Nearly half of all U.S. cancer deaths may be preventable

Some 40 percent of cancers and nearly half of all deaths from the disease in adults ages 30 and older are tied to risk factors that people can control—smoking, drinking alcohol, obesity, physical inactivity, and vaccine-preventable infections, according to a new study lead by researchers at the American Cancer Society (ACS).

When it comes to cancer, there are some things that increase people’s risk for the disease that they can’t do anything about. For example, the risk for cancer increases with age. Having certain genetic mutations or a family history of the disease can also make some people more likely to get cancer than someone else.

For this study, published on July 11 in CA: A Cancer Journal for Clinicians, the researchers estimated the proportion and number of cases and deaths for 30 cancer types that could be tied to modifiable risk factors—or things that people can change. These risk factors included:

• Smoking cigarettes
• Exposure to secondhand smoke
• Having excess body weight
• Drinking alcohol
• Eating red and processed meat
• Eating a low-fiber, low-calcium diet that lacks fruits and vegetables
• Being inactive or sedentary
• Exposure to ultraviolet (UV) radiation
• Infections, including hepatitis B virus (HBV) and human papillomavirus (HPV)

The study included nationally representative data on 713, 340 cancer cases and 262,120 cancer deaths that occurred in 2019. It showed that among adults as young as 30, four in 10 cancers and about one half of all deaths were linked to these modifiable factors.

The most notable risk: smoking. The researchers found that overall, smoking cigarettes contributed to almost 20 percent of cancer cases and 30 percent of all cancer deaths.

“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,” said the study’s lead author, Farhad Islami, MD, PhD, senior scientific director, cancer disparity research at the ACS in a news release. “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.”

Excess body weight accounted for the second largest proportion of cancer cases, or 7.6 percent of potentially preventable cases. It was linked to about 5 percent of new cases in men and nearly 11 percent of cases in women. Excess weight was also tied with more than 30 percent of deaths from cancer of the uterus, gallbladder, esophagus, liver, and kidney, the study found.

“Interventions to help maintain healthy body weight and diet can also substantially reduce the number of cancer cases and deaths in the country, especially given the increasing incidence of several cancer types associated with excess body weight, particularly in younger individuals,” said Dr. Islami.

Rounding out the top five modifiable risk factors:

• Alcohol consumption: 5.4 percent
• Exposure to UV radiation: 4.6 percent
• Physical inactivity: 3.1 percent

The study found that in 2019, alcohol consumption was linked to about 95 cancer cases and 24,000 cancer deaths. Alcohol was also associated with seven different types of cancer, including oral cavity, pharynx, larynx, colorectal, and breast. These findings support a landmark study published in 2018, which found that even one alcoholic drink per day could increase the risk for injuries and certain diseases, including several forms of cancer.

Next, when looking at specific types of cancer, some were more likely than others to be attributable to modifiable risk factors. For 19 out of 30 cancer types, the proportion of cases caused by potentially modifiable risk factors was greater than 50 percent. And for 10 types of cancer, controllable risk factors could be tied to at least 80 percent of new cases.

For example, the researchers found that nearly all cervical cancer cases were tied to HPV infection, which can be prevented with a vaccine. And more than 90 percent of melanoma cases were linked to exposure to UV radiation.

For both men and women, lung cancer had the largest number of cases attributable to controllable risk factors—more than 104,410 cases among men and 97,250 among women. This was followed by skin melanoma, colorectal cancer, and bladder cancer among men. And it was followed by breast, uterus, and colorectal cancer among women.

“These findings show there is a continued need to increase equitable access to preventive health care and awareness about preventive measures,” said the study’s senior author, Ahmedin Jemal, PhD, DVM, senior vice president, surveillance and health equity science at the American Cancer Society.