The global burden of cancer has hit poorer countries harder over the past 20 years, according to new report published on 2 June in the Journal of the American Medical Association. This "cancer divide" between rich and poor countries could be exacerbated in coming years.
The Global Burden of Disease study is designed to assess the prevalence of and mortality from 29 types of cancer across 195 countries or territories around the world. The current report focuses on the disease burden from cancer from 2000 to 2016 (JAMA, 2 June 2018).
Researchers found that there were 17.2 million cases of cancer and 8.9 million cancer deaths globally in 2016. The odds of developing cancer over an average lifetime of 0 to 79 years ranged from 1 in 3 for men to 1 in 5 for women; however, these odds varied greatly in different countries based on where they were in the sociodemographic index, a measure that incorporates fertility, education, and incomes.
Five types of cancers -- tracheal, bronchus, lung, colorectal, and prostate -- accounted for 40% of all cancer incidence in men. For women, breast, colorectal, and nonmelanoma skin cancers accounted for 40% of cancer incidence. Incidence and deaths for the top five cancers in men and women are as follows:
| Global incidence and deaths by cancer type, 2016 | ||
| Cancer type | Incidence | Deaths |
| Men | ||
| Tracheal, bronchus, and lung | 1.369 million | 1.117 million |
| Liver | 736,000 | 590,000 |
| Stomach | 766,000 | 536,000 |
| Colon and rectum | 952,000 | 450,000 |
| Prostate | 1.436 million | 381,000 |
| Women | ||
| Breast | 1.682 million | 535,000 |
| Tracheal, bronchus, and lung | 638,000 | 530,000 |
| Colon and rectum | 763,000 | 380,000 |
| Stomach | 391,000 | 298,000 |
| Cervical | 511,000 | 247,000 |
But the researchers also found disparities among nations. For example, between 2006 and 2016, the incidence rate of all cancers combined grew in 130 of 195 countries. But death rates fell in 143 out of 195 countries; most of the nations with higher death rates were in the lowest 20% of the sociodemographic index and were primarily in Africa and the Middle East.
The report authors also noted that longer life expectancy and population growth are leading to higher rates of cancer incidence, although incidence rates for cancers such as tracheal, bronchus, and lung are falling in wealthier countries due to the success of tobacco control efforts. They recommended that tobacco control efforts focus on poorer countries so these nations won't have to experience "the same tragedy of unnecessary tobacco-related deaths" that wealthier countries experienced.
