Cancer Rates Declining But Not in Developing Countries

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The incidence and mortality rates from several common forms of cancer have declined in recent years in many high-income countries (HIC), according to a study published in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research (AACR). Conversely, the same could not be said is true for low- and middle-income countries (LMIC).

Although, these high-income countries (HIC) still have the highest incidence rates including on lung, colorectal, breast, and prostate cancer, the death counts from these cancers have gone down thanks largely to the decline in known risk factors, screening, and early detection, and improved treatment, says the study, which was sponsored by the American Cancer Society.

Some of the LMICs have the highest rates of stomach, liver, esophageal, and cervical cancer and the mortality rates in LMICs are increasing for these cancers due to the rise in health risks.

"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 Lindsey A. Torre, MSPH, epidemiologist at the American Cancer Society and lead author of the study.

"In contrast, rates for cancers such as lung, breast, and colorectum are now rising in many LMICs due to increases in risk factors typical of Western countries, such as smoking, excess body weight, physical inactivity, and changing reproductive patterns," she added.

There were about 50 countries selected to represent various regions of the world for the study. The researchers took into account the incidence and mortality data from the International Agency for Research on Cancer (IARC) CancerMondial database for 2003-2007, which includes incidence data through 2007 from Cancer Incidence in Five Continents, a collaboration between the IARC and the International Association of Cancer Registries, and mortality data through 2012 from the WHO Cancer Mortality database, according to news release from the American Association for Cancer Research.

Torre said that the finding of the study did not come as a surprise to her anymore because they were already aware of the growing cancer trends in these low and middle-income countries for a few years. In 2012 alone, there was an estimate of about 14 million new cancer cases, NPR.org reported.

Researchers are still trying to figure out exactly why the cancer rates among LMICs are rising, Torre added that this could also be brought about by the growth and aging of the population in these countries. She surmised that as population booms and people tend to live longer, it also means they are living long enough to develop cancer.