What are the patterns in the incidence of early-onset cancers?

By Dr. Priyom Bose, Ph.D.Aug 21 2023Reviewed by Sophia Coveney

Recent data seems to suggest that, among people younger than 50 years, the incidence of early-onset cancers is on the rise. However, the availability of updated data is limited.

A recent JAMA Network Open study studied the patterns in the incidence of early-onset cancers between 2010 and 2019 in the United States. The study provided granular data on cancers that have the fastest-growing incidence rates.

Background

Cancer has traditionally been considered a disease that affects individuals who are 50 years and older, i.e., older adults. However, emerging data suggests that the incidence of cancer among patients younger than 50 years is on the rise. This is collectively called early-onset cancer.

Cancers affect a variety of organ systems, including the colon, head and neck, kidney, breast, and so on. The increase in early-onset cancers could be linked to other factors, such as changes in the environment, exposure to smoke and gas, and sleep patterns. Cancer is significantly associated with mortality and morbidity.

About the study

Recent research has analyzed the incidence patterns of certain types of early-onset cancers. However, a comprehensive overview of the same is not available. The current study utilized population-based data obtained from the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) program. The primary aim was to characterize the temporal patterns in the incidence of early-onset cancers, overall and by organ system, in the period between 2010 and 2019. The secondary aim was to explore temporal stratification by individual characteristics, such as sex, age group, and race, and ethnicity.

In terms of the characteristics of the sample, a total of 562,145 patients were considered. 62.5% of the participants were female. 4,565 patients were American Indian or Alaska Native; 54,876 were Asian or Pacific Islander; 61,048 were Black; 118,099 were Hispanic; 314,610 were White; and 8,947 were of unknown ethnicity and/or race.

Key findings

It was observed that the overall incidence rate of early-onset cancers increased between 2010 and 2019. During the same period, the incidence rate of cancers decreased among individuals aged 50 years or older. During the study period, the incidence rates declined in male individuals but increased in female individuals. This increase among females was mainly driven by breast and uterus cancers.

An increased incidence was observed in Hispanic people, American Indian or Alaska Native people, and Asian or Pacific Islanders. It declined among Black people and remained stable among White people. The rate increased in individuals aged 30 to 39 years and remained stable in others who were younger than 50 years. In 2019, breast cancer accounted for the highest number of incident early-onset cases.

By organ system, the fastest-growing incidence rate was observed for gastrointestinal cancers, followed by urinary system and female reproductive system cancers. The most common types of cancer among gastrointestinal cancers were in the stomach, colon and/or rectum, and pancreas. The gastrointestinal early-onset cancers that showed the fastest-growing incidence rates were in the pancreas, intrahepatic bile duct, and appendix.

These findings are consistent with a recent Global Burden of Disease Study, which showed that the highest incident rates of early-onset cancer, standardized by age, were in countries that reported a high sociodemographic index, e.g., countries in North America. The data from the current study add to the existing literature.

More research is required to fully understand the reasons behind the disparities observed in the cancer patterns, namely, the increase in incidence rates among females, individuals between 30 and 39 years of age, Asian or Pacific Islanders, and American Indian or Alaska Native individuals.

The data provided here should aid public health specialists and healthcare policymakers and motivate future research on the concerning patterns observed.

Conclusions

Up-to-date data, large sample size, and detailed subgroup analyses by cancer sites and organ systems are the main strengths of this study. A key limitation, however, is the potential lack of generalizability of the findings to a non-American population. Further, there could have been underreporting or underdiagnosis among less observed populations, such as Black individuals.

In sum, this national cohort study documented that the incidence of early-onset cancers rose in the US between 2010 and 2019. Gastrointestinal cancers had the fastest-growing incidence rates, and breast cancer had the highest number of incident cases.

These data could have important implications for the development of funding priorities and surveillance strategies.