Frequently Asked Questions - Mammography

1. What is mammography?
2. How is a screening mammography different from a diagnostic one?
3. What is the objective and what is the value of the screening mammography?
4. What are the disadvantages and negative effects of screening mammography?
5. What is analog (film) and what is digital mammography? Which is best?
6. Can we replace mammography with ultrasonography?
7. Do the mammography and ultrasonography be taken on a specific day of the (menstrual) cycle?
8. What is 3D mammography or tomosynthesis?
9. What is a magnetic resonance mammography (MRM) and when should it be done?
10. What is the BI-RADS system in breast imaging?
 
1. What is mammography?

Mammography is a radiology examination that uses low-energy X-rays to examine the breasts. Basically, it uses low-dose ionizing radiation to generate images of the breasts, which will later be evaluated by specialized physicians. It is the basic imaging test for both diagnosis of symptomatic women (e.g. women with palpable masses) and screening of healthy women. In the first case we refer to a diagnostic mammography and in the second to a screening mammography.

 
2. How is a screening mammography different from a diagnostic one?

Screening mammography involve taking of four views, two for each breast (face and profile). Diagnostic mammographies might require more views, e.g. from a different angle or magnification views/spot compression views, to examine the breast in more detail.

 
3. What is the objective and what is the value of the screening mammography?

Screening mammography aim at diagnosing breast cancer at a very early stage so that it is treated successfully and its prognosis is very good. The disease is considered to be at an early stage when it is locally limited to the breast and has not spread to the rest of the body. Clinical trials have shown that screening mammography has reduced the rate of deaths caused by breast cancer at the ages of 40 to 70 and especially at the ages over 50. The value of screening mammography for women under 40, with the exception of high-risk women, such as BRCA mutations carriers, has not been established. The basic or reference mammography which should be done at the age of 35-40 also has no established value as far as the reduction of deaths caused by breast cancer is concerned.

 
4. What are the disadvantages and negative effects of screening mammography?
Like all examinations, screening mammographies have disadvantages and possible negative effects.
 
  • The early diagnosis of cancer unfortunately does not always mean that the woman will not die of breast cancer. In some cases, the rapid growth and aggressive nature of the tumor have already led to its spreading, even if the tumor is a very small one and is only apparent in the mammography. In these case, the woman will not benefit from screening mammography and she will also experience the nervousness and stress linked to the disease for an additional period of time (the period when she would feel healthy and would not know about the existence of the cancer).
     
  • False negative results. False negative result is a case where the mammography appears normal while there is malignancy in the breast. All in all, a screening mammography might miss 15-20% of the cancers existing at the time of examination.  The most common reason for this is the increased density of the breasts. This means that false negative results are most frequent in younger women, whose breast tissue -as a rule- is denser. In older women, because of breast involution ( dense fibroadenomatous components have been replaced by fat), false negative results are rarer.
     
  • False positive results. False positive result is a case where the mammography is assessed as pathological while there is no malignancy in the breast. Each mammography with a pathologic finding is followed by a series of tests (additional views, ultrasonography, biopsy) to see if there is cancer or not. False positive results are more frequent in younger women, women with history of breast biopsy, with family history of breast or ovarian cancer or with history of estrogen administration. In these cases, women undergo stress, physical and psychological distress and economic loss for something that is not cancer.
     
  • Overdiagnosis and overtreatment. We know that a lot of cases of Ductal Carcinoma in situ as well as some slowly growing infiltrating cancers, especially in older women, would never present with symptoms and would never threaten the woman's life. These cases are diagnosed with screening mammography and lead to cancer "overdiagnosis". Moreover, since there are no clear criteria to set "innocent" cancers apart, all of these cases are treated. This way we are led to "overtreatment".
     
  • Exposure to radiation. Mammography requires a very low dose of radiation. The risk of damage due to this radiation is extremely low; however, repeated exposure creates a theoretical risk for the development of malignancy. The advantages of screening mammography almost always outweigh the theoretical risk from exposure to radiation.
 
 
5. What is analog (film) and what is digital mammography? Which is best?

Both the analog and the digital mammography use ionizing radiation (X-rays) to create an image of the breast. In analog (film) mammography this image is directly captured on a special film whereas in digital mammography a digital image is created and saved in the form of an electronic file. The digital image can be magnified and processed for further use much more easily than the film. The capability of saving, editing, easily retrieving and sharing of the electronic file makes digital mammography more preferable for the following reasons:

  • Doctors can electronically share the images and have a virtual conference with other radiologists or breast surgeons many miles away
     
  • Vague differences between normal and pathological tissues are more easily discerned
     
  • Fewer repeat takes are possibly required, reducing exposure to radiation
     
  • Fewer repeat tests are possibly required

Although studies carried out have not shown that digital mammography is better than the analog in reducing deaths caused by breast cancer, it appears that digital mammography is more sensitive and precise than the analog mammography in younger women with dense breasts.

 
6. Can we replace mammography with ultrasonography?

No. Ultrasonography is a very useful examination for the imaging of the breast both as a diagnostic and as a screening process but it cannot replace mammography. It is a supplementary examination for cases where the mammography has produced a finding or for women with dense breasts, in which cases the mammography is not very sensitive. The ultrasonography is used as a basic method to examine young women. In this case, the possibility of growing a tumor is low and the sensitivity of the mammography very low due to the high density of the breasts.

 
7. Do the mammography and ultrasonography be taken on a specific day of the (menstrual) cycle?

No. Imaging tests are equally valuable irrespective of the day of the woman's cycle. Benign and malignant lesions are imaged in the same way both before and after menstruation.

The only case when mammography is preferably performed during the 7th-12th day of the cycle is when the woman has intense cyclical mastalgia, i.e. intense swelling and pain in the breasts right before and during menstruation. In these cases, we avoid performing a mammography on these specific days, because the test becomes unpleasant and painful to the woman. In addition, we advise the woman to take a common painkiller before the test, so that the unpleasantness and pain are reduced.

 
8. What is 3D mammography or tomosynthesis?

The 3D mammography or tomosynthesis is a type of digital mammography. Images of thin sections of the breast are taken using X-rays and from different angles and then, by means of a special software the image of the breast is reconstructed. This process is similar to the process of taking images of the body in CT scans. Tomosynthesis uses very low radiation; however, since it is always carried out in conjunction with four mammography views, the final dose of radiation might be higher. There are no major studies comparing the accuracy and sensitivity of the tomosynthesis with those of the mammography. Today, it does not constitute a screening method but in some cases it can complement the mammography and offer more information, especially in women with dense breast.

 
9. What is a magnetic resonance mammography (MRM) and when should it be done?

The magnetic resonance mammography is a radiology method of breast imaging. It uses high magnetic fields and achieves high-resolution imaging of the breast structures. The magnetic resonance mammography is a dynamic test in the sense that, in addition to imaging the breasts morphologically, it also studies the behavior of the different structures after administration of a special contrast agent (the paramagnetic agent gadolinium). It is very highly sensitive in the imaging of malignant lesions but it has low specificity. This means that it has a high rate of false positive results in healthy women, i.e. it detects "cancers" which are not really there. Moreover, the test has a very low sensitivity in detecting low-grade ductal carcinomas in situ, unlike the mammography, the sensitivity of which is higher.

The main indications of magnetic resonance mammography are:

  • Testing of a patient with diagnosed cancer for possible multicentric disease (more than one foci in the same breast)    
     
  • Testing of a pregnant woman with suspicious lesion in the breast
     
  • Testing of a patient who has undergone mastectomy for breast cancer and reconstruction with musculocutaneous flap
     
  • Testing of a patient with breast cancer who is undergoing pre-operative chemotherapy, in order to assess the response to therapy and plan surgical treatment, especially if it is partial mastectomy.
     
  • Screening of women with a genetic mutation (BRCA1, BRCA2)

Screening women with very dense breasts using a magnetic resonance mammography is a controversial issue, especially due to the low specificity of the examination method. Another problem in this case is the performance of magnetic resonance mammography-guided biopsy. This procedure is not wide-spread because it is time-consuming and expensive. This means that it is impossible to manage a lesion which is detected through a MRM but is not visible in the mammography or the ultrasonography. A center that offers screening using MRM should normally have an MRM-guided biopsy system or at least a pre-operative hook wire localization system. Otherwise, MRM provides information which cannot be used.

 
10. What is the BI-RADS system in breast imaging?

The American College of Radiologists (ACR) has established a system for describing and classifying imaging findings in the breast, so that the communication between medical specialties involved is facilitated and that these findings are managed in a clear way. This system is called BI-RADS (Breast Imaging Reporting and Database System).

 
 
 
 
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