Breast cancer mortality and screening mammography in New Zealand: Incidence-based and aggregate analyses.

Objective: To investigate trends in breast cancer mortality in New Zealand women, to corroborate or negate a causal association with service screening mammography.

Method: Cumulated mortality rates from breast cancer deaths individually linked to incident cases diagnosed before and after screening commencement were compared, in women aged 50-64 (from 2001) and aged 45-49 and 65-69 (from 2006). Trends and differences in aggregate invasive breast cancer mortality (1975-2013) were assessed in relation to introduction of mammography screening targeting women aged 50-64 and 45-69.