Low and middle income countries are now facing rising numbers of breast, colorectal and other common cancers, finds a new study, due in part to increases in obesity, inactivity and smoking around the world. The United States and other high-income countries continue to have the highest cancer rates, but rates have stabilized here.
The study, published today in Cancer Epidemiology Biomarkers and Prevention, shows a disturbing trend around the world, where many countries have adopted a lifestyle once attributed primarily to the US and other Western countries. AICR estimates that here in the US, about one-third of cancers are preventable if everyone was to be a healthy weight, be active and eat a healthy diet.
Using estimates from the International Agency for Cancer Research and other registries, the study pulled together incidence and mortality for several common cancers around the world. Among the findings described are:
Breast cancer is the leading cause of cancer-related death among women worldwide. Incidence increased by about 30 percent in western countries between 1980 and the late 1990s, then these slowed or plateaued since the early 2000s. In Brazil, Uganda and other low to middle-income countries, rates of this cancer continue to increase. The causes of these increases are not completely understood.
Colorectal cancers – Rates of colorectal cancers are increasing in many countries where they were historically low, such as in Latin America and Asia. Incidence is also increasing in Eastern Europe. Here in the US., rates are lowering overall, thanks largely to screening. Yet in the US and Australia, colorectal cancers are increasing among people younger than 50.
Prostate cancer is the second most frequently diagnosed cancer among men worldwide. Black men in the US have the highest incidence, followed by men in France and Australia. The highest mortality rates are in Trinidad and Tobago, followed by US blacks.
Esophageal cancers – Northern Iran, Central Asia and north-central China all have relatively high incidence of a common type of esophageal cancer, called squamous cell carcinoma. Africa also has some of the highest incidence. Behaviors thought to increase the risk in these areas include poor nutrition, low intake of fruits and vegetables, and drinking beverages at extremely high temperatures.
Rates of this type of esophageal cancer is decreasing in North America and Europe, with fewer people drinking alcohol and smoking. But for the other main type of this cancer (adenocarcinoma) rates are increasing in the US and other Western countries, likely due to obesity.
All cancers – In 2012, when the most recent data was available, there was an estimated 14.1 million cases of cancer worldwide. By 2030 that number is expected to rise to almost 22 million cases, based solely on population growth and age. This study suggests the growing numbers may make that figure even higher.
As the authors conclude: “A large proportion of cancers can be prevented through measures including tobacco control, vaccination, early detection, and promotion of healthy lifestyles.”
The study was funded by the Intramural Research program of the American Cancer Society,
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