Cancer Institute to Study Digital Mammography
early March, Carl D'Orsi, MD, director of Oncologic Imaging at Emory
University's Winship Cancer Institute (WCI), will participate in one
of the largest mammography studies ever conducted in the United States.
The study, which is being
conducted at WCI and 19 other institutions around the country, will
compare digital with standard, or analog mammography. Funded by the
American College of Radiology Investigative Network through a project
grant from National Cancer Institute, the new study will compare digital
and standard mammograms on 45,000 women over the course of 18 months.
Each of the 20 sites will work with approximately 2,000 women using
both digital and standard mammography units in order to compare images.
"The purpose of the study,"
says Dr. D'Orsi, "is to determine whether digital mammography is equal
to, better, or worse than standard mammography. In addition, we will
attempt to determine if a particular digital unit provides better results
than other units." There are currently four digital mammography manufacturers:
General Electric, Fisher, LoRad, and Fuji. The system that will be in
place at WCI is a GE digital mammography machine.
Dr. D'Orsi conducted a similar
study on a smaller scale 3 years ago at the University of Massachusetts
Medical Center in Worcester, Massachusetts, where he was professor and
vice chairman of the Department of Radiology. In that study, Dr. D'Orsi
collaborated with investigators at the University of Colorado. Both
sites worked with approximately 2,000 women. Results from the study
indicated there was no significant difference between digital and standard
mammograms. That study is being used as the basis for the current study.
The Federal Food and Drug
Administration first approved digital mammography in January 2000. Film/screen
mammography along with physical examination and breast self-examination
remains the standard method for breast cancer screening in women. Digital
technology, however, offers several potential advantages over the standard
use of radiographic film. Unlike images on radiographic film, digital
- Can be stored and transferred electronically, which facilitates their
quick and easy retrieval as well as remote evaluation by distant specialists;
- Can be manipulated to potentially enhance cancer detection without
the necessity of taking another mammogram;
- Have a large dynamic range that allows examination of all areas of
the breast, despite their varying density. The limited dynamic range
of film/screen systems sometimes requires additional exposures to examine
very high or very low density areas of the breast.
"Part of what we are working
on here is a reduction in the number of‘recalls' we have," says Dr.
D'Orsi. "We often see something on radiographic film that we can't clearly
define, and we have to call the patient back in to have another look.
This is time consuming, causes obvious anxiety and is expensive. If
digital mammography can help us reduce unnecessary recalls, then everyone
benefits, and we are taking a step in the right direction with this