Elsevier

Cancer Epidemiology

Volume 44, October 2016, Pages 44-51
Cancer Epidemiology

Trends in advanced breast cancer incidence rates after implementation of a mammography screening program in a German population

https://doi.org/10.1016/j.canep.2016.07.006Get rights and content
Under a Creative Commons license
open access

Highlights

  • Time trends of incident breast cancer were studied after start of a mammography screening program.

  • Advanced stage breast cancer rates (UICC II+) started to decline during fully implemented screening program.

  • Levels of advanced stage breast cancers after 8 years of screening were lower than in the pre-screen period.

  • Advanced stage breast cancer declines were not observed in women newly eligible for screening.

  • Findings appear to indicate that mammography screening lowers rates of advanced stage breast cancer in the population.

Abstract

Background

Mammography screening programs (MSPs) aim to detect early-stage breast cancers in order to decrease the incidence of advanced-stage breast cancers and to reduce breast cancer mortality. We analyzed the time trends of advanced-stage breast cancer incidence rates in the target population before and after implementation of the MSP in a region of northwestern Germany.

Methods

The MSP in the Münster district started in October 2005. A total of 13,874 women with an incident invasive breast cancer (BC) was identified by the population-based epidemiological cancer registry between 2000 and 2013 in the target group 50–69 years. Multiple imputation methods were used to replace missing data on tumor stages (10.4%). The incidence rates for early-stage (UICC I) and advanced-stage (UICC II+) BC were determined, and Poisson regression analyses were performed to assess trends over time.

Results

The incidence rates for UICC I breast cancers increased during the step-up introduction of the MSP and remained elevated thereafter. By contrast, after increasing from 2006 to 2008, the incidence rates of UICC II+ breast cancers decreased to levels below the pre-screening period. Significantly decreasing UICC II+ incidence rates were limited to the age group 55–69 years and reached levels that were significantly lower than incidence rates in the pre-screening period.

Discussion

The incidence rates of advanced-stage breast cancers decreased in the age groups from 55 years to the upper age limit for screening eligibility, but not in the adjacent age groups. The findings are consistent with MSP lead time effects and seem to indicate that the MSP lowers advanced-stage breast cancer rates in the target population.

Cited by (0)