Key TakeawaysAn American Cancer Society study found that 40% of all cancer cases in the U.S. are due to modifiable risk factors like smoking, obesity, and alcohol consumption.While some cancers are hereditary, genetic factors account for only 5–10% of cancers, with lifestyle factors being the primary contributors to cancer risk.

Key Takeaways

An American Cancer Society study found that 40% of all cancer cases in the U.S. are due to modifiable risk factors like smoking, obesity, and alcohol consumption.While some cancers are hereditary, genetic factors account for only 5–10% of cancers, with lifestyle factors being the primary contributors to cancer risk.

According to the study, 40% of all cancer cases and about half of cancer deaths in the United States can be attributed to modifiable risk factors, including cigarette smoking, excess body weight, alcohol consumption, physical inactivity, diet, and infections such as HPV, which can cause cervical and other cancers.

In fact, that 40% may be an undercount.

“Add in factors for which we don’t have enough data yet, such as the impact of water and air pollution, and lifestyle factors may be [responsible for] 60% or higher,” lead study authorFarhad Islami, MD, PhD, Senior Scientific Director for Cancer Disparity Research at the American Cancer Society told Verywell.

“These findings show there is a continued need to increase equitable access to preventive health care and awareness about preventive measures,” said study senior authorAhmedin Jemal, DVM, PhD, Senior Vice President of Surveillance and Health Equity Science at the American Cancer Society,in a statement.

What You Can Control

According to the American Cancer Society, modifiable risk factors to help prevent cancer include:

What You Can’t Control

Some cancers are hereditary. ButHuma Rana, MD, MPH, Clinical Director of Cancer Genetics and Prevention at the Dana Farber Cancer Institute in Boston, emphasizes that not many are.

Most people who have a family history of cancer are not at increased risk for developing cancers because most cancers aren’t the result of inherited susceptibility.

However, there are exceptions.

Lynch syndromeis a hereditary condition linked to higher susceptibility to colorectal cancer and uterine cancer. It’s responsible for about 3% of all colorectal cancers.According to the National Cancer Institute, Lynch syndrome affects about 1 out of every 280 Americans.

Separately, people who’ve inheritedBRCA1 or BRCA2 gene mutationshave an increased risk of breast and ovarian cancers, among others. Roughly 1 in 400 people are living with a BRCA mutation, upping their risk of developing breast cancer to over 60%, compared to 13% in the general population.

Genetic testing can determine if you have inherited either Lynch syndrome or a BRCA mutation, as well as your individual cancer risk from these genetic traits. You may be able to undergo more frequent or earlier screenings for the relevant cancer types.

What This Means For YouThis study underscores the importance of adopting healthy lifestyle habits, such as quitting smoking, maintaining a healthy weight, and reducing alcohol consumption, to significantly lower your cancer risk. By focusing on modifiable risk factors, you can take proactive steps to prevent cancer and improve your overall health.

What This Means For You

This study underscores the importance of adopting healthy lifestyle habits, such as quitting smoking, maintaining a healthy weight, and reducing alcohol consumption, to significantly lower your cancer risk. By focusing on modifiable risk factors, you can take proactive steps to prevent cancer and improve your overall health.

7 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Islami F, Marlow EC, Thomson B, et al.Proportion and number of cancer cases and deaths attributable to potentially modifiable risk factors in the United States, 2019.CA Cancer J Clin. Published online July 11, 2024. doi:10.3322/caac.21858Shaukat A, Kahi CJ, Burke CA, Rabeneck L, Sauer BG, Rex DK.ACG clinical guidelines: colorectal cancer screening 2021.Am J Gastroenterol. 2021;116(3):458-479. doi:10.14309/ajg.0000000000001122US Preventive Services Task Force, Nicholson WK, Silverstein M, et al.Screening for breast cancer: US Preventive Services Task Force recommendation statement.JAMA. 2024;331(22):1918-1930. doi:10.1001/jama.2024.5534National Cancer Institute.The genetics of cancer.American Cancer Society.Colorectal cancer risk factors.National Cancer Institute.Could a vaccine prevent colorectal cancer in people with Lynch syndrome?.National Cancer Institute.BRCA gene changes: cancer risk and genetic testing.

7 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Islami F, Marlow EC, Thomson B, et al.Proportion and number of cancer cases and deaths attributable to potentially modifiable risk factors in the United States, 2019.CA Cancer J Clin. Published online July 11, 2024. doi:10.3322/caac.21858Shaukat A, Kahi CJ, Burke CA, Rabeneck L, Sauer BG, Rex DK.ACG clinical guidelines: colorectal cancer screening 2021.Am J Gastroenterol. 2021;116(3):458-479. doi:10.14309/ajg.0000000000001122US Preventive Services Task Force, Nicholson WK, Silverstein M, et al.Screening for breast cancer: US Preventive Services Task Force recommendation statement.JAMA. 2024;331(22):1918-1930. doi:10.1001/jama.2024.5534National Cancer Institute.The genetics of cancer.American Cancer Society.Colorectal cancer risk factors.National Cancer Institute.Could a vaccine prevent colorectal cancer in people with Lynch syndrome?.National Cancer Institute.BRCA gene changes: cancer risk and genetic testing.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Islami F, Marlow EC, Thomson B, et al.Proportion and number of cancer cases and deaths attributable to potentially modifiable risk factors in the United States, 2019.CA Cancer J Clin. Published online July 11, 2024. doi:10.3322/caac.21858Shaukat A, Kahi CJ, Burke CA, Rabeneck L, Sauer BG, Rex DK.ACG clinical guidelines: colorectal cancer screening 2021.Am J Gastroenterol. 2021;116(3):458-479. doi:10.14309/ajg.0000000000001122US Preventive Services Task Force, Nicholson WK, Silverstein M, et al.Screening for breast cancer: US Preventive Services Task Force recommendation statement.JAMA. 2024;331(22):1918-1930. doi:10.1001/jama.2024.5534National Cancer Institute.The genetics of cancer.American Cancer Society.Colorectal cancer risk factors.National Cancer Institute.Could a vaccine prevent colorectal cancer in people with Lynch syndrome?.National Cancer Institute.BRCA gene changes: cancer risk and genetic testing.

Islami F, Marlow EC, Thomson B, et al.Proportion and number of cancer cases and deaths attributable to potentially modifiable risk factors in the United States, 2019.CA Cancer J Clin. Published online July 11, 2024. doi:10.3322/caac.21858

Shaukat A, Kahi CJ, Burke CA, Rabeneck L, Sauer BG, Rex DK.ACG clinical guidelines: colorectal cancer screening 2021.Am J Gastroenterol. 2021;116(3):458-479. doi:10.14309/ajg.0000000000001122

US Preventive Services Task Force, Nicholson WK, Silverstein M, et al.Screening for breast cancer: US Preventive Services Task Force recommendation statement.JAMA. 2024;331(22):1918-1930. doi:10.1001/jama.2024.5534

National Cancer Institute.The genetics of cancer.

American Cancer Society.Colorectal cancer risk factors.

National Cancer Institute.Could a vaccine prevent colorectal cancer in people with Lynch syndrome?.

National Cancer Institute.BRCA gene changes: cancer risk and genetic testing.

Meet Our Medical Expert Board

Share Feedback

Was this page helpful?Thanks for your feedback!What is your feedback?OtherHelpfulReport an ErrorSubmit

Was this page helpful?

Thanks for your feedback!

What is your feedback?OtherHelpfulReport an ErrorSubmit

What is your feedback?