Increasing Cancer Incidence in Iowa: A 22-Year Regional Comparative Analysis with the Seven Surrounding States

BACKGROUND: Iowa has the second-highest overall cancer incidence rate (IR) in the United States and is one of three states with increasing IRs. We aim to identify site- and stage-specific drivers of Iowa's increasing IRs compared with seven surrounding states combined. METHODS: Sex-specific trends in age-standardized IRs (overall, site-specific, and stage-specific), mortality rates (MR; 2001-2022), and screening and risk factor prevalence (1992-2022) were examined in both regions using joinpoint regression. Iowa-to-surrounding-state IR and MR ratios and prevalence ratios were calculated. RESULTS: After earlier stable trends, Iowa's overall cancer IR increased 0.6% annually among males (2013-2022) and females (2005-2022). From 2013 to 2022, Iowa's largest IR increases were for prostate, melanoma, and kidney cancers among males and breast, melanoma, and uterine cancers among females, predominantly at localized stage; advanced-stage prostate and breast cancer IRs also slightly increased. Overall IRs were comparable between regions through 2013; thereafter, IRs increased in Iowa but remained stable in surrounding states. In 2022, Iowa's overall IRs exceeded surrounding states by 11% among males and 6% among females. Prostate cancer accounted for 43.5% of male divergence, and breast and lung cancers for 57.8% among females. MRs declined in both regions. Screening and risk factor prevalence trends were generally comparable between regions, although trends in male binge drinking were less favorable in Iowa compared with those in surrounding states. CONCLUSIONS: Iowa's increasing incidence largely coincided with increasing localized-stage IRs, particularly among detection-sensitive cancers, whereas cancer mortality declined. IMPACT: Increasing cancer incidence, particularly advanced-stage disease at selected sites, warrants sustained preventive intervention in Iowa.