Fewer people are dying from cancer in wealthy countries, while mortality rates are on the rise in lower-income countries, a new study says, providing fresh evidence that lifestyle weighs heavily in cancer rates, as does access to quality medical care.
Writing in the journal Cancer Epidemiology, Biomarkers & Prevention, researchers said the prevalence of cancer in high-income countries has waned or plateaued, and the death rate fallen, thanks to improved screening, early detection, aggressive treatment and a reduction in risky behavior such as smoking.
In low- and middle-income countries that increasingly embrace Western habits, however, mortality is increasing, and these countries now see the highest rates of stomach, liver, esophageal and cervical cancer. The researchers attribute this to an increase in smoking and obesity, as well as increasingly sedentary lifestyles enabled by a decline in manual labor.
Authors Lindsey Torre, Rebecca Siegel, Elizabeth Ward and Ahmedin Jemal studied cancer incidence and mortality in 50 countries from 2003 to 2007. Some of their findings are startling. The incidence of cervical cancer, for example, has declined by 70 percent overall in recent years, yet it is increasing in countries like Zimbabwe and Uganda, where fewer women have access to screenings that would detect the cancer in its earliest stages.
Low- to moderate-income countries have the highest rates of four types of cancer stomach, liver, esophageal and cervical with the greatest incidence in Africa, South America and Asia. Some of the increase is attributable to cancers caused by infection. For example, hepatitis is believed to cause 70 percent to 90 percent of cancers of the liver. But rates of lung, breast and colorectal cancer are also on the rise, even as they decline in wealthier countries.
The findings coincide with another new report from the Stony Brook Cancer Center in New York. Published by the journal Nature Dec. 16, it said 70 percent to 90 percent of cancers can be attributed to lifestyle triggers, such as obesity, exposure and tobacco use, that cause cancer cells to develop and spread. Cancer risk is heavily influenced by extrinsic factors, the researchers wrote.
While healthy habits like not smoking, keeping a healthy weight, eating a healthy diet and cutting back on alcohol are not a guarantee against cancer, they do dramatically reduce the risk of developing the disease, Dr. Emma Smith of Cancer Research UK told the BBC.
Both studies seem to refute a controversial report from earlier this year, in which researchers from Johns Hopkins University in Baltimore concluded that random errors of DNA are the major cause of cancer, making its incidence more attributable to bad luck than poor lifestyle choices.
Writing in the journal Cancer Epidemiology, Biomarkers & Prevention, researchers said the prevalence of cancer in high-income countries has waned or plateaued, and the death rate fallen, thanks to improved screening, early detection, aggressive treatment and a reduction in risky behavior such as smoking.
In low- and middle-income countries that increasingly embrace Western habits, however, mortality is increasing, and these countries now see the highest rates of stomach, liver, esophageal and cervical cancer. The researchers attribute this to an increase in smoking and obesity, as well as increasingly sedentary lifestyles enabled by a decline in manual labor.
Authors Lindsey Torre, Rebecca Siegel, Elizabeth Ward and Ahmedin Jemal studied cancer incidence and mortality in 50 countries from 2003 to 2007. Some of their findings are startling. The incidence of cervical cancer, for example, has declined by 70 percent overall in recent years, yet it is increasing in countries like Zimbabwe and Uganda, where fewer women have access to screenings that would detect the cancer in its earliest stages.
Low- to moderate-income countries have the highest rates of four types of cancer stomach, liver, esophageal and cervical with the greatest incidence in Africa, South America and Asia. Some of the increase is attributable to cancers caused by infection. For example, hepatitis is believed to cause 70 percent to 90 percent of cancers of the liver. But rates of lung, breast and colorectal cancer are also on the rise, even as they decline in wealthier countries.
The findings coincide with another new report from the Stony Brook Cancer Center in New York. Published by the journal Nature Dec. 16, it said 70 percent to 90 percent of cancers can be attributed to lifestyle triggers, such as obesity, exposure and tobacco use, that cause cancer cells to develop and spread. Cancer risk is heavily influenced by extrinsic factors, the researchers wrote.
While healthy habits like not smoking, keeping a healthy weight, eating a healthy diet and cutting back on alcohol are not a guarantee against cancer, they do dramatically reduce the risk of developing the disease, Dr. Emma Smith of Cancer Research UK told the BBC.
Both studies seem to refute a controversial report from earlier this year, in which researchers from Johns Hopkins University in Baltimore concluded that random errors of DNA are the major cause of cancer, making its incidence more attributable to bad luck than poor lifestyle choices.
