Temporal changes in age at diagnosis and the proportion of early-onset cases among diagnosed cases of 16 selected cancers in the United States, 2000–2023
Registry analysis reveals shifting age distributions and falling early-onset shares across US cancer cases, highlighting site-specific rises in colorectal cancer.
Key Points
To evaluate temporal changes in the age distribution and the proportion of early-onset diagnoses among adults with 16 common cancers in the United States from 2000 to 2023.
Descriptive registry-based analysis of 12,910,291 diagnosed cancer cases aged ≥ 20 years across 16 cancer sites in the United States using the SEER-21 database.
Calculated mean and median age at diagnosis and determined the early-onset proportion, defined as cases diagnosed at ages 20–49 years divided by total cases aged ≥ 20 years.
The overall mean age at diagnosis declined from 65.24 years in 2000 to 64.30 years in 2014, before rising to 65.40 years in 2023.
The early-onset case proportion (ages 20–49 years) rose from 13.17% in 2000 to a peak of 13.61% in 2005, then dropped to 11.55% in 2023, representing an absolute decline of −0.77 percentage points from 2014 to 2023.
Trends differed substantially by anatomical site; while overall early-onset proportions declined, the proportion for colon and rectum cancer increased by +3.75 percentage points between 2014 and 2023.