This is the most common and popular test in breast cancer. It is instrumental in breast cancer screening, evaluation of the cancer, diagnosis of the cancer type, spread and monitoring of the breast cancer. Mammogram is an X- ray of the breast which is quite accurate and a safe procedure. It has now been a good 40 years that this technique has been in use for breast cancer.
As a part of cancer screening it is recommended that this test should be done periodically every year to check for any early symptoms of breast cancer. In diagnosis these mammograms become more focused on one area of the breast and concentrate on the affected region of the breast. In a diagnostic mammogram as compared to a screening mammogram more images are generated by the radiologist and the technician.
The most prominent institutes and organizations are of the opinion that starting age 40 all the women populations of the world should undergo mammogram screening for breast cancer.
The mammogram screening should be a part of the annual health check up of all women, particularly so if the woman falls in the category of “high-risk” for breast cancer development. The high risk category is defined by the genetic disposition and the medical history of the woman. For such women there should be an aggressive screening program which is inclusive of MRI/ultrasound and a mammogram.
This test evaluates early signs of breast cancer and as such it has been known to bring down the mortality due to breast cancer by 35% in the women of age group beyond 50. As these cancers are diagnosed there are improved treatment choices with better prognosis. When the cancer is diagnosed early, it is predominantly localized and hasn’t spread to other parts of the breast. Thus, localized tumor growths can be removed surgically without performing a complete mastectomy. In a mastectomy entire breast is removed, thus diagnosing breast cancers early with mammography resulted in many women being able to keep their breasts. One disadvantage of mammogram is that in a dense breast tissue, it can give a “false negative” result. In a “false negative” result, abnormal tissue is hidden with the normal tissue and is not seen in the breast X-ray image. It can also sometime show a normal tissue to appear as abnormal which is then termed as a “false positive”. A false positive may lead to more tests and natural stress. Thus it is suggested that women practice self breast examination accompanied by regular checks by experienced medical professionals. In modern mammograms, risk to radiation exposure is minimal.
Usually for women population at large this test should be done annually after the age of 40. For high risk women – “women with a family history of breast cancer, even ovarian cancer, women who have had radiation exposure”; it is suggested that the breast cancer screening should begin at an early stage – around 30.
1. Film screen mammography
2. Digital mammography – full field digital mammography (FFDM)
The process or the technique of performing both the types of mammography is the same. The difference lies in the method in which the images are captured. If the images are captured in the photographic films, it is called as film screen mammography and if the images are recorded digitally in the computer, it is called as digital mammography.
The mammogram machine has two clear plates which are connected to a camera. In the test the technologist places and positions the breast between the two clear plates by compressing the breasts. The highly specialized camera which is attached to the two clear plates, takes images of the breast tissue in totality from two opposite directions. This process is repeated on the second breast. To cover the breast in totality at times more than two images may be captured.
Due to the compressing of the breast, mammography may be painful and highly uncomfortable for some women. Though it is not a very painful procedure and involves a discomfort of 20 minutes or so. The compression of breasts is necessary to flatten out the tissue so that the X-ray beam is able to penetrate enough tissue layers for a good image. If a mammography is being done for diagnostic purposes, more images of the breast are captured as compared to a screening mammography. It also takes longer due to the same reason than a regular 20 minute screening mammography.
It is a minimalistic radiation exposure procedure making it quite safe for the body. During the mammography, if there is any scarring on the breast the same should be told to the doctor. This information is required so that the doctor is able to make out these scars from any other abnormality of the breast. This earlier scarring can be due to any reason like a benign biopsy or a previous breast reduction surgery. Also sometime small metal tapes are attached to the skin to mark breast cancer surgery site from before.
A mammography report shall be read by a radiologist, a radiologist is a medical doctor specialist in reading and analyzing images of the body parts and consequently detecting and diagnosing any medical disease or condition. Also a “CAD” which is – computer aided detection can be done on reports. In it a computer is used to read and analyze the mammography image.
A film screen mammogram records black and white images in a large film sheet while in a digital mammogram captures image onto a computer screen. The benefit of these electronic images is that they can be enlarged on the screen and also they can be sent electronically from one location to another. Both the tests are known to be accurate and equally give reliable results. It has been studied that for women over 50 and also for women having denser breasts digital mammography gives good results. Also women starting with menopause give better results with digital mammography.
As discussed earlier digital mammography has two basic advantages over traditional film mammography. First being that in digital mammography as the images are electronic, they can be manipulated for better viewing and also they can be transmitted anywhere. Secondly the radiation exposure is much less than film screen mammograms. The only drawback this digital technique has is that it is less widely available and also a little expensive as compared to traditional film screen mammography.
It is best to get mammogram imaging done at an accredited facility as an accreditation ensures that the machinery, equipments and the medical team are affiliated to certain standards.
A patient can find out or enquire about the volumes of mammograms being conducted at the facility and the frequency of the same. They can also enquire about the analyzing of the report by the radiologist and the treating doctor. A patient can find out if the reports shall be shared immediately with her and would she be given a copy of the film and the report.
A routine mammogram would show calcifications, Cysts, Fibroadenomas.
In a regular mammogram, two views from opposite angles are taken. In a diagnostic mammogram, more views are covered and both bests are covered in both the types. This is to ensure that no abnormality is left out. In a mammogram following of the tissue structures may be isolated by the radiologist.
1. Calcifications: These denote dead cells. They appear like grains of salt on the mammogram image and are tiny flecks of calcium. They are signs of early breast cancer. Calcifications can be of two types: macrocalcifictions and microcalcifications. These cannot be felt as lumps or bulges but are easily detectable on a mammogram. Macro-calcifications or big calcifications usually do not mean cancerous growth. Clusters of micro calcifications are small calcifications in a group. These are primarily due to increased activity of cells. Predominantly these re non – cancerous in nature but they are a sign of early cancer. The doctor will want to conduct further tests on the tissue as per the initial findings of the calcifications – shape, size and number.
2. Cysts: Sometimes radiologist can also see fluid filled masses in the breast- these are called cysts. They are predominantly benign and are very common masses in the breast tissue. Though in rare cases, they can be associated with cancers. As a follow up, to evaluate if the cysts are cancerous in nature – ultrasound test can be done on the cyst. In an ultrasound test sound waves are passed through the mass. If the tissue has a lump, these waves are bounced back to the film detecting a cancerous cyst.
3. Fibroadenomas: These growths are very common in young women are not malignant in nature. These are made up of normal breast cells and are solid and round and movable. These lumps usually grow in size and if the lump is seen to be growing in size, it is surgically removed.
In a mammogram a radiologist may look for any of the following abnormality:
But every abnormality may or may not be cancer and as such it has to be followed by a subsequent test. A mammogram is first step in the breast cancer screening.
In certain cases the radiologist may take the help of CAD technique. In this the images are read and analyzed by a computer software program and highlights area of concern in the image. CAD helps isolates and focus on “suspected areas”. CAD is done on digital form of images so film- screen mammography image films are converted into digital images with the help of a special machine. The digital mammography images are used in the same form.
CAD has been known to at times identify cancerous growth masses which have been missed by radiologist. On the other hand at times they have been known to give “false positive” results – increasing the number of subsequent biopsies
Many radiologists world wide use the Breast Imaging Reporting and Database System, or BI-RADS for reporting the findings of mammograms. In it the findings are categorized from a scale of 0 to 6.
This mammogram testing which is done post breast cancer removal surgery is mostly for monitoring purposes. It is highly likely that a woman is put on periodical mammogram testing post lumpectomy, mastectomy or a breast implant surgery.
For women with a history of lumpectomy with a radiation therapy a usual mammogram screening is recommended after 6 months of finishing the therapy. Radiation therapy can result in some changes in the breast. a post 6 month mammography then becomes the “standard” mammography image for future mammogram images to be compared with.
Sometimes breast reconstruction is followed by lumpectomy, in such cases a baseline mammogram is ordered once the tissue is completely healed. After 6 months in most of the cases annual screening mammograms are sufficient to monitor breast cancer treatment response.
In mastectomy the entire breast with large cancerous growth is removed. Since in this procedure, the entire breast tissue is removed mammogram of that side are not required but the other breast is regularly screened by mammogram. As chances of developing cancer in the other breast are quite high if one breast has been detected and diagnosed with breast cancer.
In cases when double mastectomy – or removal of both the breasts has been done, no mammogram is required post mastectomy.
Another type of mastectomy called nipple sparing mastectomy in which the nipple and the tissue underneath is spared is also done. In such cases there is sufficient leftover braest tissue which may require mammograms. In such mastectomy cases also mammograms are done post surgery.
In breast reconstruction procedures implants are used. These may be saline or silicone implants. In this procedure the entire breast tissue is removed and due to the silicon, the surrounding tissue is not visible. In such cases no mammogram, testing is done post surgery. Though no mammogram is possible but a careful physical examination is feasible in such cases.
In a reconstruction in which tissue from other body part is used is called autologous reconstruction. In this also as the entire breast tissue is removed typically no mammogram is required. Unless the patient is at high risk for local recurrence, or the physical examination of the breast is difficult or there has been a finding of objectionable abnormality.
In a mammogram post a breast reconstruction surgery the possible findings are benign fat necrosis – which are dead fat cells. These may form a lump which may reduce in size over time.
For nipple sparing mastectomy when breast reconstruction is done, mammography is possible. Also apart from mammography in post surgical patients, Breast MRI may also be done on patients which are high risk cases.