)
A breast MRI is a high-resolution way of visualizing the breast without radiation. It is useful when a doctor suspects there is a tumor that is not showing up during a physical exam or mammography. It may also be used to determine the size and extent of a known tumor.
Breast MRI can be used in addition to mammography or ultrasound. Doctors use MRI when they suspect the presence of an "occult" breast cancer. This is when a woman has a swollen underarm lymph node that is found, by aspiration or biopsy, to contain cancer cells, yet no sign of cancer appears on a breast exam and mammogram. In most such patients, breast MRI can identify the site of the cancer if that particular cancer originated from the breast. MRI can also be used to examine the chest wall or pectoral muscles for suspected cancer, as these areas are hard to reach with mammography. As discussed below, breast MRI is useful in patients who have a genetic predisposition to breast cancer development or a strong family history.
Another feature of breast MRI is its ability to detect hidden second cancers in the breast of a woman who has already been diagnosed with one cancer. In some cases, the detection of a second cancer in the same breast may alter treatment approaches in selecting lumpectomy and radiation therapy (in the case of a single breast cancer) versus mastectomy (if more than one cancer is found in the breast).
A potential downside to using breast MRI is its ability to detect lesions that are not cancerous, but are suspicious enough to require a surgical biopsy procedure. Additional roles of breast MRI that are under evaluation include its use in detecting cancers in the opposite breast of a patient with one breast cancer already diagnosed.
Doctors also use breast MRI to determine the size and extent of a known tumor in a breast cancer patient. This is especially useful if the cancer is difficult to measure by mammography, as can be the case with an infiltrating lobular cancer. If you are taking anticancer drugs to shrink a tumor before surgery (a process called neoadjuvant therapy), MRI can help reveal whether the tumor is responding to the medication. In addition, MRI may be used to check for recurrences after lumpectomy.
Breast MRI requires special equipment designed specifically for breasts. To have an MRI, you lie very still within a large machine, face down, with your breasts suspended into a cushioned, bra-like holder. Your face and head are near the open ends of the magnet chamber. During the procedure, a dye is injected into your arm. Short bursts of high-frequency waves stimulate hydrogen atoms in cells to emit signals that are collected and turned into an image by a computer. The image is made in 5–10 sequences, each of which is 3–5 minutes long, with breaks in between. The entire examination takes about 45 minutes. The MRI machine makes loud clanking sounds. Ask for ear plugs.
MRI is expensive and somewhat technically difficult. It requires a specialized machine and radiologists experienced in its use. Nevertheless, major medical centers are finding that breast MRI, used in conjunction with mammography and ultrasound, can be a powerful tool for some patients.
This imaging method has some limitations, however. It can produce false positive readings in which a benign abnormality might resemble a cancer. Another drawback is that MRI is able to identify DCIS in only 50% of patients. Because of these problems, MRI is not recommended for routine screening of women at low or average risk of breast cancer. However, some breast centers use MRI and mammography to screen women who are at very high risk of breast cancer because they carry a mutation of BRCA1 or BRCA2. MRI tends to be more sensitive than mammogram in women with these genetic mutations. Women in this group may require an annual MRI as well as an annual mammogram, plus a clinical breast exam every six months.
Breast ductogram
Ductography, also called galactography, is a mammography technique used for evaluating the cause of spontaneous nipple discharge that occurs from a single duct in one breast. The procedure must take place when the fluid can be expressed from the breast so the correct duct can be examined.
The doctor inserts a slender, blunt-tipped catheter into the discharging duct and injects a small amount of contrast medium (dye that shows up on an x-ray image). The dye fills the duct, so when the mammogram is taken, the duct's shape and internal contour is visible. The injection of dye may produce a temporary feeling of "fullness" in the breast but doesn't usually cause pain or burning. If the radiologist sees a mass or other abnormality, that section of the duct can be surgically removed. If no distinct abnormality is apparent, the whole duct is removed for analysis. Most women with abnormal duct discharge do not have a malignancy.
Review Date: 2007-04-12
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