Up to 40% of Cancer Cases Are Preventable, New Study Finds

Cancer remains a leading cause of death worldwide, and recent trends show increasing diagnoses even in younger adults. However, new research offers a hopeful message: a significant proportion of cancer cases are potentially preventable. A study published in Nature Medicine estimates that up to 37% of new cancer cases in 2022 – around 7.1 million diagnoses – were linked to factors that could be modified through behavioral changes. This translates to nearly four in ten cancer cases globally potentially being avoided.

The study, which analyzed data from 185 countries and 36 cancer types, identified 30 preventable causes. While the specific causes varied by region and sex, certain factors consistently emerged as major contributors. Around 30% of cancer cases in women and 45% in men were deemed preventable.

“This shifts the conversation from cancer being driven mainly by genetics or bad luck to one where prevention plays a central role,” explains Amar Rewari, M.D., chief of radiation oncology for Luminis Health. “It reinforces a powerful and often underappreciated message that a large share of cancer risk is not inevitable.”

What are the leading preventable causes of cancer?

The researchers identified several key risk factors, broadly categorized as behavioral, environmental, and occupational. The most prevalent causes include tobacco smoking, alcohol consumption, obesity, insufficient physical activity, smokeless tobacco use, air pollution, ultraviolet radiation, and infection.

The relative importance of these factors differed geographically. In higher-income countries, lifestyle choices like smoking, obesity, and alcohol consumption played a larger role. Conversely, in lower-resource settings, infection-related cancers were more prominent. This highlights the impact of factors like overcrowding, poor sanitation, limited access to clean water, and vaccine availability.

For example, the study noted a higher incidence of stomach cancer linked to H. Pylori infections in Japan and Korea, while liver cancer diagnoses associated with hepatitis B and C infections were more common in Africa. Increased access to vaccines and screenings has already demonstrated success in reducing these types of cancers, though significant work remains.

“This highlights the need for prevention strategies that are tailored to where people live and the risks they face, rather than a one-size-fits-all approach,” Dr. Rewari says.

Why are the findings significant?

The study’s findings challenge common misconceptions about cancer and emphasize the potential for proactive prevention. According to Dr. Rewari, the research reinforces the idea that a substantial portion of cancer risk is modifiable. The consistent impact of a relatively small number of risk factors – tobacco, infections, alcohol, obesity, and physical inactivity – is particularly noteworthy.

“One major takeaway is how consistently a small number of risk factors drive a large share of the global cancer burden,” Dr. Rewari points out. “Tobacco remains the single largest contributor worldwide.”

The results also underscore the success of past cancer prevention efforts focused on reducing exposure to risk factors, such as tobacco use and certain infections, rather than solely relying on treatment advancements.

What does this mean for you?

The good news is that individuals can take concrete steps to reduce their cancer risk. “Everyday choices and environments matter,” Dr. Rewari says. “Avoiding tobacco in all forms remains the single most important step to reduce cancer risk. Limiting alcohol, staying physically active, and maintaining a healthy weight can also make a meaningful difference over time.”

Staying up-to-date on vaccinations, including those for hepatitis B and human papillomavirus (HPV), is also crucial. Dr. Rewari emphasizes that these vaccines are powerful tools for cancer prevention, not just infection prevention.

However, it’s important to remember that even with these preventative measures, cancer risk cannot be entirely eliminated. “Individual actions are important, but so are broader policies that support clean air, safer workplaces, and access to preventative care,” Dr. Rewari says. “Cancer prevention works best when people are supported by healthier environments and policies, not left to do it all on their own.”

The bottom line

While the study’s findings are promising, further research is needed to refine our understanding of cancer prevention. Dr. Rewari cautions against overinterpreting the term “preventable,” noting that cancer development is a complex process influenced by multiple factors over decades.

“These numbers are based on large-population studies, so they’re meant to show big-picture patterns rather than explain why any one individual developed cancer,” he explains. “Still, even with those nuances, the takeaway is clear, which is that reducing well-known risk factors at a population level could prevent millions of cancers over time.”