Many Americans have fatalistic beliefs about cancer, and they may be less likely to take steps to lower their risk, a new study suggests.

The National Cancer Institute's survey of more than 6,000 people found 47 per cent agreed that "nearly everything causes cancer," while 27 per cent agreed that "There's not much people can do to lower their chances of getting cancer."

"Many Americans seem to feel afraid and helpless in regards to cancer, which may be exacerbated by conflicting news reports and a general lack of education on the causes and prevention of cancer," said population health Prof. Jeff Niederdeppe of the University of Wisconsin, Madison.

"They say, 'Well, there is nothing much you can do about it' and, as our survey shows, they indeed do nothing about it."

Nearly 72 per cent of American adults agreed that "There are so many recommendations about preventing cancer, it's hard to know which ones to follow."

People who agreed with a least one of the three statements were less likely to exercise weekly and eat five servings of fruits and vegetables a day — simple steps people can take to reduce their risk.

"Americans who hold fatalistic beliefs about cancer prevention may be at greater risk of cancer because they are less likely to engage in various prevention behaviours," the study's authors concluded in the May issue of the journal Cancer Epidemiology, Biomarkers & Prevention.

"Results have notable implications for future cancer communication and education efforts."

Overall, people who were less educated were more likely to hold the beliefs.

The researchers suggested educators could focus on developing simple messages on preventing disease.