The Many Causes of Cancer: How Environment, Work, Lifestyle and Infections Shape Our Risk

Discover how environment, work, lifestyle, and infections shape cancer risk and learn strategies to prevent it effectively.

Why We Need to Rethink Cancer Prevention

Cancer does not have a single cause. Instead, it emerges from a complex web of factors that interact throughout a person’s life. This idea is captured by the concept of the exposome, which looks at all the environmental, lifestyle, and social influences we are exposed to from conception onwards. From air pollution and chemicals at work, to lifestyle habits, infections, and even the effects of climate change, these overlapping risks combine to shape who develops cancer and how it progresses. Understanding the exposome is key to prevention—and to reducing the millions of new cancer cases diagnosed worldwide each year.

What Is the Exposome and Why Does It Matter in Cancer Research?

While traditional cancer research often focused on isolating single causes, the exposome provides a new framework. It views human health, and cancer risk, as the result of a lifetime of combined exposures—environmental, lifestyle, and social. It complements the genome and changes the research question from “What single factor caused this cancer?” to “How did a lifetime of interacting exposures lead to this outcome?”

ISGlobal’s Research Areas on Cancer

Cancer Today: Global and Local Trends

Cancer remains a major global health challenge. In 2022, there were nearly 20 million new cancer cases and about 9.7 million deaths worldwide. In Spain, 279,000 new cases and 116,000 deaths were recorded. A worrying trend is the rise of early-onset cancers, such as colorectal cancer in younger adults, linked to lifestyle, obesity, diet, and early-life exposures.

Occupational Cancer: The Hidden Burden

Despite abundant knowledge about workplace carcinogens, occupational cancer remains underdiagnosed in Spain. Officially, only about 50 cases are recognized each year, but estimates suggest the real figure is between 3,000 and 6,000. This gap represents a major public health crisis.

• Workplace carcinogens: asbestos, crystalline silica dust, and others.
• Research findings: occupational exposures linked to bladder cancer.
• The challenge: long latency periods make recognition and prevention difficult.

Circadian Rhythms and Cancer: When the Body Clock Breaks

The body’s 24-hour rhythm regulates many biological processes. Disruption from night shifts or irregular schedules is now considered a “probable carcinogen.” Studies have shown links between long-term night work and higher risks of breast, prostate, and colorectal cancer.

• Night work and health risks.
• Chrononutrition: research shows that earlier dinner times reduce risks of prostate and breast cancer.

The Urban Exposome: How Cities Shape Cancer Risk

By 2030, over 80% of Europeans will live in cities. Research shows that the urban environment—pollution, green spaces, noise, and light at night—affects cancer risk and even prognosis.

• Air pollution, artificial light, and green spaces.
• Social inequalities in exposure and health outcomes.

Climate Change and Cancer: A Multiplier of Risks

Climate change is not a single factor but a “threat multiplier” that amplifies cancer risks through many pathways.

• Air pollution, heat waves, wildfires, and droughts increase carcinogenic exposures.
• New projects are evaluating how climate and workplace factors interact to affect health.

Infections and Cancer: The HPV Example

Infections account for about 16% of cancers worldwide. The link between Human Papillomavirus (HPV) and cervical cancer led to the development of effective HPV vaccines.

• HPV prevention is a global health success.
• Cervical cancer incidence highlights inequities in health systems, especially in low-income regions.

Towards an Integrated Future of Cancer Prevention

Exposome research offers a new, integrated view of cancer. From viruses to climate change, it shows that cancer is driven by combined exposures and must be prevented through multifaceted strategies. The exposome provides a roadmap for bridging science and policy—addressing not only biological causes but also social, economic, and political factors.
The HPV prevention story shows what is possible when knowledge translates into policy. But underdiagnosed occupational cancers are a reminder of the challenges ahead. A proactive, integrated, and equitable approach is essential for the future of cancer prevention.