Recent data suggest that people born between 1965 and 1980, known as Generation X, have higher incidence rates of some cancers (eg, thyroid, colorectal, kidney, uterine corpus, and leukemia) and an increased risk of all leading cancers combined. Published in The Lancet Public Health, an analysis of population-based registry data from the North American Association of Central Cancer Registries expanded on past research of differences in cancer rates among adults. This comprehensive report provides trends in incidence rates of 34 cancers and mortality rates of 25 cancers for 2000 to 2019 by birth cohort spanning 1920 to 1990 in the US.
Data were extracted for over 23.5 million patients. Incidence rates continued to increase in successively younger generations for half of the cancer types covered in the research, including 9 cancer types that had previously been declining in incidence among older adults. Specifically, the incidence rates for cancers of the small intestine, thyroid, kidney and renal pelvis, and pancreas were approximately 2 to 3 times higher in the 1990 birth cohort compared with the 1955 birth cohort. The birth cohort effect on incidence trends was significant for 8 of 11 cancers. Incidence rates for uterine corpus, estrogen receptor-positive breast, and gallbladder and other biliary cancers increased across almost all age groups, with faster increases among younger age groups. Mortality rates increased in conjunction with the incidence trends for several cancer types (ie, liver [female], uterine corpus, gallbladder, testicular, and colorectal cancers), suggesting the rise in incidence in younger generations is substantial enough to outweigh improvements in cancer survival.
This research has important public health implications and highlights the need to identify and address underlying risk factors. The increase in incidence among younger generations suggests possible rise in the prevalence of carcinogenic exposures during early life or young adulthood. Additionally, more than half of the cancers with increasing incidence in younger generations are obesity-related cancers, suggesting a potential role of obesity in emerging cancer trends in recent generations. The authors emphasized the need for population-level interventions, stating that without appropriate intercession, an overall increase in cancer burden could occur as younger generations age, halting or reversing decades of progress against the disease.
High level
The authors suggest that investigations into the various mechanisms contributing to the differences in cancer rates among adults are needed. Specifically, they encourage a comprehensive life course framework approach in epidemiologic research to address knowledge gaps in modifiable carcinogenic exposures. Intervention strategies that align with the social and cultural context, values, and preferences of the younger generations, as well as programs and services targeted to younger adults, are also important.
Ground level
The differences in cancer rates among adults highlight the need for increased awareness of rising cancer incidence rates in younger generations. Especially for younger adults, healthcare providers must remain vigilant for the signs and symptoms of cancer to facilitate early detection and treatment.