Study designs of evaluations included in the review
Randomised controlled trials (RCTs) were eligible for inclusion in the review.
Specific interventions included in the review
Studies of population-based mammography were eligible for inclusion in the review. Studies of opportunistic screening and case-finding were excluded. The reported rounds of mammography in the included studies ranged from 2 to 6.
Reference standard test against which the new test was compared
The review did not include any diagnostic accuracy studies that compared the performance of the index test with a reference standard of diagnosis.
Participants included in the review
Studies of women older than 50 years were eligible for inclusion in the review. Primarily symptomatic patients with breast lumps, pain, nipple discharge, or enlarged lymph nodes were excluded. The majority of women in the included studies were white. The results of the review were subsequently applied to data from Hong Kong (where 95% of the population were Chinese) and extrapolated to other Asian populations.
Outcomes assessed in the review
Studies measuring breast cancer-related mortality (with a minimum follow-up of 5 years and 10 breast cancer deaths) were eligible for inclusion. The duration of follow-up in the included studies ranged from 11 to 18 years. In the context of Asian populations, the number-needed-to-screen (NNS) to prevent one death or adverse event was also assessed.
How were decisions on the relevance of primary studies made?
Two reviewers independently assessed the studies for eligibility for inclusion in the review.