Increasing Burden of Early-Onset Cancers: Disentangling the Contributions of Changes in Risk from Demographic Shifts

Sep 22, 2026

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Early-onset cancers are rising, drawing scientific and media attention, yet the drivers remain unclear. Cancer registry data from Switzerland (1982–2021) separate changes in age-standardized risk from demographic forces of population growth and aging. Early-onset cases are diagnosed at ages 20–49 and later-onset at 50+. Baseline rates (1982–1986) estimate expected cases, then observed-minus-expected quantifies risk contribution, with the remainder attributed to demographics. Demographics explain about three quarters of the early-onset increase, with site- and sex-specific variation.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages7

Reading Time18 min

AccessFree to download

Abstract

Methods and definitions

Results: early-onset vs later-onset

Significance

Introduction

Background and public health relevance

RESEARCH ARTICLE [https://doi.org/10.1158/2767-9764.CRC-26-0176](https://doi.org/10.1158/2767-9764.CRC-26-0176) OPEN ACCESS Increasing Burden of Early-Onset Cancers: Disentangling the Contributions of Changes in Risk from Demographic Shifts Axelle Braggion1,2, Bernadette Wilhelmina Antonia van der Linden1,3, Stefano Tancredi1,2, Sabine Rohrmann4,5, Stphane Cullati1,2,3, and Arnaud Chiolero1,2,6 􀀶 ABSTRACT The burden of early-onset cancers is increasing, attracting scientific and media attention. There is, however, a need to disentangle the contribution of changes in risk, that is, age-standardized rate, due to changes in carcinogenic exposure or detection practices, from the contribution of population growth and aging, and to determine how these contributions differ for later-onset cancers. Using cancer registry data, we estimated these contributions in Switzerland between 1982 and 2021. Early-onset cancers include any cancer diagnosed in adults between 20 and 49 years, whereas later-onset cancers are those diagnosed at 50 years or older. To estimate the contribution of changes in risk, we computed the expected number of cases by applying the 1982 to 1986 (baseline) agestandardized rates to subsequent populations and calculated the difference between observed and expected cases. To estimate the contribution of population growth and aging, we subtracted the risk contribution from the total change in observed cases relative to 1982 to 1986. Between 1982 to 1986 and 2017 to 2021, the burden of early-onset cancers increased by 1,534 cases/year and that of later-onset cancers increased by 19,832 . For early-onset cancers, population growth and aging explained 71% of the increase (men: 102%; women: 58%) and changes in risk explained the remaining 29%(men: 􀀁2%; women: 42%) . These proportions differ by cancer site, with risk contributing to a higher proportion for prostate cancer, colorectal cancer, and melanoma. For lateronset cancers, population growth and aging explained 92% of the increase (men: 116%; women: 81%) and changes in risk explained the remaining 8%(men: 􀀁16%; women: 19%) . Further research is needed to clarify whether risk changes are due to changes in carcinogenic exposure or in detection practices. Significance: Although population growth and aging are known to contribute to increasing cancer burden, their relative contribution compared with risk changes has not been quantified for early-onset cancers. Using four decades of Swiss cancer registry data, we show that demographics explain about three quarters of the increase in early-onset cases, whereas risk changes account for the remaining quarter. Contributions vary by cancer site and sex, with implications for prevention and healthcare planning. Introduction The growing burden of early-onset cancers, defined as cancers diagnosed before 50 years, has attracted considerable scientific and media attention ( 1–6). This increase is part of a broader increase in the overall cancer burden 1Population Health Laboratory (\#PopHealthLab), University of Fribourg, Fribourg, Switzerland. 2Swiss School of Public Health (SSPH+), Zurich, Switzerland. 3Swiss Center of Expertise in Life Course Research LIVES, Lausanne, Switzerland. 4Cancer Registry of the Cantons of Zurich, Zug, Schaffhausen, and Schwyz, University Hospital Zurich, Zurich, Switzerland. 5Epidemiology, Biostatistics and Prevention Institute (EBPI), University of Zurich, Zurich, Switzerland. 6School of Population and Global Health, McGill University, Montreal, Canada. Corresponding Author: Axelle Braggion, Population Health Laboratory (\#PopHealthLab), Route des Arsenaux 41, Fribourg CH-1700, Switzerland. E-mail: [axelle.braggion@unifr.ch](axelle.braggion@unifr.ch) doi: 10.1158/2767-9764.CRC-26-0176 This open access article is distributed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. ©2026 The Authors; Published by the American Association for Cancer Resear

FAQs

How were changes in risk and demographic shifts separated in the study?

The study estimated the expected number of cases by applying 1982–1986 age-standardized incidence rates to later populations, then compared observed to expected cases to quantify the risk contribution. The remaining difference in observed cases relative to 1982–1986 was attributed to population growth and aging.

What age ranges define early-onset and later-onset cancers?

Early-onset cancers include cancers diagnosed in adults aged 20 to 49 years. Later-onset cancers are cancers diagnosed at age 50 years or older.

What proportion of the increase in early-onset cancer burden was explained by demographics versus risk changes?

Between 1982–1986 and 2017–2021, population growth and aging explained 71% of the increase in early-onset cancers overall (men: 102%; women: 58%), while changes in risk explained the remaining 29% (men: −2%; women: 42%).

What further research is recommended regarding risk changes?

Further research is needed to clarify whether observed risk changes result from shifts in carcinogenic exposure or from changes in detection practices.

Sep 22, 2026

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