New Imaging Technique Spots Hidden Breast Tumors
It could benefit women at elevated risk of cancer
WEDNESDAY, Oct. 1, 2003 (HealthDayNews) -- Finding breast tumors at their earliest, most easily treated stage is one step closer to reality, thanks to new research conducted at the University of Colorado Health Sciences Center.
In a study in the October issue of Radiology, the researchers show how adding a contrast dye to digital mammography can reveal tumors not otherwise visible with conventional screening, particularly in certain high-risk women.
"We expect [this method] will become an alternative to breast magnetic resonance imaging (MRI) in evaluating difficult-to-interpret mammograms or for screening women who have an elevated risk for breast cancer," reports study author Dr. John Lewin. He is an associate professor of radiology at the health sciences center and director of breast imaging research and co-director of breast imaging at the University of Colorado Hospital Breast Center in Aurora.
The new technique may also be useful for identifying potentially malignant breast abnormalities in women who have already been diagnosed with one breast cancer, Lewin says in a statement.
Current studies show conventional mammography, which uses X-ray film to image the breast, miss up to 20 percent of all breast cancers, including nine percent where a lump in the breast can be felt.
The new technique -- called dual-energy contrast-enhanced digital subtraction mammography -- is filmless. Instead, it uses two ultra sharp computerized or "digital" images of the breast. One image is taken much like a regular mammogram, but displayed as a digital picture on a computer screen. The second image is taken in conjunction with a contrast dye that tries to "light up" areas of new blood vessel growth commonly associated with tumor development.
The two images are laid on top of one another and the matching areas of both are subtracted or removed. What's left is very often the image of a tumor -- one that might otherwise be too small or too hidden within dense breast tissue to be seen, the researchers say.
For breast imaging specialist Dr. Michael Cohen, the technique -- and the new study -- represent a step toward the future of diagnosing breast cancer, particularly in women who may be at very high risk.
"This is good science, and we need pioneers like Dr. Lewin to push the envelope and that's what he's doing. He's taking a modality and applying some things we have done in the past, he's updated them, and he's laying the groundwork for what may be an exciting diagnostic option for certain women in the future," says Cohen, director of the Memorial Sloan-Kettering Guttman Diagnostic Center in New York City.
The new research is classified as a "feasibility" study, says Cohen, meaning it is a scientific look at whether future research is warranted in this area.
"The paper concludes that it is warranted, and I would definitely agree with that," Cohen says.
The small but important study involved 26 women whose traditional mammograms or breast exams found lumps or other abnormalities, indicating the need for a biopsy, but without verification of a malignancy.
All 26 received the new dual, contrast-enhanced digital subtraction mammogram. Of this group, 14 of the women were ultimately shown to have cancer. Eleven of those cancers appeared as "strongly enhanced" images on the new high contrast mammogram, one appeared moderately enhanced, and two more were weakly enhanced.
For the 12 women who were ultimately found to be cancer-free, the new mammogram showed either weak enhancement or no enhancement at all.
Ultimately, Lewin says, the contrast dye mammograms "lit up" every malignancy and let doctors see tumors that were virtually invisible on traditional mammograms.
Currently, there is no commercial machine available to perform this type of mammogram, and Lewin admits in the study he has not yet determined the precise level of radiation needed to obtain the clearest pictures.
And Cohen adds that even if the system should become commercially available, it would not be necessary for all women.
"However, for those who could benefit -- someone with dense breasts for example, or when we can feel a lump, but it does not appear on a traditional mammogram -- this could one day be an excellent diagnostic tool that is fast and easy and may yield important, even lifesaving answers," Cohen says.
Currently, the University of Colorado Health Sciences Center, the University of California at San Francisco, and Brigham and Women's Hospital in Boston are planning a joint clinical trial to study this new form of mammography, to determine which women it might help most. The trial is set to begin in October 2004.
In the meantime, high contrast magnetic resonance imaging is available, though costly, as well as digital mammography without the use of contrast dye.