Impact of screening on breast cancer mortality: the UK programme 20 years on
Menée en Angleterre à partir de données portant sur 869 patientes décédées d'un cancer primitif du sein entre 2008 et 2009 (âge au décès : 47 à 89 ans) et sur 1 642 témoins en population générale, cette étude évalue le bénéfice, en termes de réduction du nombre de décès par cancer mammaire, d'un programme de dépistage organisé
Background : With changes in diagnosis, treatment and management of breast cancer since the mammography screening trials, there is a need to evaluate contemporary breast screening programmes. A case-control study was set up to assess the current impact of attendance in the English Breast Screening Programme on breast cancer mortality.
Methods : Cancer registry cases who died from primary breast cancer aged 47-89 in London in 2008-2009 (869 women) were matched to 1 or 2 general population controls (1,642 women) with no diagnosis of breast cancer at the time of the case's diagnosis, who were alive at the case's death. Cases and controls were matched for date of birth and screening area, and had been invited to breast screening at least once prior to the case's diagnosis. Odds ratios (OR) were estimated using conditional logistic regression. Self-selection bias was addressed using contemporaneous attendance at the cervical screening programme. Sensitivity analyses were undertaken to assess the likely effect of lead time bias.
Results : Attendance at breast screening resulted in a breast cancer mortality reduction of 36% (OR=0.64, 95%CI 0.45-0.88) after self-selection correction. Attendance in the last 3 years prior to diagnosis resulted in a 61% mortality reduction (OR=0.39, 95%CI 0.30-0.50). Lead time bias effects were negligible.
Conclusions : Our results suggest that community breast screening programmes provide their expected benefit in terms of reducing the risk of breast cancer death among women participating.
Impact : Mammography is an important tool for reducing breast cancer mortality and its impact could be increased by encouraging regular attendance.
Cancer Epidemiology Biomarkers & Prevention , résumé, 2015