Nearly four out of every ten cancer cases worldwide are linked to things people can actually change, according to a sweeping new analysis, and Bay Area public health voices say that means a lot of future diagnoses in San Francisco do not have to happen. The findings put cancer prevention squarely in two lanes at once: personal choices like quitting tobacco or staying current on vaccines, and policy decisions that shape access to care, clean air and robust vaccination programs.
The global numbers
The study estimated that 7.1 million of the 18.7 million new cancer cases in 2022, or about 37.8 percent, were tied to 30 modifiable risk factors, based on incidence data spanning 36 tumor types in 185 countries, according to Nature Medicine. To account for the time it takes cancer to develop, researchers paired 2022 cancer incidence with how common those exposures were roughly a decade earlier, and produced country-specific and sex specific estimates that showed just how uneven the burden is around the world.
Biggest drivers and who is most affected
Global experts on the paper pointed to tobacco, infections and alcohol as the heavy hitters. Cigarette smoking alone was tied to roughly 15 percent of cases, infections to about 10 percent and alcohol to about 3 percent, with lung, stomach and cervical cancers together making up nearly half of all preventable cases, according to the WHO. Men carried a much larger share of preventable cancers, about 45 percent, compared with women at about 30 percent, reflecting different exposure patterns across regions and lifestyles.
Why this matters here
The paper dropped at the start of February to coincide with World Cancer Day and quickly filtered into local conversation, with CBS News Sacramento turning to Bay Area physicians to ask what residents can realistically do right now. Their advice was not flashy, just effective: stop smoking if you can, keep up with recommended vaccines, and do not blow off routine screening appointments.
How to cut your risk
Some of the most powerful moves, both individually and at the public health level, are already on the books. Vaccination against HPV and hepatitis B, detection and treatment of Helicobacter pylori, and participation in recommended screening programs for cervical, breast and colorectal cancers all significantly cut risk. According to the National Cancer Institute, HPV vaccination lowers the chance of developing several cancers, while large scale screening programs catch disease earlier when it is far more treatable. Quitting smoking remains the single biggest individual lever to reduce cancer risk, and federal help with counseling and cessation is available through the CDC and state run quit lines.
“Addressing these preventable causes represents one of the most powerful opportunities to reduce the global cancer burden,” Dr. Isabelle Soerjomataram, a senior author on the study, said in a WHO statement. The study team and WHO called for coordinated policy steps, including stronger tobacco control, wider vaccination coverage, tighter air quality standards and measures to reduce harmful alcohol use, and cautioned against framing cancer prevention as something that rests only on individual willpower.
In the Bay Area, local providers such as UCSF’s Helen Diller Family Comprehensive Cancer Center and community clinics offer screening, vaccination programs and support for people trying to quit tobacco. For many San Franciscans, the first practical move is simple: check in with a primary care clinician about which vaccines and age-appropriate screenings are due. Taken together, the new analysis suggests those small, routine steps could translate into a big drop in future cancer cases.
