In the next two decades, the world could see a 60% increase in the number of cancer cases, according to a new report from the World Health Organization. In low- and middle-income countries, the increase could be as high as 81%, CNN says.

One in six people die from cancer every year, and the burden of cancer is increasing, WHO said in its 2020 World Cancer Report published this month. Around 9.6 million people died from cancer in 2018, the most recent year for which data is available.

But the increase in deaths is greater in poorer countries.

One reason for the inequality is the difference in the proportion of people exposed to cancer risk factors, the report finds. For example, low-income countries tend to have higher rates of cancers related to infection, such cervical cancer from HPV, than high-income countries.

Also, smoking rates are decreasing in high-income countries such as the United States, but not in low-income countries, according to research from the International Agency for Research on Cancer. Lung cancer, which is linked to tobacco use, remains one of the leading causes of cancer deaths globally.

Another reason might be differences in resources available, the report explains. For example, a larger proportion of the already limited health resources in poor countries are spent on conditions such as infectious disease instead of prevention, diagnosis and treatment of cancer.

By 2030, 7 million lives could be saved if governments invested about $3 per person in low-income countries, $4 in lower-middle-income countries and $8 in upper-middle-income countries in cancer resources, according to the report.