Mammograms and Other Breast Imaging Tests

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Mammograms in special circumstances

Mammograms in younger women

Mammograms are more difficult to read in younger women, usually because their breast tissue is dense and this can hide a tumor on an x-ray. Since most breast cancers occur in older women, this is usually not a problem. Screening mammograms are not recommended for average-risk women under age 40.

In some younger women who are at high risk for developing breast cancer (due to a gene mutation, a strong family history, or other factors), yearly breast MRIs and mammograms are recommended. For most of these women, screening should begin at age 30 years and continue for as long as the woman is in good health. But because the evidence about the best age at which to start screening is limited, this decision should be based on discussions between patients and their health care providers, taking into account personal circumstances and preferences.

Our document called Breast Cancer: Early Detection gives more details about the American Cancer Society breast cancer screening recommendations. It also tells you more about figuring out your breast cancer risk.

Mammograms after breast-conserving treatment

What is breast-conserving treatment?

Removing the entire breast (mastectomy) is one way of treating breast cancers. But today, most breast cancers can be treated just as well with breast-conserving treatment (BCT), which does not remove the entire breast.

Partial mastectomy (sometimes called lumpectomy) is another name for BCT. This procedure removes the cancerous tumor and some of the surrounding normal breast tissue.

BCT is almost always followed by radiation treatment.

A woman who has had BCT will need to continue having regular mammograms of both breasts.

Mammogram plans after breast-conserving treatment

Most radiologists recommend that women have a mammogram of the treated breast 6 months after radiation treatment is finished. Radiation and surgery both cause changes in the skin and breast tissues. These changes show up on the mammogram, making it harder to read. The changes usually peak 6 months after the radiation is completed. The mammogram done at this time serves as a new baseline for the affected breast for that woman. Future mammograms will be compared with this one, to help the doctor follow up on healing and check for recurrence (the cancer coming back).

Depending on the results, the next exam for that breast is often 6 months later. Experts differ on the best follow-up plan from this point on. Some prefer a mammogram of the treated breast every 6 months for 2 to 3 years; others suggest that yearly mammograms are enough. Each woman should talk with her doctor about the plan that is best for her. The opposite breast still needs yearly mammograms.

Mammograms after mastectomy

Without breast reconstruction

Total or simple mastectomy removes all of the breast tissue, including the nipple, but does not remove underarm lymph nodes or chest muscle tissue beneath the breast. Sometimes this surgery is done for both breasts (a double mastectomy), most often as preventive surgery in women at very high risk for breast cancer.

Modified radical mastectomy removes the breast, skin, nipple, areola, and most of the lymph nodes under the arm on the same side, leaving the chest muscles intact.

Radical mastectomy is surgery for breast cancer in which the breast, chest muscles, and all of the lymph nodes under the arm are removed. This surgery is rarely used today. It’s mainly used when the cancer has spread to the chest muscles.

Women who have had total, modified radical, or radical mastectomy for breast cancer need no further routine screening mammograms of the affected side. (If both breasts are removed, they don’t need mammograms at all.)

Mammograms are usually continued on the unaffected breast each year. This is very important, because women who have had one breast cancer are at higher risk of developing a new cancer in the other breast.

One type of mastectomy that does require a follow-up mammogram is the subcutaneous mastectomy, also called skin-sparing mastectomy. In this operation, the woman keeps her nipple and the tissue just under the skin. Enough breast tissue is left behind to require yearly screening mammograms in these women.

Any woman who is not sure what type of mastectomy she has had or whether she needs mammograms should ask her doctor.

With breast reconstruction

Women who have had a breast fully removed and reconstructed (rebuilt) with silicone gel or saline implants do not need routine mammograms. If the woman has had a subcutaneous mastectomy (discussed above), yearly mammograms are still needed.

After mastectomy, some women choose to have their breast shape rebuilt using tissue from their own bodies. There are several types of reconstruction procedures (for information about different flap procedures, see our document Breast Reconstruction after Mastectomy). A patient who has had a complete (not subcutaneous) mastectomy followed by reconstruction needs no further screening mammograms on the affected side. But if there’s an area of the reconstructed breast that is of concern on the physical exam, a diagnostic mammogram may be done. Further imaging with ultrasound or MRI may also be helpful.

Mammograms in women with breast implants

Women who have implants are a special challenge for mammogram screening. The x-rays used for imaging the breasts cannot go through silicone or saline implants well enough to show the breast tissue that is over or under it. This means that the part of the breast tissue covered up by the implant will not be seen on the mammogram.

In order to see as much breast tissue as possible, women with implants have 4 extra pictures (2 on each breast) as well as the 4 standard pictures taken during a screening mammogram. In these extra x-ray pictures, called implant displacement (ID) views, the implant is pushed back against the chest wall and the breast is pulled forward over it. This allows better imaging of the front part of each breast. Implant displacement views do not work as well in women who have had hard scar tissue form around the implants (contractures). They are easier in women whose implants are placed underneath (behind) the chest muscle.

Although these women do have more pictures taken at each mammogram, the guidelines for how often women with implants should have screening mammograms are the same as for women without them. (See Breast Cancer: Early Detection for the American Cancer Society’s breast cancer screening guidelines.)

A ruptured (burst) implant can sometimes be diagnosed on a mammogram, but a ruptured implant will often look normal. Magnetic resonance imaging (MRI), on the other hand, is extremely good at finding an implant rupture. MRI is the best way to check the implant itself, while mammography is still the best test for evaluating breast tissue. See the section “Other breast imaging tests” in this document for more information on MRI.

Very rarely, mammograms can cause an implant to rupture. It’s important to tell the technologist before your mammogram if you have implants.


Last Medical Review: 12/10/2013
Last Revised: 06/10/2014