Repeated screening for breast cancer.

In a screening service for breast cancer the results of routine repeat tests of women will contribute more than the results of their initial tests. A comparison of first and subsequent screens in a group of high risk women suggests that the sensitivity of screening declines between first and subsequent visits, whereas its specificity improves. Despite improved specificity, the ratio of benign biopsies to cancer was worse at repeated screening (21 to 1) than at first screening (6 to 1). This was because between first and subsequent screens the yield of cancers fell to a greater extent than the yield of benign disease. The patients with breast cancer diagnosed during this study were remarkable for their good prognosis, 92% being still alive and 86% free from recurrence at their last follow up, the follow up intervals ranging from four to eight years.