Press Release: Study Examines Reasons for Late-Stage Breast Cancers

Extract

Efforts focused on increasing the use of screening mammography among targeted groups of women should be made a top priority to achieve the largest reduction in late-stage breast cancers, according to the authors of a new study in the October 20 issue of the Journal of the National Cancer Institute. However, the author of an editorial in the same issue suggests that certain biases often found in breast cancer screening studies should be taken into account when interpreting the results of the study.

Because mammography increases the detection rate of early-stage breast cancers, the incidence of late-stage breast cancers should decline. However, despite high levels of screening in the general population, late-stage breast cancers still occur. The occurrence of late-stage breast cancers could indicate failures in the screening process.

To establish where the screening process breaks down and where changes in care might have the greatest impact, Stephen H. Taplin, M.D., M.P.H., now at the National Cancer Institute, and colleagues in a consortium of integrated health plans, The Cancer Research Network, conducted a retrospective case–control study using data from seven health care plans that included 1.5 million women aged 50 years and older who had access to screening mammography. They compared women who had been diagnosed with late-stage breast cancer with those who had been diagnosed with early-stage breast cancer and, on the basis of their earliest screening mammogram during the period reviewed, categorized the women into one of three groups: absence of screening, absence of detection, or potential breakdown in follow-up.