In a study reported in The Lancet Oncology, researchers working collectively as the Global Burden of Disease 2019 Adolescent and Young Adult Cancer Collaborators identified cancer incidence and mortality rates in 2019 among individual aged 15 to 39 years globally and according to country sociodemographic index status. They also calculated years of disability and life lost due to cancer in this age group.   

The study involved data from the Global Burden of Diseases, Injuries, and Risk Factors Study 2019. Incidence and mortality rates were estimated globally and according to country sociodemographic index quintiles. Years lived with disability and years of life lost were estimated and combined to yield estimates of disability-adjusted life-years.

Key Findings  

Worldwide in 2019, there were 1.19 million (95% uncertainty interval [UI] = 1.11–1.28 million) new cancer cases and 396,000 (95% UI = 370,000–425,000) deaths due to cancer among individuals aged 15 to 39 years.

The highest age-standardized incidence rates per 100,000 person-years were in the highest sociodemographic index quintile countries (59.6, 95% UI = 54.5–65.7) and high-middle sociodemographic index quintile countries (53.2, 95% UI = 48.8–57.9), followed by middle sociodemographic index quintile (38.3, 95% UI = 35.1–41.6), low-middle sociodemographic index quintile (29.4, 95% UI = 26.5–32.2), and low sociodemographic index quintile countries (25.0, 95% UI = 21.4–28.7).

The highest age-standardized mortality rates per 100,000 person-years were in low-middle sociodemographic index countries (14.2, 95% UI = 12.9­–15.6) and middle sociodemographic index countries (13.6, 95% UI = 12.6–14.8), followed by high-middle sociodemographic index (13.4, 95% UI = 12.4–14.3), low sociodemographic index (13.3, 95% UI = 11.6–15.2), and high sociodemographic index countries (9.2, 95% UI = 8.9–9.6).

Cancers in this age group contributed 23.5 million (95% UI = 21.9-25.2 million) disability-adjusted life-years to the global burden of disease in 2019, with 2.7% (95% UI = 1.9%–3.6%) of the total attributed to years lived with disability and 97.3% (95% UI = 96.4%–98.1%) attributed to years of life lost. Estimated disability-adjusted life-years in the highest to lowest sociodemographic index countries were 2.02 million, 4.52 million, 7.78 million, 5.97 million, and 3.19 million, respectively.  

Globally, cancer was the fourth-leading cause of death and tenth-leading cause of disability-adjusted life-years in this age group in 2019.

The investigators concluded, “Adolescent and young adult cancers contributed substantially to the overall adolescent and young adult disease burden globally in 2019. These results provide new insights into the distribution and magnitude of the adolescent and young adult cancer burden around the world. With notable differences observed across sociodemographic index settings, these estimates can inform global and country-level cancer control efforts.”

Elysia Alvarez, MD, of the Department of Pediatrics, Division of Pediatric Hematology/Oncology, University of California Davis School of Medicine, is the corresponding author for The Lancet Oncology article.

Disclosure: The study was funded by the Bill & Melinda Gates Foundation, American Lebanese Syrian Associated Charities, St Baldrick’s Foundation, and National Cancer Institute. For full disclosures of the study authors, visit thelancet.com.