Researchers Examined 36 Cancer Types & These 3 Risk Factors Top The List
For decades, cancer has been framed as something that “just happens.” A roll of the genetic dice. A matter of bad luck. And while biology will always play a role, a sweeping new global analysis suggests that this story is incomplete—and, in some ways, unnecessarily disempowering.
Ahead of World Cancer Day 2026, researchers from the World Health Organization’s International Agency for Research on Cancer released one of the most comprehensive assessments1 of cancer prevention ever conducted. Their question was simple: How many cancer cases around the world could be avoided if known risk factors were reduced or eliminated?
The answer is startling. According to the analysis, nearly four in ten new cancer cases globally are linked to factors we already know how to prevent. That’s not a theoretical projection; it’s based on real-world data from millions of people across nearly every region of the globe.
Rather than pointing to a single habit or lifestyle choice, the study reveals a broader truth: cancer risk is deeply shaped by patterns—how we live, where we live, what we’re exposed to, and what prevention tools are available to us.
A global look at cancer & risk
Published in Nature Medicine1, the analysis examined cancer incidence data from 185 countries, spanning 36 cancer types, from lung and colorectal cancer to cervical, stomach, and skin cancers. Researchers focused on data from 2022, the most recent year with complete global reporting, and paired it with exposure data from roughly a decade earlier to reflect the long timeline of cancer development.
In total, the team assessed 30 modifiable risk factors, including behavioral habits, environmental exposures, occupational risks, and infectious diseases. Using established epidemiological models, they calculated how many cancer cases could be attributed to these factors, both globally and within specific regions and populations.
The scale alone makes this study remarkable. But what truly sets it apart is the clarity of its conclusion.
Prevention could change millions of outcomes
The researchers estimate that 37.8% of new cancer cases worldwide (about 7.1 million diagnoses in a single year) were associated with preventable risk factors.
The burden was not evenly shared. Men accounted for a larger proportion of preventable cases overall, with roughly 45% of male cancers tied to modifiable risks, compared to about 30% among women. These differences likely reflect variations in smoking rates, occupational exposures, and access to preventive care.
Geography mattered, too. Women in sub-Saharan Africa experienced the highest proportion of cancers linked to modifiable risks, while men in East Asia saw the greatest overall burden, with more than half of cancer cases associated with preventable exposures.
The biggest culprits driving preventable cancer cases
When the researchers ranked the most influential risk factors worldwide, three stood out clearly:
- Tobacco use, responsible for about 15% of all new cancer cases
- Infections, accounting for just over 10%
- Alcohol consumption, linked to more than 3%
Together, these exposures explain a significant share of the global cancer burden. Lung, stomach, and cervical cancers alone made up nearly half of all preventable cases, each tied closely to specific risks like smoking, Helicobacter pylori infection, and human papillomavirus (HPV).
Notably, infections emerged as the leading cancer risk factor for women globally, while smoking dominated among men, a distinction with major implications for prevention strategies.
Accounting for cancer-causing infections
For the first time in a global analysis of this scale, researchers evaluated nine cancer-linked infections together, including HPV, hepatitis B and C, Epstein–Barr virus, and H. pylori, along with several parasitic infections associated with bladder and bile duct cancers.
What makes this especially significant is that many of these infections are largely preventable through vaccination, screening, and early treatment. The challenge, as the authors emphasize, is unequal access. In lower-income regions, limited healthcare infrastructure allows preventable infections (and their downstream cancer risks) to persist.
What you can do to reduce your personal risk
This study reframes cancer prevention as both a personal and structural issue. At a population level, it underscores the urgency of tobacco education, vaccination programs, infection screening, and environmental protection.
At an individual level, small, consistent changes in your daily habits can meaningfully reduce your cancer risk. Quitting smoking, moderating alcohol intake, maintaining a healthy weight, staying physically active, and getting recommended vaccinations and screenings are all evidence-based strategies that work.
Importantly, the findings also suggest that prevention doesn’t require perfection. Even partial reductions in exposure, across multiple risk factors, could shift outcomes at a massive scale.
The takeaway
Cancer will never be entirely preventable. But this analysis makes one thing clear: we're not powerless against it.
Nearly 40% of cancer cases trace back to modifiable risk factors—things we can actually do something about. That's not a small number. It represents millions of lives that could potentially be changed through better choices, smarter policies, and more accessible preventive care.