Most US Adults Unaware of Two Major Cancer Risk Factors

First National Online Survey of Its Type

Kristin Jenkins

October 24, 2017

The majority of adults in the United States are still in the dark about alcohol and obesity being major lifestyle-related risk factors for cancer, the first national online cancer survey reveals.

Results from the National Cancer Opinion Survey, undertaken by the American Society of Clinical Oncology (ASCO) in collaboration with the Harris Poll, indicate that 89% of adults are optimistic about the future of cancer research, prevention, and treatment and actively take steps to prevent cancer. These actions include not smoking (66%) and eating fruits and vegetables (50%). Most understand cancer risk factors, such as tobacco use (78%) and sun exposure (66%).

However,  only 31% realized that a high body mass index increases the risk for cancer (colon, breast, high-grade prostate, and uterine cancers). Furthermore,  only 30% recognized that drinking alcohol raises risk (for esophageal, breast, and colon cancers).

Additionally, 80% were unaware of the role of viruses in increasing cancer risk.

The findings were published online on the ASCO website on October 24. 

Notably, more than a third of the survey participants had experienced cancer themselves (4%) or have a family history of cancer (32%).

While those with some personal experience were more likely to take preventive measures against disease, these actions most often consisted of reducing sun exposure and increasing vitamin intake, the survey shows. Only 41% said they maintained a healthy weight to prevent cancer, and 38% said they limit alcohol consumption. More than half of adults said they didn't use sun block.

"This research 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," said Bruce Johnson, MD, president of ASCO, in a statement.

"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," he added.

The survey was conducted online between July 10 and 18 and  included a nationally representative sample of 4016 adults aged 18 years and older.

These data should act as a "wake-up call," particularly in light of the obesity epidemic, said Richard Schilsky, MD, chief medical officer of ASCO. "Our lifestyles have a big impact on our risk of developing many common cancers."

More than a third of Americans are obese, and obesity is a major factor in the growing cancer burden in the United States, he pointed out, emphasizing that the situation is urgent. "We can't allow obesity to undo the advances we've made in cancer prevention, early diagnosis, and treatment," Dr Schilsky  told Medscape Medical News.

The National Cancer Institute predicts that by 2030, at current rates of increased obesity, there could be 500,000 more cases of obesity-related cancer in the United States.

ASCO will continue to investigate evidence-based solutions, provide education resources, and share information on obesity and cancer through medical meetings and other channels, said Dr Schilsky. For now, the annual survey will improve understanding of the public's perception of cancer research and care.

Dr Schilsky also pointed out that no single organization or medical specialty can address the problem of overweight alone.

To address the cancer risks associated with alcohol consumption, ASCO will release a statement next month outlining several public health strategies. Even modest alcohol use can increase cancer risk, but the greatest risks are seen in people with a history of "heavy, long-term use," Dr Schilsky noted.

"It's critical for Americans to understand the link between alcohol and cancer so they can make more informed choices," he summarized.

In the survey, 91% of respondents said the US government should dedicate substantial funding to diagnose, prevent, and treat cancer. Most also said the federal government should lower the cost of prescription drugs, with 92% believing that Medicare should negotiate drug prices directly with pharmaceutical manufacturers, 86% indicating that the cost of cancer drugs should be lowered through government regulation, and 80% agreeing that it should be legal to buy cancer drugs outside the United States.

Dr Schilsky has received institutional research funding from AstraZeneca, Bayer, Bristol-Myers Squibb, Genentech/Roche, Lilly, Merck, and Pfizer.

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