France: worrying increase in cancers among under-50s

Early-onset cancers, defined as those occurring before the age of 50, are increasing significantly worldwide. Between 1990 and 2019, the number of new cases jumped by nearly 80%, from 1.82 million to 3.26 million.[1]This phenomenon, described by some researchers as an "emerging epidemic", is of particular concern to health professionals in France, where the trends are following the same dynamic, according to a study conducted in partnership by Santé publique France, the National Cancer Institute (INCa) and the Francim registry network.[2].

The study highlights a steady rise in several types of cancers in adolescents and young adults (AYA), including colorectal, breast and renal carcinomas, Hodgkin lymphomas, glioblastomas and liposarcomas. This increase in early cancers raises crucial questions about risk factors and the need for tailored prevention strategies, according to the authors.

A marked increase among adolescents and young adults

The incidence of cancer among 15-39 year-olds in France increased by 1.62 % per year between 2000 and 2014 before experiencing a slight decrease of 0.79 % between 2015 and 2020. During these twenty years, 54,735 new cases of cancer were recorded in 19 French departments, representing 24 % of the national territory.[3].

The most common types of cancer differ by age and sex. In men, testicular germ cell tumors largely dominate with 24.8 % of cases, followed by Hodgkin lymphomas (8.7 %), melanomas (10 %) and gastrointestinal carcinomas (8.6 %). In women, breast cancer is the most common, accounting for 30.4 % of cases, followed by thyroid cancer (16.3 %) and melanoma (10.8 %).

Worrying variations in incidence

The evolution of the incidence of cancers in young French adults between 2000 and 2020 shows worrying trends. Colorectal cancer increased by 1.43 % per year, representing a total increase of nearly 30 % over the period studied. Breast cancer increased by 1.60 % per year, representing an increase of more than 35 % in 20 years. Kidney cancer experienced an explosion of more than 120 %, with an annual increase of 4.51 %. Glioblastomas, aggressive brain tumors, tripled in 20 years, with an increase of 6.11 % per year. The incidence of Hodgkin's lymphoma increased by 1.86 % per year, representing a total increase of nearly 40 %. Finally, liposarcomas, rare soft tissue cancers, increased by 3.68 % per year, reaching an increase of more than 90 % in two decades.

These increases are not specific to France. In the United States, a study published in 2024 in The Lancet[4] shows that young people born in 1990 are two to three times more likely to develop certain digestive cancers than those born in 1955. Another study reveals that in 2022, 1.3 million adolescents and young adults will have been diagnosed with cancer worldwide[5].

The multiple causes of these increasing incidences

The exact causes of this increase remain unclear, but several factors are suspected, warn the authors. The Western lifestyle, combining increased sedentary lifestyle, ultra-processed diet, obesity and exposure to pollutants, seems to play a key role. According to estimates from the International Agency for Research on Cancer (IARC), nearly 40% of early cancers could be avoided by acting on these factors.

Alcohol, tobacco and obesity are at the top of the identified causes. For example, drinking alcohol increases the risk of breast cancer by 15%, while being overweight and obese are involved in 13 to 17% of digestive and renal cancers. Endocrine disruptors, present in cosmetics, plastics and certain foods, are also suspected of acting on the development of hormonal cancers, such as breast and thyroid.

Some digestive cancers, such as colorectal and pancreatic, are particularly sensitive to environmental exposures. Food additives and pesticides could alter the intestinal microbiota and promote tumor formation. Prolonged hormonal contraception is also a subject of study: women using hormonal contraceptives in the long term have a 20 to 30% higher risk of breast cancer.

Promote early detection and strengthen prevention

In light of these findings, the authors call for increased awareness-raising initiatives on risky behaviors, particularly regarding diet, physical activity, tobacco and alcohol consumption, and exposure to toxic substances. Improving epidemiological surveillance, particularly through cancer registries, is essential to better understand current trends and anticipate future developments.

Experts stress the need to adapt screening and prevention strategies. Currently, in France:

• Breast cancer screening begins at age 50, while the increase in incidence among those under 50 could justify lowering the age to 45, or even 40 for women at risk.
• Colorectal cancer screening begins at age 50, but several studies suggest that early testing as early as age 45 may be beneficial.
• No specific strategy is in place to detect kidney or pancreatic cancers early., yet increasing sharply.

Improving cancer monitoring registries will also help refine data and better understand future trends, according to experts. In the absence of collective awareness and appropriate prevention measures, projections indicate that by 2030, one in ten colorectal cancers and one in four rectal cancers will affect patients under 50.

Beyond improving screening, it is crucial to strengthen prevention to slow the increase in early cancers. Tobacco and alcohol consumption, two major risk factors, must be targeted by stricter public health measures. A strengthened anti-smoking policy, including strong measures such as significant increases in taxes on tobacco products and more impactful awareness campaigns have already proven their effectiveness in reducing smoking in France. In addition, the care of smokers wishing to quit must be improved, which requires an adequate supply of care.

The alarming rise in cancers in France and worldwide cannot be dissociated from the broader issue of the commercial determinants of health. Behind these increasing figures lies the persistent influence of industries whose products and practices contribute to the exposure of populations to toxic substances. Faced with this public health issue, the response cannot be limited to the medical care of patients: it requires strong regulatory action to regulate the supply of harmful products and the activities of the manufacturers concerned.

©Generation Without Tobacco

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[1] Jianhui Zhao, Liying Xu, Jing Sun, Mingyang Song, Lijuan Wang, Shuai Yuan, Yingshuang Zhu, Zhengwei Wan, Susanna Larsson, Konstantinos Tsilidis, Malcolm Dunlop, Harry Campbell, Igor Rudan, Peige Song, Evropi Theodoratou, Kefeng Ding, Xue Li - Global trends in incidence, death, burden and risk factors of early-onset cancer from 1990 to 2019: BMJ Oncology 2023;2:e000049.

[2] Study, Incidence and its evolution between 2000 and 2020 of cancers in adolescents and young adults (15-39 years) in French departments covered by a general cancer registry. Study based on the cancer registries of the Francim network (EPI-AJA 2022 Project), Public Health France, published March 3, 2025, consulted March 5, 2025

[3] The authors estimate that the incidence at the national level is based on the assumption that the incidence in the area covered by the cancer registries is similar to the national incidence over the entire period but also by year.

[4] Differences in cancer rates among adults born between 1920 and 1990 in the USA: an analysis of population-based cancer registry data Sung, Hyuna et al. The Lancet Public Health, Volume 9, Issue 8, e583 - e593

[5] The current and future global burden of cancer among adolescents and young adults: a population-based study Hughes, Taylor et al. The Lancet Oncology, Volume 25, Issue 12, 1614 - 1624