Cancer incidence and mortality rates are increasing in low- and middle-income countries, perhaps due to lifestyle changes and lack of appropriate screening or prevention measures, according to a new study published in Cancer Epidemiology, Biomarkers and Prevention, a journal of the American Association for Cancer Research (AACR).
Lindsey Torre and colleagues from the American Cancer Society used the most recent data from the Cancer Incidence in Five Continents (CI5) project, a collaboration between the International Agency for Research on Cancer and the International Association of Cancer Registries. The data included 290 registries representing more than 400 populations (Cancer Epidemiol Biomarkers Prev, December 14, 2015).
Around the world, an estimated 14.1 million new cancer cases and 8.2 million cancer deaths occurred in 2012, the group found. Eight major kinds of cancer account for 60% of the total global cases and deaths: breast, prostate, colorectal, lung, esophageal, stomach, liver, and cervical cancer.
Incidence and mortality rates for many of these cancers have decreased in high-income countries but increased in low- and middle-income countries. The researchers also noted the following:
- Prostate cancer is the most commonly diagnosed cancer among men in 87 countries, especially in North and South America.
- Breast cancer is the most common in North America, Europe, and Oceania.
- Lung cancer is the most commonly diagnosed cancer among men in Eastern Europe.
- In Africa, the leading cancers among men are prostate cancer, lung cancer, colorectal cancer, liver cancer, esophageal cancer, Kaposi's sarcoma, leukemia, stomach cancer, and non-Hodgkin's lymphoma.
- In Asia, the leading cancers among men are lung, lip and oral cavity, liver, stomach, colorectal, and prostate cancer.
|Global cancer incidence rates by disease type|
|Cancer type||New cases diagnosed in 2012||Highest incidence, men (cases per 100,000)||Highest incidence, women (cases per 100,000)|
|Lung and bronchus||1.8 million||90, Turkey||38, U.S.|
|Colon and rectum||1.4 million||62, Japan||37, Japan|
|Breast cancer||1.7 million||--||103, Switzerland|
|Stomach||951,600||67, Japan||25, Republic of Korea|
|Liver||--||41, Republic of Korea||14, Africa|
The increase in the incidence of cancers in low- and middle-income countries is a serious concern, the authors wrote.
"Rates for cancers commonly found in high-income countries, such as lung, breast, and colorectum, are now rising in many low- and middle-income countries due to increases in risk factors typical of Western countries, such as smoking, excess body weight, physical inactivity, and changing reproductive patterns," the group concluded. "Moreover, these countries continue to bear a disproportionate burden of infection-related cancers, including stomach, liver, and cervix."