Digital mammography for cancer detection

As a screening measure for breast cancer, digital mammography is more accurate than conventional mammography at detecting the disease in women with dense breasts, women younger than 50 years of age and premenopausal women. Conventional mammography involves the creation of a breast image directly onto film. With digital mammography an electronic image is taken and stored in a computer. The display characteristics of the image can then be manipulated and the radiologist can use software to help detect breast abnormalities. Previous reports have shown that conventional mammography is limited in its ability to detect cancer in dense breasts, which are commonly found in younger women. Still, despite the apparent advantages of digital mammography, previous studies have failed to show that it is more accurate than conventional mammography. However, these studies only used one type of digital detector and did not have enough study participants to detect small differences in accuracy. Researchers from the University of North Carolina, Chapel Hill, USA, did a Digital Mammographic Imaging Screening Trial (DMIST) wherein 49,528 women with no signs or symptoms of breast cancer were screened for the disease with both digital and conventional mammography. Two radiologists interpreted the mammograms. Breast cancer status was determined through biopsy. The study compared film mammograms to digital mammograms. In the overall analysis, digital and film mammography were similar in their ability to identify breast cancer. However, digital mammography was significantly more accurate than the usual film mammography at detecting cancer in women younger than 50 years of age, women with dense breasts and premenopausal women. While these findings are encouraging, the adoption of digital mammography as a routine screening measure depends on another factor - cost. Digital systems currently cost approximately 1.5 to 4 times as much as conventional systems.