Effect of digital technologies on mammographic screening in the Republic of Kazakhstan.

Abstract

e13601 Background: Since 2011 breast cancer (BC) has been the most common cancer in the Republic of Kazakhstan (RK) with the incidence of 43 per 100,000, and the third most common cause for cancer deaths with 9.4 deaths per 100,000 in 2019. Nationwide population-based screening program was implemented in the RK in 2008 inviting women aged 50–60 years every 2 years, with the subsequent expansion of the target group age to 40-70 years in 2018. The majority of screening mammography units was screen-film units at a time of program’s initiation. Gradual conversion to digital mammography (DM) has begun in 2014. This paper examines the impact of digital technologies on BC screening results on the example of the largest city in the RK - Almaty. Methods: We analyzed BC screening indicators such as incidence, mortality, proportion of early stage cancers, cancer detection rate. In order to assess the influence of transition to DM we divided the studied period to two stages: stage A (2008-2013)- when screen-film mammography (SFM) was widely used, and stage B (2014-2019)- when DM became prevalent in screening. Results: 598,058 women underwent BC screening from 2008 to 2019 in Almaty, 969 cancers were detected. At a time of program introduction in 2008 all 10 units used for screening were SFM units. The number of SFM units steadily increased from 10 in 2008 to 19 in 2014 and to 30 in 2019. Proportion of DM units concomitantly grew from 0% in 2008 to 47% in 2014 and to 83% in 2019. During the stage A 282 BC cases were detected (cancer detection rate 1 per 100,000 investigations). During the period B 687 BC cases were identified (cancer detection rate 2 per 100,000 investigations). Proportion of early stage cancers (0-I stage) rose from 26.7% in stage A to 41.0% in stage B. Widespread implementation of screening in 2008 led to a steady increase in BC incidence from 51 per 100,000 in 2008 to 63 per 100,000 in 2014. A noticeable decline in BC incidence has been evident since 2015 following 7 years of BC screening with incidence rate as low as 47.2 per 100,000 in 2019. Proportion of early stage BC among all newly diagnosed cases increased from 73.6% in 2008 to 86.6% in 2019. The average proportion of early stage BC was 77.5% for period A compared to 85,9% for stage B. Mortality rate was also affected by screening- it dropped by 38% from 20.6 per 100,000 in 2008 to 12.8 per 100,000 in 2019. Conclusions: BC state in Almaty reflects the general situation with BC in the whole country. Mammographic screening positively affected both BC incidence and mortality in Almaty. Increased utilization of digital technologies in screening resulted in rise in the proportion of early (0-I) stage BC by 21.4% and in the proportion of I-II stage BC by 13%. We suggest that, based on these results, further digitalization of mammographic screening should be strongly advised and digital to screen-film units ratio should be one of the main indicators for BC screening quality audit.