Premenopausal women appear to be more sensitive at detecting breast cancer when done during the first week of the menstrual cycle (day 1 of the menses to day 7) in women with a history of screening mammograms. Researchers analyzed 387,218 screening mammograms in premenopausal women that were associated with 1,283 breast cancers. Greater sensitivity was found in week 1 (79.5%) compared to week 2 (70.3%), week 3 (67.4%) or week 4 (73%). Oddly, in the small percentage of women who were getting a screening mammogram for the first time, the sensitivity was lower during week 1 (72.1%) than in week 2 (80.4%), week 3 (84.6%) and week 4 (93.8%).
Comments: Premenopausal women do tend to have denser breasts than postmenopausal women, due to more estrogen in their system. This is known to make it more difficult for mammography to detect small tumors. The results of this study, at least in the women with a history of screening mammograms, makes sense as the breast density may be less in the first part of the menstrual cycle when estrogen is the lowest.
Reference: Miglioretti D, Walker R, WEaber D, et al. Accuracy of screening mammography varies by week of menstrual cycle. Radiology 2011; 258(2):372-379.
In another study, from Spain, digital mammography results were compared with traditional screen film mammography and investigators found a lower false-positive rate in the digital mammography. After reviewing 242,838 mammograms (171,191 screen-film mammograms and 71,647 digital mammograms) from 103,613 women ages 45 to 69. The screen film mammograms had a 32% higher false-positive rate than the digital mammography. This was a false-positive rate of 7.6% in screen films and 5.7% in digital, although there was no significant difference in the overall cancer detection rate between the two groups.
Comments: The results of this study are not surprising. Digital mammography has been an important step in the evolution of mammography. It has been shown to be superior in contrast of normal vs. abnormal tissue with increased diagnostic quality of images, increased sensitivity particularly in dense breasts and a better ability to store images and transmit images electronically.
Reference : Sala M, Salas D, Belvis F, et al. Reduction in false-positive results after introduction of digital mammography analysis from four population-based breast cancer screening programs in Spain. Radiology. 2011;258(2):388-395.
