The globe is facing a “tidal wave” of cancer, and restrictions on alcohol and sugar need to be considered, say World Health Organization scientists.
It predicts the number of cancer cases will reach 24 million a year by 2035, but half could be prevented.
The WHO said there was now a “real need” to focus on cancer prevention by tackling smoking, obesity and drinking.
The World Cancer Research Fund said there was an “alarming” level of naivety about diet’s role in cancer.
Fourteen million people a year are diagnosed with cancer, but that is predicted to increase to 19 million by 2025, 22 million by 2030 and 24 million by 2035.
The developing world will bear the brunt of the extra cases.
Dr Chris Wild, the director of the WHO’s International Agency for Research on Cancer, told the BBC: “The global cancer burden is increasing and quite markedly, due predominately to the ageing of the populations and population growth.
“If we look at the cost of treatment of cancers, it is spiralling out of control, even for the high-income countries. Prevention is absolutely critical and it’s been somewhat neglected.”