Do breast cancer survivors benefit from mammography screening? A population-based study

Mammography screening reduces breast cancer mortality by approximately 25 % in the general population and might therefore also benefit breast cancer survivors. However, its impact on mortality rates in this group remains unstudied. We aimed to estimate the effect of mammography screening on breast cancer mortality in this population.

We used data from invitations to the regional mammography screening program in Funen, Denmark (1993-2007), before the nationwide program's rollout in 2008. Breast cancer mortality among invited survivors (study group) was compared to survivors of similar age in counties without screening programs (control group).

The study and control groups comprised 2109 invited breast cancer survivors and 15,417 non-invited breast cancer survivors. Of those, 406 (19 %) and 3385 (22 %) died from breast cancer within the follow-up period. The relative risk for invited versus not invited at 22 years of follow-up was 0.88 (95 %CI: 0.81-0.97). The relative risk for participants compared to a similar group in the control group of non-invited breast cancer survivors was 0.62 (95 %CI: 0.51-0.76).

Mammography screening might reduce breast cancer mortality less among breast cancer survivors than among the general population. However, this is most likely due to a lower participation rate among breast cancer survivors.