Final results of the randomised, controlled UK Breast Screening Age trial after 23 years of follow-up showed that mammography screening from age 40 was associated with a significant relative reduction in breast cancer deaths.
Recruitment took place from October 1990 until September 2997. 53,883 women from general practitioners' lists were invited to begin annual screening at age 40 in the intervention group. A control group of 106,953 women in the control group received standard breast cancer screening from age 50. Participants were followed for a median of 22.8 years and deaths were compared before the invitation .
Benefits of early screening were most prominent at the 10-year follow-up where there was a 25% relative reduction in breast cancer deaths compared to the control group. Researchers estimated that 1150 women in the 40-49 years age group would need to be screened to prevent 1 breast cancer death.
Participation rates in screening were similar in both groups with low false-positive rates in the intervention group. For participants' first screen mammogram, the false-positive rate was 4.9% and for subsequent screenings, it was 3.2%.
Why it matters: Most women in the UK begin annual screening mammographies from the age of 50 in accordance with NHS guidelines. This study suggests that lowering the age range to begin screening to below 50 may reduce overall breast cancer deaths with minimal overdiagnosis burden. It also validates recommendations by the American College of Radiology and the Society of Breast Imaging to begin regular mammography screening from 40 years.
Source: The Lancet Oncology