Early-onset cancer—diagnosed in adults aged ≤ 50 years—is on the rise. Researchers have studied a variety of factors driving the trend, such as type of cancer. However, geographic locality might have as much, if not more, to do with it, according to a study by researchers at Fox Chase Cancer Center, a National Cancer Institute-designated Comprehensive Cancer Center research facility.
Using the US Cancer Statistics Public Use Research Database, the researchers collected data from adults aged 20 to 49 years with invasive cancer (excluding in situ cases) diagnosed from 2015 through 2020. They calculated the incidence for each state using the national rate as the reference. Then, they calculated a second set of rates, comparing each state to the US in terms of overall incidence and advanced-stage incidence for all early-onset cancers.
The resulting maps indicated that early-onset cancer cases are not evenly distributed. States with worse-than-national rates are frequently near each other geographically. For instance, the rate of early-onset female breast cancer was worse than the national rate in 17 states, 16 of which were located in the eastern half of the US (Hawaii was the 17th state). Similarly, most states with worse-than-national rates of digestive cancers were located in the eastern half of the US, with a concentration in the South. Rates of male genital cancers were worse than national rates in 18 states, primarily in the eastern half of the country (plus Montana, Nebraska, and Puerto Rico).
Three states in the Southeast, 7 in the Northeast, and Puerto Rico had the highest incidence of lymphohematopoietic cancers. Incidence rates of endocrine cancers were worse than national rates in 25 states, which the researchers found formed “a horizontal core of the country running from east to west,” plus Puerto Rico. Rates of urinary system cancers were worse than national rates in 17 contiguous states, from New Mexico to Pennsylvania.
Rates of female genital cancers were worse than national rates in 16 states, largely in the Midwest and South, plus California and Puerto Rico. Skin cancer, on the other hand, was a great leveler, with worse-than-national rates in 32 states, mostly in the northern portion of the country.
Kentucky and West Virginia had the highest overall and advanced-stage incidence rates of early-onset cancer for all cancer sites combined. They were followed by Arkansas, Connecticut, Florida, Georgia, Iowa, Louisiana, Maine, Missouri, New Jersey, New York, North Carolina, Ohio, and Pennsylvania.
According to the researchers, this study provides the first analysis of age-adjusted rates of early-onset cancer based on state-level population and case numbers. Geographic patterns in early-onset cancer, they suggest, indicate possible similarities that could relate to demographic, socioeconomic, behavioral, or environmental risks. “Focusing prevention efforts on the highest-incidence states for the most prevalent sites may reduce the rate of early-onset cancer nationally.”