Up to 4 in 10 global cancer cases deemed preventable

A new study from the World Health Organization published in the journal Nature Medicine found that nearly 4 in 10 cancer cases worldwide could have been prevented with different lifestyle and health-focused choices.

According to the study, cancer is still a leading reason people are very ill or die, but it’s “largely attributable to modifiable risks.”

In an analysis of 2022 deaths, researchers found 30 risk factors that could be changed, including use of tobacco (including smokeless tobacco), alcohol use, high body mass, too little exercise, inadequate levels of breast feeding to boost infant immunity, air pollution, too much sun exposure, and nine infectious agents and 13 occupational risks.

The researchers used data from 36 cancer treatment centers in 185 countries and estimated that about 78.1 million of the new cancer cases diagnosed in 2022 could be attributed to those 30 modifiable risk factors, including nearly 30% of cancers in women and more than 45% of cancers in men.

Depending on the particular cancer, in women the rate that was preventable ranged from 24.6% to 38.2%, while for men the range was 28.1% to 57.2% of cancer cases that could have been avoided.

Smoking, infections and imbibing alcohol were the biggest reasons for cancer cases that need not have happened, per the study. And those contributed heavily to the lung, stomach and cervical cancers that made up almost half of the preventable cancer cases.

In a news release, the WHO reported that smoking and air pollution were key factors that contributed to lung cancer. Stomach cancer’s main preventable cause was infection from Helicobacter pylori. And most cases of cervical cancer were caused by human papillomavirus (HPV), for which a vaccine is widely available in the U.S.

“This is the first global analysis to show how much cancer risk comes from causes we can prevent,” Dr. André Ilbawi, the WHO team member in charge of cancer control and the study’s author, said in the release. “By examining patterns across countries and population groups, we can provide governments and individuals with more specific information to help prevent many cancer cases before they start.”

Differences by gender and region

The report showed differences across regions. In North Africa and West Asia, the preventable cancers in women were about 24% of cases, while in sub-Saharan Africa the share was 38%. Among men, the biggest preventable burden was found in East Asia, where the group said 57% of cases didn’t have to occur. For men, it was lowest in Latin America and the Caribbean, at 28%.

Prevention based on cancer type

The Siteman Cancer Center says there are 12 cancers where you can reduce risk of getting them by not embracing certain behaviors. For instance, bladder cancer risk can be reduced if workers avoid unprotected exposure to certain chemicals used to produce rubber and aluminum. Other examples of risk reduction include not smoking, and making sure drinking water has been tested for arsenic.

To reduce risk of breast cancer, those at high risk genetically are told to take prescription tamoxifen/raloxifene for at least five years. For those not at high risk, keeping weight in the normal range, not smoking, very moderate or no drinking, lots of fruit and vegetable consumption, physical activity and not using birth control pills or menopause hormone therapy reduce risk.

Many of those risk factors also influence risk of other cancers. For instance, smoking is implicated in increased risk of bladder cancer, breast cancer, cervical cancer, colon cancer, kidney cancer, lung cancer, pancreatic cancer, aggressive prostate cancer and stomach cancer.

Carrying excess pounds can contribute to higher risk of breast cancer, colon cancer, kidney cancer, ovarian cancer, pancreatic cancer, aggressive prostate cancer, stomach cancer and uterine cancer.

Alcohol at anything but low or no consumption levels can influence risk of developing breast cancer, colon cancer, kidney cancer and stomach cancer.