A recent study published in the journal JAMA Network Open reveals that certain types of cancer are being diagnosed more frequently in younger adults in the United States. The study, which analyzed more than 500,000 cases of early-onset cancer (diagnosed in patients under 50) between 2010 and 2019, found that the overall rate of early-onset cancers increased by an average of 0.28% each year during this period.
The increase in early-onset cancer cases was primarily driven by higher rates in younger women, which rose by an average of 0.67% annually, while rates in men decreased by 0.37% each year. In 2010, there were 34,233 early-onset cancer cases in women, compared to 35,721 in 2019, representing a 4.35% increase. In contrast, cases among men declined by 4.91%, from 21,818 in 2010 to 20,747 in 2019.
The study also revealed that the incidence of cancer diagnosis increased in adults in their 30s over the decade, while remaining stable in other age groups under 50. However, the rate of cancer diagnosis in adults aged 50 and older decreased during the same period.
When examining cancer trends in younger adults by race, the study found that early-onset cancers were rising most rapidly among individuals who identify as American Indian or Alaska Natives, Asians, and Hispanics. Conversely, the growth rates of early-onset cancers remained stable in White people and decreased in Black people between 2010 and 2019.
The most commonly diagnosed early-onset cancers in 2019 were breast cancer (12,649 cases), thyroid cancer (5,869 cases), and colorectal cancer (4,097 cases). The cancers with the largest increases in early-onset cases were appendix cancer (252% increase), bile duct cancer (142% increase), and uterine cancer (76% increase).
The study also noted that the incidence rates of early-onset cancers of the gastrointestinal tract, particularly colorectal cancer, have been increasing since the 1990s among adults younger than 55. This trend is not unique to the United States, as a review of cancer registry records in 44 countries found a rapid increase in early-onset cancers for several types, particularly those affecting the digestive system.
The researchers suggest that health care providers should consider the possibility of tumors when treating patients under 50, based on these findings. The increase in early-onset cancers warrants further investigation into potential causes, including the impact of more sensitive screening tests.