A recent study conducted in the United States highlights a concerning trend: specific types of cancer are being diagnosed more frequently in younger adults. This study, funded by the government and involving 17 National Cancer Institute registries, was published in the journal JAMA Network Open on a Wednesday. It meticulously examined over half a million cases of early-onset cancer, referring to instances of cancer diagnosed in individuals under the age of 50, spanning the years from 2010 to 2019.
The results of the study reveal an overall rise in early-onset cancer cases over the course of that decade, with an average annual increase of 0.28%. The driving force behind this increase appears to be the surge in cancer rates among younger women, which exhibited an average annual growth of 0.67%. Concurrently, cancer rates in men saw a decrease of 0.37% annually.
The study notes that there were 34,233 instances of early-onset cancer in women in the year 2010, which then rose to 35,721 cases in 2019—an uptick of 4.35%. Among men, however, cases decreased by 4.91%, dropping from 21,818 in 2010 to 20,747 in 2019.
Furthermore, while the rate of cancer diagnosis remained steady in other age groups under 50, the study found an increase in cancer diagnosis rates among adults in their 30s over the course of the decade. Conversely, the rates of cancer among individuals aged 50 and older exhibited a decline.
Upon analyzing cancer trends among younger adults by racial categories, the researchers discovered the swiftest rise in early-onset cancers among individuals identifying as American Indian or Alaska Native, Asians, and Hispanics. On average, the rates of early-onset cancer remained stable among White individuals and decreased among Black individuals between 2010 and 2019.
In 2019, the types of cancer with the highest numbers of early-onset cases included breast cancer (12,649 cases), thyroid cancer (5,869 cases), and colorectal cancer (4,097 cases). The most notable increases in early-onset cases were observed in cancers of the appendix (a 252% increase), bile duct cancers (a 142% increase), and uterine cancer (a 76% increase).
The study also highlighted a rapid growth of nearly 15% in the incidence rates of early-onset cancers affecting the gastrointestinal tract from 2010 to 2019. Previous research has indicated a rise in cancers of the digestive system, especially colorectal cancers, among adults under the age of 55 since the 1990s.
Importantly, these trends are not limited to the United States. A study conducted last year, which reviewed cancer registry records from 44 countries, found a significant increase in the incidence of early-onset cancers for 14 different types of cancer, many of which affect the digestive system. The authors of that review attribute this rise to factors such as more sensitive screening tests and other causes that warrant further investigation.
The researchers responsible for the present study emphasize that their findings should prompt healthcare providers to consider the possibility of tumors when treating patients under the age of 50.