What is a Mammography?
Mammography uses low doses of X-rays to take images of the breast tissues. It is a non-invasive medical imaging procedure. The image produced by a mammography is called mammogram. A specialized doctor (Radiologist) analyzes the test results.
A mammography is an effective tool in detection of breast cancer at an early stage where treatment is most likely to be successful. Mammogram help detect breast cancer long before any physical symptoms appear.
What is screening mammogram?
Screening mammograms is a voluntary early detection mammography, women above 45 years are recommended to take at regular intervals for early detection of breast cancer. This test allows detecting cancer cells even if lumps are not present.
Usually during a screening mammogram, a mammography machine takes four X-rays. Two X-rays of each breast. The first X-ray is taken at a horizontal level for the top view and the second X-ray is taken at an angle for the side view.
What is diagnostic mammogram?
Diagnostic mammograms are conducted if the results of the screening mammogram produced suspicious or inconclusive results. It is a more in-depth procedure to take a closer look at suspected areas.
Diagnostic mammogram maybe ordered by the doctor if clinical physical examination revealed a lump or if other related symptoms like unusual nipple discharge or pain are present
In a diagnostic mammogram “additional views” (additional X-rays) are taken from different viewing angle. The suspicious area detected in the screening mammogram is X-rayed with a magnification technique to produce a clearer image of the area in question.
If the results are inconclusive, then additional tests like ultrasounds, MRI or even biopsy maybe required
How often should you get a mammogram?
Recommendations and guidelines for the frequency and when to start routine mammograms have been updated recently.
As per the current American Cancer Society guidelines, women who are at average risk of developing breast cancer should start having regular yearly screening mammograms from the age of 45 years and continue until the age of 54 years.
From the age of 55, they should have a screening mammogram procedure every two years as long as the women is in good health and have a life expectancy of more than 10 years.
Previously American Cancer Society had recommended yearly screening mammograms and clinical breast examinations for women from the age of 40.
Who is considered at high risk for developing breast cancer?
A women who is consider at high risk of developing breast cancer is recommended to take yearly screening mammograms and MRI from the age of 30 to catch any developments at the earliest possible stage where the treatment is most effective.
The following factors are considered high risk for developing breast cancer:
- BRCA1 and BRCA2 are genes that produce special proteins that help in repairing damaged DNA which thereby help in suppressing cells that could lead to cancer. Women who have BRCA1 or BRCA2 gene mutations are considered a high-risk category.
- Someone who has very close relatives that has BRCA1 or BRCA2 gene mutations
- Women with family history of breast cancer.
- Women who has undergone radiation therapy to the chest area between a relatively young age of 10 and 30 years.
- Having certain rare inherited genetic disorders like Cowden syndrome, Li-Fraumeni syndrome or Bannayan-Riley-Ruvalcaba syndrome increases the risk of developing breast cancer. It important to mention to your doctor if any close relatives have any of these disorders.
How is a mammogram done?
A mammography machine consists of an X-ray generator and two plates that can be adjusted as per the height of the patient. The breast that is to be examined is placed between two plates that are attached to the mammography machine.
The breast tissues are compressed between the plates. Some women can experience discomfort or pain during the procedure. The compression is important because it spreads and flattens the breast tissues and allow for a clearer view of the breast tissues by limiting the movement of breast tissues during the test. It also reduces the amount of radiation required to produce a clear image.
The compression procedure is quick and can take as little as 20 to 30 seconds to complete. Usually during a screening mammogram, a mammography machine takes four X-rays.
To read more about the X-ray generator that forms the heart of a mammography machine read: Medical X-ray - 7 little known facts that will surprise you.
What can mammograms show?
The doctor examining the x-ray images (usually a radiologist) will check for abnormal changes in the breast tissues. They may also compare x-ray images from a previous mammography session to examine the changes.
An abnormal mammogram may show a lump or mass. They can also show calcification caused by deposits of mineral calcium that show as white spots on the x-ray image.
If anything suspicious is found, then the patient is called back for further evaluation. In many cases, the patient will get a clean report on the follow up tests and the doubts from the previous test can be dismissed as a false alarm.
What is Computer-Aided Detection (CAD) Mammograms?
CAD is a special software designed to examine mammograms. It is designed to assist radiologist in analyzing suspicious area in a mammogram. It acts like an extra pair of eyes for the radiologist.
The birth of mammogram
German surgeon Albert Salomon is considered as the father of mammogram. During 1913, he studied breast tissues from 3000 mastectomy (Surgical removal of breast tissues) specimens obtained from the morgue. By comparing breast X-rays images and the surgically removed breast tissues, he was able to spot abnormalities in breast tissues by observing an X-ray image.
He could successfully detected breast cancer using X-ray images by being able to differentiate between cancerous and noncancerous tumors. He also observed the different types of breast cancers and published a detailed report about his findings in 1913. However it was only many year later, his diagnostic method was used in clinical settings for the detection of breast cancer.
Mammograms do not prevent breast cancer, but can save lives
As a detection tool for breast cancer, it is a valuable tool in screening for breast cancer. One in eight women will develop breast cancer in their lifetime.
Breast cancer when detected in its early stages can reduce the risk of dying from the disease by more than 30%. If there is a family history of breast cancer patients in the family, screening should be considered much earlier than the recommended age of 45.
False negative results, Mammography machines are not perfect
Currently, screening by a mammography machine is one of the most recommended tests for early detection of breast cancers.
Unfortunately, this test is not perfect. There is a possibility that the test may miss (False negative results) the early detection of breast cancer in some women. Depending on various factors like age of the woman, density of the breasts the chances of false negative results could be anywhere between 16% and 30%. Women below the age of 50 are at a higher risk of having a false negative test results.
Doctors may fail to spot breast cancer on the mammogram because it may not be visible on the test results. False negative results can delay treatment and give false reassurance. To rule out a false negative result additional test like clinical breast exam, ultrasound scanning or MRI should be used whenever necessary.
False positive results
There is also a very high possibility of a false alarm (False positive results). The test may reveal a suspicious growth that may look like cancer and after further test it is revealed as being non-cancerous (benign).
After the initial screening test, the patient is called back to the doctor’s office to undergo furthers tests like diagnostic mammograms, ultrasound, MRI or biopsy. This can cause a lot of short-term anxiety and fear for the patient and their family members.
There is a possibility of 50-60% false positive results during a 10-year period and the possibility of a false positive result is at highest for the initial test. With subsequent test, the risk can be reduced by comparing results from the previous test.
Women over 50 are less likely to have false positive results than younger women.
Paradox of a positive test result
A positive test result from a diagnostic mammogram or tests as if biopsy means breast cancer is detected and treatment options needs to be laid out.
Some cancerous growth may stop growing after a certain period and can remain harmless for the rest of the woman’s life.
The problem is that doctors cannot clearly differentiate between cancer cells that may continue growing or may stop growing all together. Therefore, the only option is to treat them all. This means some women may get unnecessary treatments, which exposes them to the side effects of chemo and radiation therapy. The topic of patients being Over-diagnosed and being over-treated is a debatable topic.
It is difficult to estimate how many women are receiving unnecessary treatments, most credible estimates range from 0-10%. Unfortunately, with the current technology all positive results have to be treated equally without any exceptions.
Screening mammograms: Benefits outweigh the risks
There is much evidence to support the claim that annual screening mammograms are important. The benefits nearly always outweigh the possible risks associated with the test.
Over exposure to any type of Ionizing radiation (like X-rays) can increase the risk of developing cancer over time. The key factor is the amount of radiation received.
In fact, majority of women who die from breast cancer were not undergoing yearly screening mammography.
The amount of radiation received from an annual screening mammogram is similar to the amount of natural background radiation a woman living in US receives in 2 months.
No deodorants before mammography test
On the day of the test, it is recommended that the patient does not use any deodorants or antiperspirants. This is because these produces may contain metallic particles that may interfere with the test results by creating confusion on the x-ray image in the form of shadows or shades.
Other cosmetics like talcum powder, creams, lotions or perfumes are also not recommended. It is better to schedule the mammography test first thing in the morning.
Digital Mammography better for younger women
Previous generation mammography machines used films to capture x-ray images. New generation machines capturers the images digitally and the data is transferred to a computer.
Younger women tend to have denser breast tissue structure and this makes it difficult to examine the x-ray images because these dense tissues can hide abnormalities among normal tissue mass.
Digital images offer the advantage of being able to zoon in to the area of interest in such cases. The doctor can zoom in on the digital images to check suspicious areas or adjust the brightness and contrast of the image for better view.
It also easy to transmit the images via email incase the patient needs a second opinion from other doctors.
3D mammography or Digital Breast Tomosynthesis (Tomo)
This is the latest innovation in the field of mammography. The procedure takes a bit longer than a normal 2D mammography and the resulting radiation dose received is higher than a traditional 2D mammography but well within the guidelines and safe limits set by the FDA.
3D mammography machine looks and works very similar like a 2D mammography machine with the exception that the x-ray beam is shot at different angles by a moving arm of the machine all at once. The resulting series of thin slices of mammogram images (2D mammograms) are compiled using a computer to produce a very detailed image of the breast being examined
The test allows doctors to see a lot more details and small variations or abnormalities are detected very early.
Younger women benefit more from this new technology because they have denser breast tissues, which may make it difficult for 2D mammography machines to clearly identify abnormalities among normal tissue masses. The test is also recommended for high-risk women.
3D mammography increase the cancer detection rate (up to 40% increase), by reducing false negative results and also reduce the call back rate of the patient for reevaluation by reducing the number of false positive results (up to 40% reduction).
So far, the results have been very promising. There is less overall medical costs, less anxiety for the patient and more efficient monitoring and diagnostic results.