Sex differences in lung cancer incidence and mortality in Russia in the light of computed tomography usage expansion: breakpoint and age-period-cohort analyses

Background: Russia has one of the highest lung cancer burdens globally, particularly in men. Mortality started to decline in the 1990s after the reduction in smoking prevalence. However, Russia's recent experience is largely unknown. This study aims to describe recent trends in the incidence and mortality of lung cancer in Russia along with the use of computed tomography (CT). Methods: We obtained incidence data from national cancer reports covering 1993-2021 and mortality and population data from the Russian Fertility and Mortality Database covering 1965-2021. The number of CT scanners was obtained from the OECD. Changes in age-standardized rates (Segi-Doll, per 100,000) were assessed using segmented regression and temporal effects using age-period-cohort analysis. Results: Lung cancer rates in men have been substantially higher than in women and have declined sharply since their peak in the 1990s. The latest breakpoints in incidence in women were in 2012 (95 % CI: 2000; 2014) from stagnation with an annual change of 0.7 % (-0.2; 1.5) to 3.4 % (1.6; 5.2) increase. In men, the decrease in incidence stopped in 2013 (2011; 2014) from -1.8 % (-2.1; -1.4) to 0.3 % (-0.7; 1.3). The growing number of CT scans accompanied the recent changes in incidence rates. Incidence declined sharply in 2020 in men and women. There were no substantial changes in declining mortality trends. Period effects were visible after 2012 when incidence rates increased and deviated from mortality. After accounting for the period effect, generations born after the 1950s had lower risks. Conclusion: Increasing lung cancer incidence rates in Russia in the late 2010s, especially in women, and the stable mortality trends could be a possible sign of diagnostic or treatment period effect. The increased use of CT should be monitored for possible benefits and harms.