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The Importance of Mammography

Mammography Guidelines for Women

Age 30 Begin screening mammography if your mother or sister had breast cancer before menopause
Age 40 Begin mammography whether or not you have experienced symptoms of breast cancer

A mammogram is an X-ray of the breast, usually taken from both the top and side view. During a mammogram, the breast is moderately compressed; this separates the breast’s fibrous and glandular elements to allow for clearer and more accurate breast pictures. Today’s modernized equipment is designed to minimize discomfort during the procedure.

Some women are reluctant to have a mammogram because they are concerned about radiation exposure. However, advances in mammographic technology ensure that the radiation exposure from an average mammogram is very minimal. The small degree of risk from radiation exposure during a mammogram is more than offset by the potential benefit of discovering breast cancer in its earliest stages.

While mammography remains the best and most accurate tool in detecting breast cancer, it is still not foolproof or perfect. Some cancers can be felt on physical examination but be invisible on the mammogram.

For that reason, women age 40 and older (or age 30 and older if there is a family history of breast cancer) should have their breasts examined every year by a doctor or trained health care professional.

By doing annual screening studies, small subtle changes in your breast can be found. It is also important to continue to perform monthly breast self-examinations.

If you notice a lump, a thickening, or any change the month following your mammogram, speak with your doctor right away. Do not wait until your next annual mammogram appointment. Keep in mind that a mammogram does not provide future protection against breast cancer.

Normal fatty breast with no unusual areas.
Normal fatty breast with no unusual areas.
Normal dense breasts with no unusual areas.
Normal dense breasts with no unusual areas.
Enlarged view of calcifications.
Enlarged view of calcifications.*
Cancer may appear as an irregular area.
Cancer may appear as an irregular area.

*Reprinted with permission from Teaching Atlas of Mammography by Laszlo Tabar and Peter B. Dean, 1985, Thieme Medical Publishers, NY, NY.

These photos show detailed images produced by mammography. One of the limitations of mammography is its inability to detect tumors in women with dense breasts (about one woman in 10). For these women; however, combining physical examination with mammography increases the detection rate to greater than 90 percent.


About half of the breast cancers found by mammography appear as clusters of microcalcifications. These are very small specks of calcium that cannot be felt but are visible on a mammogram. When they are clustered in one area in the breast, this could indicate an early sign of breast cancer.

The average size of a malignant (cancerous) cluster of calcifications seen on an annual screening mammo-gram measures 0.6 cm in diameter. Calcium deposits in the breast are not caused by calcium supplements commonly used to prevent osteoporosis.

Breast Cancer Sizes Detected by Mammogram and Self-Exam at Our Facility

0.2 - 0.3 cm Smallest size of a breast cancer visible on a mammogram
0.8 cm Mammograms can detect many other non-invasive cancers (such as DCIS) which are less than 1.0 cm
1.1 cm Average size of cancer found on a mammogram

1 cm Average size of cancer found by women who practice regular breast self-exam.
2.62 cm Average size of cancer detected in a physician physical exam for women who do not practice regular self-exam.

Lumps and Masses

The other half of the breast cancers found by mammography appear as a mass or abnormal density on the mammogram. Some cancers may be felt as a lump on physical examination and be invisible on the mammogram. In these cases, ultrasound (sound wave examination) is useful. This is especially true in dense, glandular breasts. A palpable lump should never be ignored because it is not visible on a mammogram. Such lumps should instead be aspirated, or drained with a needle. If the lump cannot be aspirated, it should be removed or biopsied.

Mammography remains the state-of-the-art tool for diagnosing breast cancer.

Other techniques of visualizing the breast are useful, but do not replace the mammogram. Breast ultrasound is extremely important for examining lesions, such as a fibrosistic condition. The ultrasound can also locate abnormalities in the breast that will help to direct a required biopsy. Also, an MRI (magnetic resonance imaging) can evaluate breast tissue and identify areas of abnormality. The usefulness of the MRI in breast cancer diagnosis continues to improve.

Mammograms for Breasts with Implants

Breast implants are used for augmentation (to make the breasts larger) or for reconstruction after mastectomy. The breast implant is usually filled with a fluid material such as saline, silicone or a combination of the two materials.

Because an X-ray beam is unable to penetrate the implant, special mammographic views are required to visualize the breast tissue that are obscured by the implant. One view requires that the technologist manipulate the implant by pulling the breast forward to compress the breast tissue without the implant in view. This may be uncomfortable, but does not harm the implant. Additionally, patients with breast implants will have standard mammogram films taken, which are also harmless to the implant.

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