title: Population-Based Effects of Mammography Screening in Bavaria on the Distribution of TNM-T Categories with Respect to Different Histological Subgroups.
abstract: BACKGROUND
  Organized mammography screening was implemented in Bavaria in 2003, with a target population of about 1.5 million women (aged 50-69 years). We evaluated the population-based effects of mammography screening on the distribution of tumor-node-metastasis (TNM)-T categories with regard to different histological subgroups of breast cancer.
  
  
  METHODS
  Women diagnosed with breast cancer between 2002 and 2008 were included. The annual age-specific incidence rates separated by T category were calculated for different histological subgroups and plotted against time. Time trends were analyzed not only in the screening population but also based on women aged 15-49 and ≥70 years, respectively. Furthermore, correlation coefficients were calculated in order to evaluate the possible association between participation rate and incidence of certain TNM-T categories.
  
  
  RESULTS
  With ductal carcinomas, the incidence of early-stage tumors shows a strong increase in the screening population and a significant correlation with the participation rate, whereas with lobular carcinomas there is a stagnation of incidence in women aged 50-69 years irrespective of TNM-T category.
  
  
  CONCLUSIONS
  Short-term effects of mammography screening can already be demonstrated. However, depending on breast cancer type, not all women appear to benefit from screening. The expected long-term reduction of breast cancer mortality remains to be seen.
authors.affiliation: Population-Based Cancer Registry Bavaria, Erlangen, Germany.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Braisch
authors.forename: Karla
authors.initials: K
authors.lastname: Geiss
authors.forename: Martin
authors.initials: M
authors.lastname: Radespiel-Tröger
authors.forename: Martin
authors.initials: M
authors.lastname: Meyer
keywords: Breast cancer; Histological types; Mammography; Screening
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