Breast Cancer: One in Eight...
Women will develop breast cancer. But there is hope in detecting the disease
early with new Breast Imaging techniques. Cancer is the second leading cause of
death in the United States, and in women, breast cancer is the most common
cancer. Approximately 13 percent of women, or one in eight, will develop breast
cancer sometime in their lives.
Many of these cancers, if not treated, will spread through the lymph system or bloodstream to other sites in the body. However, if the breast cancer is discovered and treated early, before it has spread, the chances of a cure are very high - greater than 90 percent for small cancers that are contained within the breast tissue. Early detection is therefore critical for increasing the odds of breast cancer survival.
There is now general agreement that screening mammography can reduce the rate of death from breast cancer among women who are age 40 or older. Scientific studies have shown a decrease in mortality of 15-35% in women 50-69 years of age. Women between the ages of 40-49 have a smaller but significant decrease of 15-20%.
For traditional mammograms, the breast is compressed between a plastic plate and a cassette holding the X-ray film. X-rays passing through the breast expose the X-ray film creating a permanent image that can be viewed on a light box. A screening mammogram usually involves two views of each breast. Additional films may occasionally be obtained if necessary to image the entire breast or to evaluate breast implants. Although uncomfortable, the compression lasts only a few seconds, with the average screening mammogram lasting 15-20 minutes.
The major limitation of mammography is that breast cancer can be difficult or impossible to see in women who have "dense" breasts. Dense breasts contain large amounts of glandular and fibrous tissue (in contrast to women with breasts composed mainly of fatty tissue), which have a similar contrast appearance to breast cancers.
Full Field Digital Mammography
In the past five years, full field digital mammography (FFDM) has been developed, in part, to address this problem. Instead of exposing a sheet of X-ray film, digital mammography uses a special sensor to capture and convert the X-ray energy into an electrical signal. This digital information can then be processed and stored on a powerful computer system. Digital mammography separates image acquisition and image display, allowing optimization of both. Computerized post-processing of the digital data allows the image contrast to be manipulated and optimized for dense glandular breast and displays a more uniform image. Since the images are stored electronically, they can be transferred to distant sites for evaluation. The image is always available for review or for additional image processing, if needed.
In 2005, the results of a large scientific study comparing digital mammography and traditional film mammograms was published. Over 49,500 women from the U.S. and Canada had both types of mammograms on the same day. For certain groups of women in the study, expert radiologists were able to detect nearly 30% of cancers only on the digital mammograms - not on the film mammograms. Those who benefited from this technology included:
- Women with radiographically dense breasts
- Women under age 50
- Pre-menopausal or peri-menopausal women
In other words, digital mammography was better than film mammography for detection of cancer in more than half of the women that were in the study.
Cancer Imaging With Breast MRI
Digital mammography has become the standard of quality for breast cancer screening. Even with the best technology and skilled radiologists, mammography does not provide all the answers in the search for evaluation of breast cancer. Ultrasound and Magnetic Resonance Imaging (MRI) are also important tools in the fight against breast cancer. Although MRI of the breast was first performed twenty years ago, it has only been in the past few years that the equipment and computer power have reached the level of sophistication needed to create highly detailed images.
MRI is used to obtain more information when an abnormality is suspected on physical exam or mammography, but cannot be seen clearly enough with mammograms or breast ultrasound. MRI can often overcome conditions that limit the accuracy of mammography such as previous breast surgery (especially lumpectomy for breast cancer), radiation treatment, and traumatic breast injuries. If breast cancer is suspected, radiologists with special training in breast imaging can determine the fastest and easiest way to obtain a biopsy for diagnosis. Certain genetically at-risk individuals (carriers of the BRCA-1 or BRCA-2 genes) may even benefit from screening breast MRI in addition to genetic counseling and yearly mammograms. MRI is not usually beneficial for problems such as generalized pain, swelling and tenderness in the breasts.
Bringing It All Together
The radiologists of Diagnostic Radiology Consultants (DRC) have interpreted over 15,000 digital mammograms since introducing full field digital mammography to the Chattanooga area in 2004. DRC now offers this same standard of quality as well as walk-in convenience at Tennessee Imaging and Vein Center on Gunbarrel Road. Our doctors are committed to an integrated, judicious, and caring approach to the diagnosis of breast cancer. Digital mammography is the foundation. Breast ultrasound and MRI are available for more advanced imaging, if necessary. DRC is also the only medical practice in the region that performs minimally-invasive needle biopsies of the breast utilizing digital mammography, ultrasound or MRI for guidance.
Lawrence J. Samuels, M.D., "One in Eight...," The Chattanooga Times Free Press, Healthwatch, January 2007, 32-33.