Although cancer incidence overall is declining in older adults, a study published in the August JAMA Open Network reports that so-called early-onset cancers in people younger than age 50 are increasing, especially in women.
The researchers examined data from 2010 to 2019 in the National Cancer Institute's Surveillance, Epidemiology, and End Results Program, a network of tumor registries from across the United States. Their analysis of 562,145 early-onset cases found that overall cancer rates increased by 0.28%, while rates in people ages 50 years and older decreased by 0.87%. The highest incidence of early-onset cancer was seen in women, people ages 30 to 39 years, and people of American Indian or Alaska Native, Asian or Pacific Islander, and Hispanic ethnicity.
Women were found to be at higher risk for early-onset cancer than men. The incidence rate for young women increased by 0.67% annually, while the rate for young men decreased by 0.37%. Much of the increase among women was due to breast cancer, which had the highest number of early-onset incident cases-over 12,000 cases in 2019, a 7.7% increase over 2009. Another contributor was uterine cancer, which ranked third among the early-onset cancers with the fastest-growing annual increases.
Gastrointestinal cancers followed breast cancer in the number of early-onset incident cases in 2019 with 7,383 cases, a 14.8% increase over the life of the study. The three organs with the highest number of incident cases were colon and/or rectum (n = 4,097), stomach (n = 773), and pancreas (n = 701). Gastrointestinal cases had the fastest-growing annual increases, with the steepest increases seen in cancers of the appendix, intrahepatic bile duct, and pancreas.
Other studies have found the same trends worldwide. Experts point to lifestyle risk factors as a possible explanation for the rise in early-onset cancers. These include obesity, smoking, alcohol consumption, and physical inactivity, along with environmental exposures to such hazards as smoke and pollution. Changes in the gut microbiome due to diets that include highly processed foods and sugary drinks are also thought to play a role.
Although people in the under-50 age group have likely experienced more cancer screenings over their lifetime compared to older Americans, the rise in cancer incidence is believed to reflect actual increases in the number of cases, not just an increase in the number being found. The authors recommend incorporating these trends into cancer surveillance strategies.-Karen Roush, PhD, RN, FNP-BC, news director