Sex-based differences in histologic lung cancer incidence trends in the United States, 2005-2019

Decreases in lung cancer incidence in the United States (US) have paralleled decreasing smoking prevalence for several decades; however, recent data has revealed slower declines among females than males. Sex-based differences in histologic lung cancer-and specifically adenocarcinoma-for all 50 US states and the District of Columbia have never been investigated. Using population-based cancer registry data from the US Cancer Statistics, we examined age-adjusted histologic lung cancer incidence rates and trends by sex and state of residence at diagnosis. We compared state-level adenocarcinoma incidence to lung cancer screening (LCS) adherence and smoking prevalence estimates. Average annual percentage change (AAPC) and incidence rate ratios (IRR) were used to assess changes over time. Nationally, females experienced faster increases in adenocarcinoma incidence than males (1.75%/year vs. 0.35%/year), and slower decreases in incidence of squamous cell (-0.06%/year vs. -1.58%/year) and small cell carcinoma (-2.06%/year vs. -3.19%/year). Adenocarcinoma incidence increased significantly (AAPC>0) in 41 states among females compared to 10 among males. Significant adenocarcinoma increases in individuals under age 55 (IRR >1) occurred among females in six states (four in the southeastern US) and none among males. State-level LCS adherence was significantly associated with adenocarcinoma incidence among females (r = 0.39; p<.01) but not males, though screening cannot account for increases among females under age 55. Our results highlight sex-based differences in histologic lung cancer incidence trends, with specific concern for increases in adenocarcinoma in the southeastern US. Further research is needed into appropriate LCS eligibility criteria and the risk factors driving sex-based disparities.