Earlier this week, as part of a series on the global burden of disease (GBD), the Institute for Health Metrics and Evaluation (IHME) released its report specifically looking at cancer in JAMA Oncology. Tracking changes from 1990 to 2013 in 188 countries, the report found that cancer has now jumped from the third to the second leading cause of death, right behind cardiovascular disease. Largely across the board, the number of new cancer cases and deaths has steadily increased, with 14.9 million new cases and 8.2 million deaths estimated in 2013.
Measuring the loss of productivity and health in years, the report additionally found that a whopping 196.3 million disability-adjusted life-years (DALYs) were lost to the aether in 2013. While the conclusions are sobering, the authors feel there are lessons to be learned and even some good news on the horizon from them.
Global measures of cancer rates have existed for some time, largely based on the collection of data from cancer registries from across the world. But IHME researchers, fearing that these registries, particularly in low-to-middle income countries, would not be able to capture the entire scope, turned to additional sources when calculating the death toll. “In brief, all published and unpublished data relevant to estimating causes of death for 188 countries from 1980 to 2013 were identified. The sources include vital registration systems, verbal autopsy studies, and other sources,” they wrote.
Out of the 28 cancers they studied, they found that, together, tracheal, bronchus, and lung cancers were the biggest killers, with 1.6 million deaths in 2013. Splitting down by gender, breast cancer was the most likely and hardest burden on women, with 1.8 million new cases, 13.1 million years in DALYs lost, and 464,000 deaths in 2013. But overall, cancer hit men hardest, with one in three developing cancer between birth and age 79, while the same was true of one in five women.
The authors note the rise in cancer can largely be tied to an aging and growing population, but it is also a trend that is beginning to engulf developing nations every bit as much as their developed counterparts. Developing countries are experiencing faster population and life expectancy growth, but without the health care infrastructure of more stable countries, leading to higher death tolls than might be seen in the United States or other western nations.
That disparity can perhaps be best seen in the incidence of cervical cancer, which, relative to other cancers, has only slightly increased between 1990 to 2013. And when accounting for age and population, cervical cancer rates have actually dropped, which is in no small part due to the available vaccine against human papilloma virus (HPV), a potential cause of the cancer. But these rates are particularly profound among wealthy regions with extensive screening programs, with rates three times lower than among those without screening programs. As vaccination and screening programs reach more parts of the world, cervical cancer rates will fall with them, the authors conclude.