Rates of breast and lung cancer have doubled worldwide since 1975, according to a new report.
The increase is largely a reflection of population growth and longer lifespans, say the authors from Cancer Research UK.
More than 1.1 million cases of breast cancer are now diagnosed across the world each year. This compared with about 500,000 cases in 1975, said the researchers who analysed a global database of 27 cancers.
Most of the increase could be explained by the increased life expectancy of women worldwide, together with the world's burgeoning population. Since 1975, the world's population has grown from around four billion to an estimated 6.3 billion.
Lung cancer is now the most commonly diagnosed cancer in the world, with around 1.4 million new cases being identified each year. Fewer than 600,000 cases were diagnosed in 1975.
The vast majority of lung cancers are thought to be related to smoking. Lung cancer rates are therefore closely tied to the number of people who smoke, which is also affected by population size.
Incidence of the disease tends to peak around 20 years after the proportion of people smoking peaks.
Rates of stomach cancer, the most common type of cancer in 1975, are falling due to improved home hygiene and food preservation.
AP