Screening for breast cancer among women in their 40s.

摘要

Randomised controlled trials of breast cancer screening, when analysed as they were intended, have shown a significant reduction in breast cancer deaths by screening from age 40 years onwards.1 Only through inappropriate, unplanned, retrospective subgroup analyses of these trials were women aged 40-49 years told that screening held no benefit for them.2 Despite the fact that these studies lacked the statistical power to permit use of these subanalyses to make medical recommendations,3 the myth that the age of 50 years held real biological importance was born and perpetuated. Subsequent analyses grouped women aged 40-49 years together and compared them with women older than 50 years, artificially implying that these two groups were uniform and that a sudden jump in the results of screening occurred at 50 years, when no sudden changes actually occur at that age or any other.