"Adding computeraided detection to mammograms finds more early noninvasive cancers and helps detect invasive cancers at earlier stages according to a large new study. But the jurys still out as to how worthwhile the extra technology is overall.  For one thing computeraided detection CAD increases the amount of diagnostic testing among women who turn out not to have breast cancer. And the technology makes mammograms more expensive.  CAD is becoming more widespread said Dr. Joshua Fenton an associate professor of family and community medicine at the University of California Davis and lead study author. Its an addon and now is used in probably threequarters of U.S. mammograms he said. Computeraided detection systems use a digitized mammogram image from either a traditional film mammogram or a digitally acquired mammogram according to the American College of Radiology. The CAD software looks for areas that may indicate cancer so the radiologist can then look more closely at the mammogram. Although it has rapidly become part of mammogram screening Fenton said there is limited and conflicting research on its effect. Under Medicare payment rates doctors get an additional  for adding computeraided detection to a mammogram said Fenton citing Medicare data. The Medicare rate for a film mammogram is  while a digital mammogram is . His team evaluated more than  mammograms  with and without computeraided detection  from more than  women aged  to . The study is published in the April  issue of the Annals of Internal Medicine. Fenton took data from a large U.S. epidemiology database from  to . During that time computeraided detection use increased from . percent to . percent. Now with about  percent of mammograms adding it it is even more common Fenton said. In our study we assessed its impact in the Medicare program he said. The researchers compared the results when mammograms included CAD to when they did not. When computeraided detection was used doctors found a greater number of early cancers known as ductal carcinoma in situ or DCIS. But the overall rate of invasive breast cancer diagnosis was no different with or without CAD Fenton said. However among the women who did have invasive cancer computeraided detection was linked with a greater likelihood of finding the cancer while it was stage  or  compared to stage  or  they found. CAD was also associated with increased diagnostic testing among women who turned out not to have breast cancer he said. These women because breast cancer was suspected had to be called back for additional tests such as repeat mammograms or biopsies. So is the new computer technology worth it Our study doesnt answer that question it raises that question Fenton said. The findings he said are a mix of potential good news and not so good. The additional tests that turn out to be unnecessary because no cancer is found are not desirable he said. Some of the very early cancers diagnosed in older women he noted may not have caused them a problem during their lifetime. But doctors cant say with certainty which ones will progress and which ones will not. Women should recognize that CAD comes with some potential risks Fenton said. It has the potential risk of a falsepositive mammogram. If you are an older woman there is the risk of overtreatment of noninvasive lesions. Dr. Daniel Kopans a professor of radiology at Harvard Medical School and senior radiologist in the breast imaging division at Massachusetts General Hospital said the study provides additional information to doctors and women but has some limitations. He was not involved with the study. The good news is the use of CAD was related to finding invasive cancers at smaller sizes and earlier stages than before the CAD era said Kopans also a member of the American College of Radiologys Breast Imaging Commission. There should be no argument that finding invasive cancers at a smaller size and earlier stage is beneficial he said as they are more likely to be cured.  While he calls finding more DCIS with computeraided detection also likely a good thing he acknowledged the debate about the possibility that a very early cancer in an elderly woman may not cause a problem in her lifetime. Although the treatment of DCIS is debated among experts Kopans said In my mind it is always worth it to find additional cancers. One limitation of the study he said is that the researchers cannot say for sure it was the computeraided detection that made the difference. Other factors could have played a role such as the radiologists becoming more experienced he said. More information To learn more about mammography http visit the American College of RadiologyRadiological Society of North America. SOURCES Joshua Fenton M.D. M.P.H. associate professor of family and community medicine University of California Davis Daniel Kopans M.D. professor of radiology Harvard Medical School senior radiologist breast imaging division Massachusetts General Hospital and member American College of Radiology Breast Imaging Commission April   Annals of Internal Medicine"