Breast cancer mortality after eight years of an improved screening program using digital breast tomosynthesis.

ABSTRACT

OBJECTIVES: To assess screening quality metrics and to describe mortality rates eight years after redesign of breast cancer screening and diagnosis pathways, and the introduction of digital breast tomosynthesis. SETTING: Breast Unit of the Toledo Health Area in the region of Castilla-La Mancha (Spain). METHODS: We recorded screening metrics and mortality data following the introduction of digital breast tomosynthesis in 2011 for screening and diagnosis pathways. We then compared the mortality between Toledo Health Area and the rest of Castilla-La Mancha, where digital breast tomosynthesis is not available. RESULTS: All screening quality metrics improved following the introduction of digital breast tomosynthesis. The cancer detection rate significantly increased from 2.3 (95% confidence interval (CI) 1.9-3.6) to 4.5 per 1000 women (95% CI 3.2-5.2) on average between the periods 2005-2009 and 2015-2018, while the recall rate significantly decreased from 7.0% (95% CI 6.8%-8.2%) to 2.6% (95% CI 2.0%-3.6%). Comparing breast cancer mortality rates for 2014-2018 in the Toledo Health Area with the rest of Castilla-La Mancha, which had similar cancer treatment access and management protocols but without digital breast tomosynthesis, the crude mortality rate was 17.79 (95% CI 15.38 -20.19) vs. 24.76 per 100,000 (95% CI 26.12-23.39), respectively. The cumulative risk of death was also significantly lower for the Toledo Health Area than for Castilla-La Mancha. CONCLUSION: The introduction of digital breast tomosynthesis improved screening quality indicators. Breast cancer mortality simultaneously decreased with respect to the rest of Castilla-La Mancha. Further research is needed to assess the long-term results, and the role that the redesign may have played in reducing mortality.