What is a mammogram or mammography? Definition

Mammography is the X-ray imaging process of using low-energy X-rays to examine the human breast for diagnosis and screening for early detection of breast cancer, which typically presents as characteristic masses or microcalcifications on the mammogram. A mammogram is a low-dose X-ray of breast tissue. This is the most effective screening test for breast cancer.

Together with regular clinical exams conducted by the doctor and monthly breast self-examinations, mammogram, an imaging procedure, plays an important and beneficial key role in the diagnosis of breast cancer early when it is most treatable.

It is low-dose X-ray imaging to detect any abnormality in the breast tissue and is a vital tool in breast cancer diagnosis.

Undergoing an annual mammogram is important after the age of 40 years. According to breast cancer statistics, it is the second most common cancer for women in the United States, after skin cancer.

According to The American Cancer Society’s estimates for breast cancer in the United States for 2021:

  • About 281,550 women will be newly diagnosed with invasive breast cancer
  • Of these, about 49,290 new cases of ductal carcinoma in situ (DCIS) will be diagnosed, and
  • About 43,600 women will succumb to breast cancer

These figures underline the importance of mammography because of its role in detecting breast cancer early.

Mammography screening

Breast cancer screening means investigating a woman’s breasts for cancer before the appearance of symptoms of the disease.

Screening mammograms are done as a normal screening procedure in women who have no symptoms or signs of breast cancer. In this procedure, two X-rays are taken of each breast — a head-to-foot facing view and a side-angled view.

Mammograms make it possible to detect tumors, which are not felt on breast examination. They can detect even microcalcifications and small lumps that could indicate breast cancer. Results are obtained on film.

It is especially indicated in women who are prone to this cancer and harbor risk factors. The two most important risk factors in women are advancing age and familial tendency.

Mammogram screening can help detect breast cancer early when it becomes easier to treat and the prognosis and survival vastly improve.

Risks of screening mammograms and accuracy

Mammography accurately diagnoses breast cancer in about 78% of all imaged women, while in diagnostic mammograms, the accuracy rises to about 83% for women over 50.

Mammogram risks and limitations include:

  • Exposure to low-dose radiation. Repeated exposure every year or so can result in overexposure. However, the benefits of regular mammograms outweigh the risks posed by this amount of radiation.
  • False-negative results. This means that the results of the mammogram may be normal even though breast cancer is present. 20% of the mammography results are false negatives. This usually happens in dense breasts. A dense breast contains more glandular tissue and connective tissue, which appear similar to a tumor on an X-ray film, thereby leading the radiologist to miss the tumor.
  • False-positive results. This occurs when a tumor is diagnosed on the mammogram even though it is not present. All abnormal reports, therefore, need to be confirmed by additional tests such as diagnostic mammograms, ultrasound of the breast, and biopsy. False-positive results are seen in younger women, women who are on estrogen as in post-menopausal treatment, and women who have undergone breast biopsies before.
  • Failure rate. Screening mammograms cannot detect all tumors. The failure rate is about 20%.
  • The cure rate is not 100%. Some tumors diagnosed on mammography can cause death. This is true of fast-growing and aggressive tumors.

To reduce the risk of false positive and false negative results, a highly prone woman may be advised to go in for digital mammography and tomosynthesis.

Mammogram procedure

You should remove all jewelry around the neck and chest and wash off any deodorant, powder, or perfume before the mammogram as they can disturb the clarity of the film.

You have to expose the upper part of your body and you are made to stand in such a way that the breasts are placed on a flat panel.

The technologist gently but firmly places another plate on the breast from above so that the breast is firmly compressed between the two plates. The compression of the breast is necessary to get a good-resolution image on the X-ray film.

Two mammograms are taken from different angles for each breast – one from above and below and another is taken sideways. Any pain or discomfort you feel after this procedure is only temporary. This procedure takes about 20 minutes.

You will then wait while the technologist checks the quality of the four X-rays to make sure the pictures do not need to be taken again.

Each woman’s mammogram may appear a little different because all breasts are not alike and are a little different.

Are mammograms painful?

Every woman has a different experience while undergoing a mammogram. Some women may feel slight pain or discomfort during the procedure, while others may not feel anything at all.

However, a little discomfort is usually felt by most women during the mammogram procedure, which is caused by the pressure of the plates against your breasts. This is normal and does not indicate any abnormality in the breast.

Diagnostic mammogram

A screening mammogram, as explained above, is an x-ray of the breast. It is routinely done to detect breast cancer in women who have no apparent symptoms.

Diagnostic mammograms, on the other hand, are performed after any suspicious results are seen on screening or after you present some signs of breast cancer such as a lump, tenderness, nipple discharge, or skin changes in one or both breasts.

On any abnormality being detected on a screening mammogram or a clinical examination or the presence of symptoms and signs of breast cancer, your doctor will recommend a diagnostic mammogram for further evaluation of the abnormality.

Diagnostic mammograms focus on a localized area of the breast that has been identified by the plain mammogram as abnormal. It is more specialized and requires more views to be taken. The results are obtained on film.

The diagnostic mammogram confirms whether the changes are benign (non-cancerous) or malignant. Accordingly, treatment and further tests are conducted. This diagnostic procedure helps in early diagnosis, prompt treatment, and increased possibility of cure.

The diagnostic mammogram is done by a radiographer (medical imaging technologist), who has specialized in the field of mammography. The results are read and interpreted by a radiologist

Who should undergo a mammogram? Guidelines

Film mammograms have limited use in women under the age of 35 years as their breast tissue is denser and an abnormality is, therefore, difficult to detect.

Women with an average risk should get their mammogram done every year or two beginning at the age of 40 years. Professional opinions differ as some advise it after the age of 50 years.

Women with high risk should start mammogram screening before the age of 40 years and should regularly undergo mammography every one or two years. However, in both cases, the doctor will be the best judge to advise.

Mammogram results

The background of the X-ray image will be black, and the breast will show up in gray and white. Denser tissue and the connective tissue and glands show up white. A tumor is made up of dense tissue and will also appear white. This can make it harder to detect abnormalities on a mammogram in very dense breasts.

Radiologists use a standard system in medical reporting to describe mammogram screening and diagnostic findings called the Breast Imaging Reporting and Data System (BI-RADS). This system gives the results numbered 0 through 6.

If the radiologist sees a suspicious mass, he will give the mammogram a BI-RADS score of 4, which will mean there is an abnormality that doesn’t appear to be cancer, but the possibility exists. He will still advise a biopsy for confirmation. If he sees an image highly suggestive of a malignant tumor, he will give a BI-RADS score of 5.

The mammogram report is made available to the patient or her doctor on the same day. Some centers may, however, take one day more depending on the availability of the reporting radiologist.

The results of a mammogram are produced as black-and-white images on an X-ray film. A digital mammogram displays the image electronically as a video or an image on the computer.

Abnormal mammogram

Possible abnormal findings on a mammogram may include the following:

  • Calcification (calcium deposits) in the ducts or lobular tissue of the breast is usually due to cell debris, cell secretion, trauma, foreign body, or previous radiation exposure. Macro deposits usually are benign and due to aging or a benign condition such as fibroadenoma. Microcalcifications are usually malignant.
  • Growths or lumps. Dense areas on the X-ray film can indicate a tumor or glandular tissue with many glands.
  • Distorted dense areas may indicate a tumor that has invaded neighboring tissue.
  • A dense area in one breast only indicates an abnormality.
  • Changes in dense areas since the last mammogram are abnormal.

All such abnormal results will prompt your doctor to rule out malignancy by further testing with an ultrasound or a breast biopsy.

It is important to know that more than 80% of breast tumors are non-malignant and as such one should not presume the worst and start worrying about it.

According to the American Cancer Society, less than 1 in 10 women who have an abnormal mammogram and are called back for additional tests have cancer.

The digital mammogram is an improved method over its conventional type as it allows the doctor to view magnified images on the computer.

The average cost for a screening mammogram in the United States ranges from about $100 to $250. A diagnostic mammogram can cost more. However, you may be eligible for free or low-cost screenings if you meet certain criteria.