Population-based cohort study of patterns of lung cancer diagnosed in adults under the age 50 years in the United States, 2000-2021

Although the incidence of several types of cancer diagnosed before age 50 years has increased, contemporary trends in early-onset lung cancer remain poorly defined. A population-based cohort study using the SEER 22 database investigated patterns of lung cancer incidence diagnosed in individuals at age 20-49 years from 2000 to 2021. In this period, early-onset lung cancer incidence declined overall (average annual percent chage -3.81%; 95% CI -4.01 to -3.64; p<0.001). Declines among females occurred later but were steeper for lung adenocarcinoma (-5.14% versus -2.82%), whereas males declined faster for non-small cell lung cancer and overall. Female declines were slower relative to males in Hispanic and non-Hispanic Black individuals (2.3-fold and 1.08-fold faster, respectively), whereas non-Hispanic White females declined 1.3-fold faster than males. Among Asian females, NSCLC incidence did not decline, ans LUAD increased through 2017 (+2.45%) and remained stable in Hispanic females. The authors conclude that early-onset lung cancer incidence declined overall from 2000 to 2021, except for persistent or rising LUAD among Asian and Hispanic females, which implicates emerging non-tobacco risk factors.