(NAPSI)–The majority of Americans are unaware of several major risk factors for cancer—most notably obesity, which will soon overtake smoking as the largest preventable cause of cancer in the United States. This is one of the many findings from the American Society of Clinical Oncology (ASCO)’s National Cancer Opinion Survey.

Less than a third of Americans (31 percent) realize that obesity is a risk factor for cancer, even though it is currently the second leading preventable cause of the disease. In fact, a higher body mass index is associated with increased risk of a number of cancers, including colon, breast, high-grade prostate, and uterine cancers. According to a recent analysis by the National Cancer Institute, if the current rates of obesity continue to trend upward, by 2030 there could be about 500,000 additional cases of cancer in the United States than would otherwise be expected.

“Our lifestyles have a big impact on our risk of developing many common cancers,” said ASCO Chief Medical Officer Richard Schilsky, M.D., FACP, FASCO. “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. Unfortunately, obesity is a problem that cannot be solved overnight and will require broad societal engagement to address.”

The survey also found that few Americans are aware of other lifestyle factors that increase their cancer risk. For example, less than one in three Americans (30 percent) recognize alcohol as a risk factor for cancer, despite the fact that alcohol consumption can raise the risk of certain cancers, including cancers of the mouth, liver and breast. By contrast, a majority of Americans correctly identify tobacco use (78 percent) and sun exposure (66 percent) as risk factors for cancer.

In addition, some misperceptions about cancer risk persist: Fourteen percent of Americans incorrectly identify cell phones as increasing the risk of cancer, and 8 percent incorrectly identify caffeine as a risk factor for cancer.

At the same time, the majority of Americans are not taking some important preventive actions to reduce their cancer risk. Only 48 percent say they use sunblock or limit their exposure to the sun; 41 percent say they maintain a healthy weight; and 38 percent say they limit alcohol consumption in order to prevent cancer.

The nationally representative survey on Americans’ attitudes about cancer was commissioned by ASCO and conducted online by Harris Poll from July 10−18, 2017, among 4,016 U.S. adults ages 18 and older.

“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 ASCO President Bruce Johnson, M.D., FASCO. “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.”

The survey also shows that overall, Americans are optimistic about the future of cancer treatment and expect there to be a steady pace of progress over the coming decades. Nearly four in five Americans (79 percent) believe that the majority of cancers will be curable within the next 50 years, compared to 66 percent who think most cancers will be curable within the next 25 years, and 39 percent who believe most cancers will be curable within the next 10 years.

Further information is availableat www.asco.org/research-progress/reports-studies/national-cancer-opinion-survey.