Cancer is exhibiting opposite trends across the world as rates increase in low and middle-income countries and decrease in high-income countries.
Researchers from the American Cancer Society reviewed cancer incidence and mortality data collated by the International Agency for Research on Cancer (IARC) from 2003-2007. The researchers also included in their investigation WHO's Cancer Mortality database through the year 2012.
All in all, 50 countries were selected to depict rates from different regions around the world.
The researchers found that in 2012, approximately 14.1 new cancer cases and 8.2 million cancer deaths occurred.
The study focused on eight major types of cancer, which account for 60 percent of all cancer morbidity and mortality cases in the world.
Among the most prominent sets of findings is the difference between trends in high-income countries (HIC) and low and middle-income countries (LMIC).
Dip for HIC
The study found that HIC are still accountable for the highest incidence rates in all body parts, including breast, lung, prostate and colorectal cancers. Deaths from these cancers, however, are dropping in many HIC.
The numbers remain high for other cancers such as in the esophagus, stomach, liver and cervix, but it is showing a decreasing trend because of the elimination of risk factors and implementation of preventive measures, screening techniques and improved treatments.
"The rates of many cancers are being brought under control in Western countries through decreasing prevalence of known risk factors, early detection, and improved treatment," said study lead author Lindsey A. Torre.
Rise of the Big C in LMIC
Some LMIC can now be included in the list of nations with the highest incidence of breast, lung, prostate and colorectal cancers. Mortality rates for these types of cancers also show an increasing trend in LMIC.
Esophageal, stomach, liver and cervical cancers have the highest rates in LMIC. The numbers are growing because unlike HICs, which show improved risk factor management, LMICs exude rises in smoking, obesity and physical inactivity.
"Applied cancer control measures are needed to reduce rates in HICs and arrest the growing burden in LMICs," the authors wrote.
The study was published in the journal Cancer Epidemiology, Biomarkers & Prevention on Monday, Dec. 14.
Photo: José Eugenio Gómez Rodríguez | Flickr