Global cancer cases could soar by 50% to 15m by 2020, experts predict - but a third could be prevented by healthy lifestyles.
Smoking is linked to a large number of cancers
The growth in cancer cases will largely be explained by the fact the population is steadily ageing.
But smoking is highlighted as a major cause of cancers, along with poor diets and lack of exercise, according to the World Cancer Report, published by the World Health Organisation.
The number of people dying from cancer is predicted to grow from 6.2m to 10m over the period.
But better screening and greater awareness of early symptoms and treatment developments should help cut death rates.
Most common cancers diagnosed - UK
Breast - 15%
Lung - 15%
Large bowel - 13%
Prostate - 9%
Bladder - 5%
In 2000, 12% of the 56m deaths around the world from all causes were due to cancer.
In some countries, more than a quarter of deaths were from cancer.
Three areas are key to reducing the incidence of cancer, the WHO said:
Reducing the numbers who smoke,
- Living a healthy lifestyle, including eating more fruit and vegetables and doing more exercise,
- Increasing early detection of cancers, such as cervical and breast, through screening.
The WHO is working to cut tobacco consumption and improve diet, nutrition and physical activity.
Bernard Stewart, a cancer specialist from the University of New South Wales, Australia, who co-wrote the report, said politicians and medics could do more to get healthy living messages across.
"Governments, physicians and health educators at all levels could do much more to help people change their behaviour to avoid preventable cancers."
Dr Rafael Bengoa, director of the management of non-communicable diseases at the WHO, said action was also needed to curb infections which can cause around 40% of cancers.
Most common causes of cancer deaths - UK
Lung - 22%
Large bowel - 10%
Breast - 8%
Prostate - 6%
Oesophagus - 5%
But he said the information scientists and doctors needed to tackle cancer was available now.
"We don't need new science. If the knowledge, technology and control strategies outlined in the World Cancer Report were applied globally, we would make major advances in preventing and treating cancers over the next 20 years and beyond."
Dr Gro Harlem Bruntland, director-general of the WHO, said: "The report provides a basis for public health action and assists us in our goal to reduce the morbidity and mortality from cancer, and to improve the quality of life of cancer patients and their families everywhere in the world."
Nicola O'Connor, science information manager for Cancer Research UK told BBC News Online: "You have to factor in the ageing population and cancer is a disease of old age."
She said smoking habits would have a significant impact on cancer trends in the next century, with the number of young people who take up smoking now influencing mortality rates in the mid to late 21st century.
Nine out of 10 lung cancers are linked to smoking.
Obesity has also been identified as a significant risk factor for cancers.
She said more research into cancer was needed.
"We do need new science. You can work on prevention and do all this work to get people to change their lifestyle, but that's a very difficult thing to do.
"At the same time, we need more research.
"There are all sorts of new treatments coming through in the pipeline from the laboratory that's improving knowledge and being tested in the clinics."