Research News

The Global Burden of Adolescent and Young Adult Cancer in 2019

August 29, 2022

In a systematic analysis for the Global Burden of Disease Study 2019, the GBD 2019 Adolescent Young Adult Cancer Collaborators, including Khalifa University’s Dr. Juan Acuna, investigated the global impact of cancer in young people, with the results published in the Lancet.


In estimating the global burden of cancer, adolescents and young adults are often overlooked, despite being a distinct subgroup with unique epidemiology, clinical-care needs and societal impact. Because of this, comprehensive estimates of the global cancer burden in adolescents and young adults are lacking.


“Adolescents and young adults develop cancers commonly found and treated in the pediatric population, as well as the more common carcinomas seen in adults,” said Dr. Juan Acuna, Associate Professor and Chair, Department of Epidemiology and Public Health at Khalifa University. “Some cancers are more prevalent in this age group than in younger or older individuals, and from a health care-delivery perspective, adolescent and young-adult patients with cancer might struggle to find care that is optimal for both their cancer type and their age-related treatment needs.”


Additionally, this age group is more likely to face social and financial challenges that could result in inequities in access to appropriate care, timely diagnosis, and treatment. They are also not a targeted group for cancer-control programs and research development, despite their age group not seeing the same improvements in cancer survival as younger and older cohorts. Consideration of more comprehensive disease-burden metrics is especially relevant for this group as their disease burden might put a strain on their evolving careers and families.


This subgroup refers to people aged 15 to 39, as the definitions and cutoffs of the age range for adolescents and young adults vary. This age group is generally described as being in the transition between childhood and adulthood, making it a large subpopulation that needs representation in global studies.


Adolescents and young adults are often grouped with adult patients in clinical care and clinical trials, meaning comprehensive assessments of the cancer burden and epidemiological patterns in this age group are largely unknown or underreported. Previous studies have reported on global cancer incidence and mortality patterns in this group. However,the Global Burden of Diseases, Injuries and Risk Factors Study (GBD) is the only global disease-burden-estimation framework that evaluates disability-adjusted life-years (DALYs) for cancer as a metric to complement incidence and mortality data.


“DALYs are a key measure of disease burden that include both fatal and non-fatal impacts of disease and are used in the development of national and global health policy,” Dr. Acuna explained. “They represent an important comprehensive assessment of the burden of cancer in this distinctive population, adding to existing estimates of disease burden with more classic measures. They are crucial to informing cancer-control strategies that address health disparities and inequities in adolescents and young adults.”


The study found that there were an estimated 1.19 million incident cancer cases and 396,000 deaths due to cancer among individuals aged 15-39. Breast cancer, brain cancer, colon and rectum cancer, and stomach cancer were the four greatest contributors to the DALY burden globally for both sexes combined. However, if leukemias were considered as a single group, rather than as individual leukemia subtypes, they would be the largest category contributing to the global cancer DALY burden.


The results also show that the greatest burden of cancer in adolescents and young adults was concentrated in parts of Asia, southern sub-Saharan Africa, and South America. This geographical pattern was similar to that of childhood cancers. Women had a higher overall incidence of cancer than men globally in 2019 but overall mortality rates were similar.


In 2019, deaths due to cancer in the adolescent and young adult population were lower than those estimated for transport injuries and cardiovascular and circulatory diseases, but higher than those estimated for HIV/AIDS and sexually transmitted infections, respiratory infections and tuberculosis, and unintentional injuries.


“The global burden of cancer contributed more DALYs to the global disease burden than some high-profile communicable diseases such as HIV/AIDS,” Dr. Acuna said. “This comparison had not previously been documented, and it highlights that cancer is an important contributor to premature death and the disease burden in adolescents and young adults, even when compared to diseases that are the focus of more active global funding, research and advocacy efforts. Our findings underscore the need to develop a global strategy to address the cancer burden in this population.”


Because of the substantial burden of adolescent and young-adult cancers globally, there needs to be broader attention on the unique determinants driving cancer outcomes in this age range, the researchers concluded. The World Health Assembly in 2017 noted that patients in this population often experience delays and difficulties in assessing care, and the psychosocial challenges they face require resources and skills that are often not available to cancer-treatment teams.


“The age range for adolescents and young adults encompasses their formative years in life and spans the time from completing education to possibly starting a career and raising children, and potentially contributing to society more broadly,” Dr. Acuna explained. “A cancer diagnosis during these years can have considerable impact on their future life trajectory through major stressors, including feelings of isolation, anxiety and depression, concerns about infertility, discontinuing school or work, and financial hardship. Efforts to mitigate these issues have been successful but they’ve largely been limited to high-income countries. These initiatives need to be expanded globally, particularly to those countries which carry a disproportionate burden of adolescent and young adult cancer DALYs.”


To improve outcomes in this unique population, a new approach to global cancer control is required, the researchers said. Efforts to comprehensively estimate the global burden of cancer in adolescents and young adults, like this study, are a crucial first step. Increased awareness of the burden of cancer in this population could lead to targeted interventions for improved outcomes. 


Jade Sterling
Science Writer
29 August 2022