Lifestyle factors are the most important cause of cancer, say scientists.
Bernard Stewart, professor of oncology at the University of New South Wales, said: "Measures known to prevent cancer include smoking cessation, reducing alcohol intake, curbing obesity and avoiding deliberate sun exposure."
"Diverting attention from these messages threatens to undermine their efficacy to deliver proven benefits," added Stewart, who systematically reviewed medical literature on known and suspected cancer hazards, the journal The Lancet Oncology reported.
While there is evidence that air pollution contributes to cancer risk, "the risk is at least 10 times less than it is for smoking", a university statement quoted Stewart as saying.
"Though exposure to very small amounts of carcinogenic (cancer-causing) chemicals occurs as a result of food contamination and by using certain consumer products, these circumstances have never been shown to cause cancer in developed countries," he said.
"Cancer has not been shown to have arisen because regulatory authorities overseeing food standards or consumer product safety overlooked the evidence, with the possible exception of quicker action to ban tanning devices," Stewart said.