Digital Mammography

Most important Action: Get Your Mammogram

Most important question: WHO is reading the Mammogram?

Breast cancer is a curable disease with greater than 95% survival if diagnosed in its earliest forms. Therefore, it is critical to diagnose breast cancer as early as possible in order for women to achieve the goal of a cure. Mammography , physical examination by a health care provider, and breast self examination, remain the mainstay of breast cancer screening. All three components are important.

Mammography is an x-ray examination that evaluates the breast. It uses the smallest amount of radiation, less than that obtained when flying transcontinentally. It is a well-accepted and effective method of diagnosing early stage breast cancer. Numerous studies have shown the UNEQUIVOCAL and large effect of improved survival in women who get mammograms, especially if they obtain routine examinations every year. It is the change in mammography that allows the radiologist to diagnose the earliest of breast cancer.

There are 2 different methods of obtaining a mammogram: Analog and Digital. Analog mammography has been widely available since the 1970's and is a tried and true method of effectively imaging the breast. It is obtained using film, which is developed and then interpreted by a radiologist. Digital mammography is acquired on a "detector." The data is then displayed on a computer screen. The difference is much like the difference between a picture taken with a film or analog camera and the now widely used digital cameras. With digitally acquired images, whether they be your family photos or your mammogram, there is the ability to "adjust" the image. Just as you can change the contrast or remove red-eye on your photos, so too, the radiologist can adjust the mammogram which is acquired digitally to improve the image.

Digital mammography has been available for over 5 years. There has been an enormous amount of interest in digital mammography by both patients and medical professionals. After its initial introduction, there were a number of studies which evaluated that critical question that everyone was asking, "Was digital mammography better at diagnosing breast cancer than analog mammography?" All initial studies comparing digital to analog mammography showed NO difference in cancer diagnosis. These studies did demonstrate that most cancers were seen by both technologies, but that there were some cancers that were seen only with analog and some only seen with digital. Overall, there was no difference in the ability to detect breast cancer with either technology. However, all prior studies were relatively small and only from one institution.

It became clear that a larger study, involving a number of institutions was necessary in order to definitely answer the important question of whether digital mammography was better. Therefore, the definite study was undertaken involving nearly 49,000 women from a number of institutions. The study looked at digital and analog mammograms taken of the same women at the same time. The study, which was recently published and covered in the media, showed that overall, there was no difference in the ability of analog or digital mammography to detect breast cancer. That is, the percentage of cancers diagnosed with both technologies was statistically the same. However, in a number of subsets of patients, digital mammography did fare better in diagnosing breast cancer. These groups include pre-menopausal women, women with dense breasts and women under 55. In these groups there was a small, but statistically significant advantage for digital mammography. Interestingly, 65% of the women in the study were in one of these 3 groups in which digital mammography was better.

It may seem dichotomous that overall there is no statistically significant difference between digital and analog mammography in a study where 65% of the women included had an advantage with digital mammography. This has to do with the percentage of women of various age groups which were included as well as the statistics used in this study. However, the message is that in many women it does not make a difference if you obtain your mammograms with an analog unit or a digital unit. What does matter is that YOU GET YOUR MAMMOGRAM!! However, if you are under 55, pre-menopausal or have dense breasts, you might want to consider having your mammogram with a digital unit.

It is important to understand that there are other considerations, besides the type of mammography machine that will impact the ability to detect breast cancer on your mammogram. It has been shown repeatedly and without question that WHO interprets your mammogram is critical!!! It is best to have your mammogram interpreted by a radiologist that concentrates on mammography (that is spends a majority of their time interpreting breast imaging studies) or even more, a radiologist who is a dedicated breast imager and devotes all their professional time to diagnosing breast cancer. If you are going to ask what type of machine your mammogram is being taken on, you should also inquire who is going to interpret your exam and what percentage of their time is spent in breast imaging. Although there have not been studies investigating which is more important, the type of machine or who is interpreting your examination, I believe the physician interpreting your study is more important. You might also want to find out if your mammogram is being assessed with computer aided detection (CAD) which uses artificial intelligence to improve breast cancer diagnosis by about 23%.

In summary, there are many factors which impact the ability to detect breast cancer on a mammogram. The recently reported study demonstrates that in some women, having their mammogram with a digital mammography unit will improve the diagnosis of cancer as will the qualifications and ability of the radiologist interpreting the examination and whether computer aided detection is used. However, it is important to remember that the most important factor is getting your mammogram. It is clear that if you don't get your mammogram, you will undoubtedly lose the potential opportunity to diagnose an early and curable breast cancer.