About 40% of cancer cases can be prevented

About 40% of cancer cases can be prevented, according to the 2025 annual report of the American Association for Cancer Research (AACR). The report emphasizes that a significant share of cases is linked to modifiable risk factors, meaning prevention and public health programs play a key role.

Among the main factors:

• Smoking, responsible for nearly 30% of cancer-related deaths in the U.S. Even quitting after many years reduces the risk.
• Lifestyle — poor diet, excess weight, alcohol consumption, and lack of physical activity cause more than 20% of new cases. Red meats and processed meats, sugary drinks, and ultra-processed foods increase the risk; vegetables, fruits, fish, and whole grains reduce it.
• Vaccination and infections — the HPV vaccine can almost completely prevent certain forms of cancer, yet vaccination rates remain low.
• Environmental and occupational risks — exposure to chemicals, radiation, and night-shift work increases the likelihood of illness.
• Psychological factors — chronic stress, anxiety, and depression may affect immunity and increase cancer risk.