03 Oct Breast Cancer: DMIST Trial
Another large topic specific to Breast Cancer is the use of digital mammography and its benefits versus the use of traditional film based mammography. There was a trial that was created in 2003 by the National Cancer Institute (NCI) called the Digital Mammographic Imaging Screening Trial, or better known or referred to as the DMIST Trial. This trial reached its enrollment target goal of 49,500 women in the U.S. and Canada. The trial is officially closed as researchers finalize and analyze all of the data that was collected.
The purpose of the Study?
The purpose of the study was to examine if digital mammography was as good as, or even better, then conventional film-based mammography. The study enrolled 49,500 women across the U.S. and Canada and all women were then given a digital mammogram and a film-based mammogram. The mammograms were then reviewed by two separate and independent radiologists specializing in Breast Mammography. Breast Cancer status was determined through available breast biopsy information obtained within 15 months of enrollment onto the study or through follow-up mammography exactly one year later.
Digital mammography takes an image of the breast and then stores it on a computer. This image is then viewed by radiologists specializing in Breast Mammography. These images can then be manipulated on the computer to allow for enhancement of the images, zoom in and out, darkened or lightened, and for the image to be rotated into other views or angles. The digital images can also be printed onto film. Traditional film-based mammograms can only be printed once, and only onto film. This feature is nice since it means less time for the patient to wait and see if the images are a good quality since there is no developing time required. It also means a decreased number in repeat mammograms since the images can be enhanced electronically. This ultimately leads to less radiation exposure to the patients.
Here is an example: This is a mammogram taken in the same view angle of the same breast. The image on the left side is a digital mammogram. The image on the right side is a traditional film-based mammogram. As you can tell the image on the left side, the digital mammogram is clearer and much sharper then the image in the right side. If there happened to be small areas that might be questionable, the image on the left hand side can be magnified onto those areas and looked at more closely. If the same thing happened on the right side, another mammogram would have to be taken to magnify that area in question. This means another exposure for a film, waiting to process it to make sure it is good quality, and what women typically dislike the most, another compression of the breast.
What is a digital mammogram like?
Unfortunately a digital mammogram is almost identical in experience to a traditional mammogram. There is still the compression of the breast as well as the positioning of the breast onto the screen of the machine. The machine might look slightly smaller and more compact, but other then that, there are no viewable differences between the two mammogram techniques.
On September 16, 2005 the American Collegeof Radiology Imaging Network released, in a special edition of the New England Journal of Medicine released on-line, the first results of the DMIST trial.
What the study found was the following:
There is NO significant difference between traditional film based mammography and the newer digital mammography in the general population of women.
In women 50 years of age and younger, premenopausal and perimenopausal women, and women with dense breasts, digital mammography DOES detect significantly more Breast Cancers. (referred to from this point on as sub-group)
In this particular sub-group of women, there was a 28% increase in the detection of breast cancers with digital mammography.
Of all the participants in the DMIST trial, 65% of the women participating, fit into at least one of the above mentioned subgroups.
Breast cancer is the most common non-skin cancer, and the second leading cause of cancer-related death in women in the United States. Death rates from breast cancer have been declining since the 1990’s. The decreases are believed to be the result, in part, of earlier detection, better screening programs, and improved treatment options for women with breast cancer.
The DMIST trial was performed to measure relatively small, but potentially clinically significant, difference in accuracy between digital mammography and film based mammograms. While any differences that were detected might be relatively small, they could improve breast cancer detection for all or some small groups of women. This DMIST trial did in fact show that for women in the U.S.ages 50 years old and younger, women that are premenopausal or perimenopausal, and women with dense breast tissue that there is almost a 30% increase in the detection of breast cancers with digital mammography. It also showed that there could be as many as 50% of the screening population that would qualify into at least one of these groups of women.
At present, only 8% of all mammography units in the U.S.are digital. As technology advances, prices on new digital mammography units drop, more vendors make digital units, and as hospitals begin to adopt and then have to compete with other hospitals, digital mammography units will become more accessible for women. Another key factor in this adoption of digital mammography is that women and their physician need to become aware of what the DMIST trial is, what the results were, and if they happen to fall into one of the three categories of women that receive a benefit from digital mammography.
As always, if you or a loved one has any further questions, comments, concerns, or if you have any other questions relating to another cancer topic, please feel free to contact me at: CANCERGEEK@GMAIL.COM or CANCERGEEK@CANCERGEEK.COM.
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