Trends in cancer mortality under age 50 in 15 upper-Middle and high-income countries.

Background: Rising cancer incidence, particularly for colorectal cancer, has been reported in young adults. This study examined whether this is related to an increase in mortality.

Methods: We analysed World Health Organization (WHO) mortality data among young adults aged 25-49 in 15 most populous upper-middle and high-income countries from 1990 to 2021 with reliable data. Mid-year populations were retrieved from the United Nations for the American Countries and from the WHO for the other countries. We compared age-standardised mortality rates (ASMRs) in 2019-2021 to 2009-2011 and performed joinpoint regression analysis for all cancers and selected most common cancer sites: colorectum, pancreas, lung and breast.

Results: In 2019-2021, the highest ASMRs (per 100,000) were in Romanian males (38.6) and Argentinian females (45.9), while the lowest ones in Japan (males: 16.3; females: 22.7). ASMRs for colorectal cancers increased in 2019-2021 compared to 2009-2011 in nine countries among men and in seven countries among women. The highest increases were in the UK (males: +26.1%; females: +33.7%), Canada (males: +25.3%), and Mexico (males: +33.5%; females: +29.7%). Long-term analysis over the last three decades showed declining trends in total cancer mortality in the majority of countries, in lung cancer mortality across all countries, and in breast cancer in all countries except in Latin America.

Conclusions: While mortality from common cancers has generally decreased over the past three decades, mortality from colorectal cancer has increased in some countries. This highlights the need to control the obesity epidemic and implement targeted surveillance strategies in young populations.