The number of new cases of cancer in the world is rising, according to a new report that looked at cancer in 118 countries.
Globally, the number of new cancer cases increased from 8.5 million in 1990 to 14.9 million in 2013, the study found. (The world population rose from 5.3 billion to 7.1 billion during that time.)
In addition, cancer is accounting for an increasingly greater proportion of deaths: In 1990, 12 percent of all deaths in the countries studied were due to cancer, but in 2013, it was 15 percent.
The researchers specifically looked at 28 different types of cancer, and found that cases from nearly all of these types of cancer have increased in the last two decades — ranging from a 9 percent increase in cervical cancer cases to a 217 percent increase in prostate cancer cases. The only cancer that decreased during the study period was Hodgkin's lymphoma, which saw a 10 percent decrease in the number of new cases between 1990 and 2013.
The overall rise in cancer cases is partly due to longer life spans, since the risk of cancer increases with age. "With life expectancy increasing globally, the future burden of cancer will likely increase," the researchers said. The growing global population, increases in obesity and poor dietary habits also have contributed to the rise, they said. [10 Do's and Don'ts to Reduce Your Risk of Cancer]
Cancer is more common in men than in women, with 1 in 3 men worldwide developing cancer before age 79, compared with 1 in 5 women.
The most common cancer overall was cancer of the lungs, trachea or bronchus, with 1.8 million new cases and 1.6 million deaths in 2013, followed by breast cancer and colon cancer. The most common cancer in men was prostate cancer, and the most common cancer in women was breast cancer.
A particularly concerning trend is an increase in cancer cases in developing countries, the researchers said. In 2013, the rates of new cancer cases were higher in developing countries than in developed countries for stomach cancer, liver cancer, esophageal cancer, cervical cancer, mouth cancer, and nose and throat cancer.
Lost years of healthy life due to cancer also increased 40 percent in developing countries between 1990 and 2013, compared to 10 percent in developed countries.
"Cancer has long been regarded as a problem of economically developed countries, with the reasoning that cancer burden is substantially higher in affluent countries and that cancer care requires too many resources and is too complex to provide in less developed countries," the researchers said.
The recent rise in cancer cases in developing countries is partly due to an increase in life expectancy and an increase in other risk factors for cancer, such as obesity and smoking. Developing countries have made advances in reducing deaths from infectious diseases, but to avoid an epidemic of noncontagious diseases, "cancer prevention efforts must be a priority," the researchers said.
The study findings are based on data from cancer registries, vital records, autopsy reports and other sources of information about causes of death. However, the researchers noted that registry and vital record data are sparse in many countries, which meant the researches needed to use other methods to estimate the cancer burden, which could affect the results.
The study is published online today (May 28) in the journal JAMA Oncology.
Another recent study that looked at cancer cases in 60 countries found that, although the total number of cancer cases is increasing, the rate of cancer deaths worldwide has declined in the last decade.