Cancer incidence and mortality trends from 2007 to 2021 in Milan

The objective of this study is to evaluate long-term cancer incidence and mortality trends in the Italian provinces of Milan and Lodi (2007-2021), with a specific focus on the impact of the COVID-19 pandemic in 2020. Data from the Milan Cancer Registry, covering 3.5 million inhabitants, were analyzed. Cancer cases were classified using International Classification of Diseases-O-3 and mortality data with International Classification of Diseases-10 codes. The age-standardized rates were then computed. Joinpoint regression estimated trends excluding 2020 to avoid distortions, including sensitivity analyses. Quality indicators were preliminarily assessed. Overall, 335 849 cases were registered (173 058 males; 162 791 females). Incidence declined among males [annual percent change (APC) -1.9%/year, 2007-2021], driven by prostate, lung, colorectal, and bladder cancers. Female incidence showed heterogeneous patterns, stabilizing and modestly decreasing in recent years (APC -0.6%/year, 2011-2021). Mortality declined steadily in both sexes (-1.9%/year in males; -2.1%/year in females). In 2020, incidence rates dropped sharply compared with 2019 (-19% males; -13% females), reflecting diagnostic delays and competing mortality, but returned to baseline in 2021. Increases were limited to thyroid and testicular cancers, which are largely linked to differences in diagnostic intensity and exposure differences. Cancer incidence decreased among males and stabilized or slightly declined among females, while mortality continued to decrease in both sexes. The abrupt 2020 reduction reflects pandemic disruptions but has a limited long-term effect. These findings confirm the crucial role of population-based cancer registries in monitoring trends and supporting health policy.