Pisano et al (2005) studied the “diagnostic performance of digital versus film mammography for breast cancer screening.” About 40,000 women participated in the trial; each subject was screened by both methods.

“[The trial] did not measure mortality endpoints. The assumption inherent in the design of the trial is that screening mammography reduces the rate of death from breast cancer and that if digital mammography detects cancers at a rate that equals or exceeds that of film mammography, its use in screening is likely to reduce the risk of death by as much as or more than ... film mammography.”
There was little difference in cancer detection rates for all women. However, for women with radiographically dense breasts (about half the subjects and many of the cancers), the detection rate was about 25% higher with digital mammography. This difference is highly significant.

(a) Granting the authors’ design assumption, would you recommend digital or film mammography for women with radiographically dense breasts? for other women?

(b) What do you think of the design assumption?