Do You Know the Risk Factors for Cancer? Many Americans Don't

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Many Americans have misconceptions about risk factors for cancer, according to a new survey.

For the survey, called the National Cancer Opinion Survey, more than 4,000 U.S. adults answered questions to gauge their knowledge about risk factors for cancer. (The group of survey participants was representative of Americans, meaning the sample included the same proportions of people of different demographics and other characteristics as the country as a whole.)

Some risk factors were correctly identified by most survey participants. For example, nearly 80 percent correctly identified tobacco use as a risk factor for cancer, and 66 percent correctly identified sun exposure as a risk factor for cancer.

However, only 31 percent were aware that obesity is a risk factor for cancer. This is worrisome, the researchers said, because obesity is the second-leading preventable cause of cancer (behind tobacco use). Studies have linked obesity with an increased risk of colon, breast, prostate and uterine cancers.

"That so few Americans are aware that maintaining a healthy weight is associated with lower risk for many cancers should serve as a wake-up call," said Dr. Richard Schilsky, chief medical officer at the American Society of Clinical Oncology (ASCO). ASCO commissioned the survey, which was carried out by Harris Poll in July 2017. "Unfortunately, obesity is a problem that cannot be solved overnight and will require broad societal engagement to address," he said in a statement. [10 Do's and Don'ts to Reduce Your Risk of Cancer]

The survey also found that only 30 percent of Americans know that drinking alcohol is a risk factor for cancer. Studies have found that alcohol consumption can increase the risk of mouth, liver and breast cancers, the researchers said.

In addition, only 25 percent of Americans know that a lack of exercise can increase the risk of cancer. A recent study, for instance, found that exercise is linked with a lower risk of 13 types of cancer.

What's more, some Americans falsely believed that certain factors could increase their cancer risk: 14 percent said they thought cellphones could increase the risk of cancer, and 8 percent said they thought caffeine consumption could increase the risk of cancer. (ASCO does not recognize cellphones or caffeine as risk factors for cancer. Many studies have found no link between cellphone use and cancer. In addition, many studies have found that caffeine consumption is actually linked with a lower risk of cancer.)

The survey also found that many Americans are not taking some important steps that can reduce their risk of cancer. Less than half (48 percent) said they use sunblock or limit their sun exposure, and only 38 percent said they limited alcohol consumption.

Still, the majority of Americans (66 percent) said they do not smoke, and 50 percent said they eat lots of fruits and vegetables. Both factors can lower a person's risk of cancer.

Participants were also asked questions about their personal experience with cancer. Concerningly, some Americans who have cancer said they have taken dangerous steps to cut their treatment costs, which could be harmful to their health, the researchers said. About one-quarter of the participants who said that either they or a family member has or has had cancer said they had taken steps to reduce treatment costs. For example, 9 percent said they had skipped doctor appointments, 8 percent said they had refused treatment, 8 percent said they had postponed filling or had not filled prescriptions, 8 percent said they had skipped doses of prescribed medications and 7 percent said they had cut pills in half.

It's alarming "that Americans are potentially risking not only their health but also their lives due to high treatment costs," Schilsky said. Patients should not have to make an "impossible choice" between their cancer treatment and other necessary expenses, he said.

Most of the survey participants also said they believed that the federal government should take action to lower the cost of prescription drugs.

Overall, the survey "helps us understand what our fellow Americans know and believe about cancer, and therefore where we need to focus as a nation in our efforts to conquer cancer," ASCO President Dr. Bruce Johnson said. "It is clear there are many important gaps we need to address — from educating the public about cancer prevention to confronting high treatment costs, to investing in cancer research that is vital to improving patients' outcomes in the future," Johnson said.

Original article on Live Science.

Rachael Rettner

Rachael is a Live Science contributor, and was a former channel editor and senior writer for Live Science between 2010 and 2022. She has a master's degree in journalism from New York University's Science, Health and Environmental Reporting Program. She also holds a B.S. in molecular biology and an M.S. in biology from the University of California, San Diego. Her work has appeared in Scienceline, The Washington Post and Scientific American.