A recent study by the American Cancer Society highlights a concerning yet crucial reality: nearly two out of every five cancer cases and almost half of all cancer-related deaths in individuals over 30 in the United States are linked to controllable or modifiable risk factors.
These are lifestyle choices and behaviors that individuals can change, such as reducing alcohol consumption, quitting smoking, or increasing physical activity. The study underscores the profound impact of personal choices or cancer prevention, offering a sense of empowerment to those looking to reduce their risk of cancer.
Lead author Farhad Islami, MD, PhD, who serves as the senior scientific director of cancer disparity research at the American Cancer Society, notes that while the causes of cancer may often seem beyond our control, many factors are, in fact, within reach.
“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,” says Dr. Islami.
Top Controllable Risk Factors: Smoking, Obesity, and Alcohol Consumption
To understand the scope of cancer prevention, the study examined 18 different modifiable risk factors across 30 types of cancer, analyzing data from large-scale studies and meta-analyses.
Among these risk factors, smoking emerged as the leading cause, contributing to about 20% of all cancer cases and nearly 30% of cancer-related deaths.
Other significant preventable risk factors included excess body weight and alcohol consumption. Specifically:
- Excess Body Weight accounted for 7.6% of cancer cases and was closely linked with cancers such as endometrial, gallbladder, liver, esophageal, and kidney cancers.
- Alcohol Consumption was responsible for 5.4% of cases, with the highest number of cases linked to female breast cancer, followed by colorectal cancer in both men and women.
- Ultraviolet (UV) Radiation exposure accounted for 4.6% of cancer cases, particularly contributing to skin melanomas.
Additional modifiable risk factors included physical inactivity, poor diet (such as high consumption of red meat, low intake of fruits and vegetables, and insufficient fiber), and infections like human papillomavirus (HPV), which can lead to cancers of the cervix, anus, and throat.
Namrata Vijayvergia, MD, assistant chief of gastrointestinal medical oncology at Fox Chase Cancer Center, echoes the importance of lifestyle changes for cancer prevention.
“Avoid alcohol and smoking, be physically active, and try to maintain a healthy weight, too,” she advises. Dr. Vijayvergia adds that inactivity has become a modern-day equivalent to smoking in terms of cancer risk. “Studies like this further substantiate our efforts to make small changes for cancer prevention.”
The Impact of Modifiable Risk Factors: Over 250,000 Preventable Cancer Deaths
The study reveals that lifestyle-related factors are responsible for more than 700,000 new cancer cases annually in the U.S., as well as over 262,000 deaths. Cancer types with the highest number of cases linked to controllable risk factors include lung, colorectal, liver, and esophageal cancers.
Lung cancer, driven largely by smoking, accounted for 122,720 deaths, making it the deadliest cancer attributed to modifiable behaviors.
Despite efforts to reduce smoking rates, the number of lung cancer deaths remains alarming.
While smoking prevalence in the U.S. has decreased – 11% of adults reported smoking in 2022 compared to 15.6% in 2016 – the harmful effects of past smoking behavior still manifest in current lung cancer statistics.
“If you smoke, stop, and seek help with cessation programs,” advises Dr. Milana Dolezal, an oncologist at Stanford Medicine Cancer Center.
Early detection efforts, such as low-dose CT scans for smokers, have helped reduce deaths from lung cancer by identifying cancers at earlier stages. However, the most effective measure remains smoking cessation.
Healthcare Disparities and Cancer Prevention
Although individual lifestyle choices play a significant role in cancer prevention, not everyone has equal access to preventive healthcare or the resources needed to make healthier decisions. Healthcare disparities – stemming from differences in race, ethnicity, socioeconomic status, and access to care – can exacerbate cancer risks and outcomes for certain populations.
Dr. Dolezal highlights that along with modifiable risk factors, other elements such as age, genetic predisposition, and family history also influence cancer risk. However, addressing healthcare disparities and improving access to preventive care could help mitigate some of these risks.
The study’s senior author, senior vice president, surveillance and health equity science at the American Cancer Society, Ahmedin Jemal, DVM, PhD, also stresses the need for equitable access to healthcare: “These findings show there is a continued need to increase equitable access to preventive healthcare and awareness about preventive measures.”
Vaccination as a Preventive Measure
Vaccines play a critical role in cancer prevention, particularly for cancers caused by viral infections, Dr. Jemal emphasizes the importance of vaccines for the hepatitis B virus, which can lead to liver cancer, and HPV, which is linked to several cancers, including cervical and oropharyngeal cancers.
“Effective vaccines are available for the hepatitis B virus that causes liver cancer and HPV, which can cause several cancer types,” he says.
Receiving these vaccines at the recommended times can significantly lower the risk of developing cancers related to these viruses.
“Get the HPV vaccine if eligible and encourage teen–young adult vaccine prevention, as the HPV virus causes cervical and anal cancer,” says Dolezal.
For those at higher risk, particularly individuals of Asian descent who are more prone to hepatitis. Dr. Dolezal recommends testing for Hepatitis B and C to manage and prevent associated liver cancer.
Reducing Cancer Risk by Quitting Smoking
Even though smoking rates in the U.S. have decreased over the past few decades, the number of lung cancer deaths linked to smoking remains alarmingly high, says Dr. Islami. Smoking rates have dropped significantly, with only 11% of adults in 2022 identifying as current smokers, compared to 15.6% in 2016.
Dr. Dolezal advises smokers to quit and seek help through cessation programs. She explains, “Per the U.S. Preventive Services Task Force, we now use low-dose CT scans of the chest for individuals with a history of heavy smoking, helping detect lung cancers at earlier stages.”
In addition, former and current smokers are monitored in specialized “lung nodule clinics,” where any nodules found on CT scans are carefully observed. While nodule doesn’t necessarily indicated cancer, it can be an early sign. Detecting cancer early improves the likelihood of a successful treatment, so these clinics closely monitor any abnormalities.
While screening and surveillance have helped reduce lung cancer deaths, quitting smoking still remains the most effective way to lower lung cancer risk, says Dr. Dolezal. However, she also notes that not all lung cancers are caused by smoking, and there has been a troubling rise in lung cancer causes among women.
Addressing the Growing Cancer Burden: Weight and Alcohol
While smoking remains a leading preventable cause of cancer, the increasing incidence of cancers related to excess body weight is a growing concern. Cancers associated with obesity, such as colorectal, endometrial, and liver cancers, are becoming more common, especially among younger individuals. Maintaining a healthy body weight through regular exercise and a heart-healthy diet is crucial for reducing cancer risk.
Dr. Dolezal also addresses the risks associated with alcohol consumption, emphasizing moderation.
“That means no more than one drink at a sitting and no more than three in a week,” she advises. Experts increasingly argue that no amount of alcohol is completely safe, suggesting that minimizing or avoiding alcohol entirely may offer the best protection.
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