Mammography is most accurate in week 1 of cycle and in digital form

May 1, 2011

Among premenopausal women who have undergone mammography in the previous 2 years, mammography is more sensitive at detecting breast cancer when performed during the first week of the menstrual cycle than during the second, third or fourth.

Among premenopausal women who have undergone mammography in the previous 2 years, mammography is more sensitive at detecting breast cancer when performed during the first week of the menstrual cycle than during the second, third, or fourth week, according to a recent study from Seattle. A separate investigation from Spain shows that digital mammography has a lower false-positive rate than traditional screen film mammography.

In the first study, researchers analyzed 387,218 screening mammograms linked to 1,283 breast cancers in premenopausal women. Although overall they found little difference in mammography performance according to the week of menstrual cycle, they found greater sensitivity in week 1 (79.5%) in the 66.6% of women who underwent regular screening mammography than in week 2 (70.3%), week 3 (67.4%), or week 4 (73.0%). However, in the 17.8% of women who underwent mammography for the first time in this study, researchers found that the sensitivity was lower during the follicular phase (week 1, 72.1%; week 2, 80.4%; week 3, 84.6%; week 4, 93.8%; P=.051).

In the second study, researchers reviewed a total of 242,838 mammograms (171,191 screen-film mammograms and 71,647 digital mammograms) from 103,613 women 45 to 69 years of age. The false-positive rate was about 32% higher for screen film than for digital mammography (7.6% and 5.7%, respectively; P<.001). The difference was particularly evident when mammography was performed after an invasive procedure (1.9% and 0.7%, respectively; P<.001). Researchers observed no significant differences in the overall cancer detection rate between the 2 groups (0.45% and 0.43% in the screen film and digital mammography groups, respectively; P=.59).

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.