Preventable Cancer Cases in the U.S. Linked to Modifiable Risk Factors

Nearly 40% of all cancer cases and almost half of cancer deaths among adults aged 30 and older in the United States are linked to modifiable risk factors1 . These factors include cigarette smoking, excess body weight, alcohol consumption, physical inactivity, diet, and infections, all of which can be changed to reduce cancer risk2 . Understanding which risk factors contribute most and why they remain prevalent is essential for effective cancer prevention and control3 .

Leading Preventable Cancer Risk Factors

Cigarette smoking remains the most significant modifiable risk factor for cancer in the U.S., accounting for approximately 19.3% of all cancer cases and nearly 30% of cancer deaths in 20192 . Smoking is strongly linked to lung cancer, which has the highest number of cases and deaths attributable to modifiable risks, but it also increases the risk for cancers of the urinary bladder, colorectal region, oral cavity, larynx, pharynx, and esophagus4 52. Lung cancer risk is elevated about 25-fold among smokers compared to non-smokers6 .

Excess body weight, measured by high body mass index (BMI), is the second leading factor, contributing to 7.6% of cancer cases and 7.3% of cancer deaths2 . Obesity is dose-dependently associated with increased risk of multiple cancers, including breast, colorectal, pancreatic, endometrial, gallbladder, esophageal, liver, and kidney cancers7 82. The rising prevalence of obesity and related metabolic factors is a growing concern and may soon surpass tobacco as the leading preventable cause of cancer9 .

Alcohol consumption accounts for about 5.4% of cancer cases and 4.1% of deaths2 . Alcohol is classified as a Group 1 carcinogen with no known safe threshold, yet public awareness of its carcinogenic risk remains low10 8. Alcohol use is linked to cancers of the oral cavity, pharynx, esophagus, liver, colorectal region, and breast, with higher proportions of alcohol-attributable cases observed in men2 3.

Other important modifiable risk factors include ultraviolet (UV) radiation exposure, which causes 4.6% of cancer cases, mainly skin melanoma, and physical inactivity, contributing to 3.1% of cases2 . Dietary factors such as low consumption of fruits, vegetables, dietary fiber, and calcium, as well as high intake of red and processed meat, also contribute to cancer risk, particularly colorectal cancer11 2.

Human papillomavirus (HPV) infection is a major preventable cause of cervical cancer and other anogenital and oropharyngeal cancers, with vaccination being a key preventive measure12 132. Hepatitis B virus (HBV) vaccination also reduces liver cancer risk2 .

“Despite considerable declines in smoking prevalence during the past few decades, the number of lung cancer deaths attributable to cigarette smoking in the United States is alarming. This finding underscores the importance of implementing comprehensive tobacco control policies in each state to promote smoking cessation, as well as heightened efforts to increase screening for early detection of lung cancer, when treatment could be more effective.”

— Farhad Islami, MD, PhD, American Cancer Society15

Reasons Modifiable Risks Cause High Cancer Rates

Several factors explain why modifiable risk factors continue to cause a large proportion of cancer cases and deaths despite strong evidence linking them to cancer risk.

First, public awareness of the cancer risks associated with many lifestyle factors remains insufficient. Knowledge gaps are especially notable for alcohol consumption, diet, and physical inactivity, which limits effective prevention efforts16 . For example, alcohol is a known carcinogen with no safe consumption threshold, yet many people underestimate its cancer risk10 8.

Second, the prevalence of obesity and related metabolic factors is increasing rapidly in the U.S. and worldwide, driven by energy imbalance from poor diet and sedentary behavior. This trend threatens to surpass smoking as the leading preventable cause of cancer in the near future9 17. Obesity is dose-dependently linked to increased risk of multiple cancers, including breast, colorectal, and pancreatic cancers, and is particularly concerning among younger individuals7 83.

Third, social norms and misconceptions challenge efforts to communicate the risks of alcohol and processed foods. These factors are often culturally ingrained and may be perceived as less harmful than smoking, complicating public health messaging10 16.

Fourth, disparities in access to preventive healthcare, including vaccinations, screening, and cessation programs, contribute to ongoing cancer risk. For example, HPV vaccination uptake in the U.S. remains suboptimal despite its proven effectiveness in preventing cervical and other cancers2 15.

Finally, some modifiable risk factors, such as smoking and infections, are more common among vulnerable populations, including people with HIV infection, underscoring the need for targeted interventions2 .

There is a continued need to increase equitable access to preventive health care and awareness about preventive measures. Effective vaccines are available for hepatitis B virus that causes liver cancer and HPV, which can cause several cancer types, including cervical, other anogenital, and oropharyngeal cancers15 .

Strategies for Reducing Your Cancer Risk

Reducing cancer risk requires a comprehensive approach targeting the leading modifiable factors through individual behavior change and public health policies.

• Tobacco Cessation: Expanding comprehensive tobacco control programs, including increasing cigarette taxes, smoke-free policies, and cessation support, can have the greatest impact on reducing cancer cases and deaths2 15. Lung cancer screening with low-dose CT scans for high-risk individuals also improves early detection and survival3 .

• Maintaining Healthy Weight: Interventions to prevent and reduce obesity through balanced diet and physical activity are critical. Obesity prevention can substantially reduce the incidence of several cancers, especially breast, colorectal, and pancreatic cancers9 78.

• Limiting Alcohol Consumption: Public education about the carcinogenic risks of alcohol and promoting moderation or abstinence can lower cancer risk. Although no safe level of alcohol exists, harm reduction guidelines recommend limiting intake to no more than one drink per occasion and three per week10 83.

• Healthy Diet: Increasing consumption of whole grains, fruits, vegetables, and dietary fiber while limiting red and processed meats and sugar-sweetened beverages supports cancer prevention, particularly for colorectal cancer11 18.

• Physical Activity: Regular exercise, including 150–300 minutes of moderate-intensity or 75–150 minutes of vigorous-intensity aerobic activity weekly, with muscle-strengthening activities, reduces cancer risk. Even brief bouts of vigorous exercise throughout the day are beneficial14 8.

“The study provides an excellent overview of the modifiable factors that contribute to the burden of cancer in the USA. Clearly, continuing to raise awareness around cigarette smoking remains a top priority but excess body weight, alcohol consumption, physical inactivity and low fruit and vegetable consumption are all top-ranking risk factors.”

— Nigel Brockton, PhD, American Institute for Cancer Research20

• Sun Protection: Using sunscreen, wearing protective clothing, and avoiding tanning beds effectively prevent melanoma and other skin cancers14 8.

• Vaccination: HPV and hepatitis B vaccinations are proven to prevent virus-associated cancers. Increasing vaccination coverage, especially among eligible adolescents and high-risk groups, is essential12 132.

• Improving Public Awareness: Addressing knowledge gaps about alcohol, diet, and physical inactivity through education and policy interventions can enhance prevention efforts16 .

“An estimated 40 percent of all cancer cases and nearly one half of all cancer deaths in the U.S. are attributable to the evaluated modifiable risk factors. These findings reinforce that cancer and early death from cancer can be substantially reduced through prevention.”

— Farhad Islami, MD, PhD, American Cancer Society3

1. Avoid all tobacco products and seek cessation support if needed2 .
2. Maintain a healthy body weight through balanced diet and regular physical activity9 .
3. Limit alcohol intake or abstain entirely10 .
4. Eat a diet rich in whole grains, fruits, vegetables, and fiber; limit processed and red meats11 .
5. Protect your skin from UV radiation with sunscreen and protective clothing14 .
6. Get vaccinated against HPV and hepatitis B according to recommended schedules12 13.
7. Participate in recommended cancer screening programs for early detection19 .