Randomized controlled trial of mammographic screening from age 40 ('Age' trial): patterns of screening attendance

Background The Age trial was a randomized controlled trial to study the effect on breast cancer mortality of invitation to annual mammography from age 40 to 41. Uptake of invitation to screening mammography in UK women aged below 50 is of interest, particularly in the light of the recent announcement that the national breast screening programme will begin inviting women from age 47. Methods The trial took place in 23 National Health Service breast screening units in England, Wales and Scotland between 1991 and 2004. Data on invitation and attendance during 13 years of trial fieldwork were analysed. The participants were 53,884 women in the intervention arm of the Age trial who were randomized to receive annual invitation to mammography from age 40 or 41 up to age 48. The trial is registered as an International Standard Randomised Controlled Trial, number ISRCTN24647151. Results Uptake of invitation to routine screening was 68% at first round and 69% at subsequent rounds. A total of 43,709 women in the intervention arm (81%) attended at least one routine screen and 23,262 (43%) attended at least seven screens; 31,392 women attended 75% or more of all routine invitations they were offered. Previous trial attendance was a predictor of subsequent uptake; attendance was inversely related to Townsend deprivation score. Conclusion Uptake in this trial was comparable with that in the UK screening programme for women aged over 50. There was an inverse relationship between deprivation level and the number of screens attended.