Effect of mammography screening on surgical treatment for breast cancer: a nationwide analysis of hospitalization rates in Germany 2005-2009.

The aim of this study was to assess the association between the introduction of the nationwide mammography screening program (MSP) and breast cancer surgery rates in Germany 2005-2009. We used nationwide DRG hospitalization files (2005-2009) and analyzed surgery rates for the treatment of invasive and in situ breast cancer in Germany. We used actual numbers of screened women to model the influence of the introduction of the MSP on surgery rates. During 2005 through 2009, the rate of breast-conserving surgery for invasive and in situ breast cancer increased among all age groups. However, rate increases for invasive and in situ breast surgery were largest among women aged 50-69 years (invasive: rate difference [per 100,000] 95.1, 95 % CI 90.7; 99.5; in situ: rate difference 34.4, 95 % CI 32.6; 36.2). Mastectomy rates generally showed little change over time. Conditional on a 70 % participation in the MSP, our model predicts that the estimated increase of mastectomy rates for invasive and in situ breast cancer among women aged 50-69 years during the introductory phase of the MSP would be 4.2 (95 % CI -0.2; 8.6) and 6.1 per 100,000 (95 % CI 5.0; 7.1), respectively. The introduction of the nationwide MSP shows markedly rising rates of breast conserving surgery for women aged 50-69 years with invasive and in situ breast cancer. This increase is expected as a consequence of the first screening round. The model-based estimate for the increase of mastectomy rates, assuming a 70 % MSP participation, is lower than the reported increases observed in MSP in other countries.