Tobacco causes more cancer deaths that could have been avoided than any other risk factor. Smoking is responsible for about 2,3 million deaths a year, or almost one in four (24%) of all cancer deaths, according to the new global Atlas of Cancer.
Despite anti-smoking campaigns, an estimated 1,1 billion people continue to smoke worldwide. However, about 1,5 billion people in 55 countries are now protected by anti-smoking laws. The Atlas, produced by the American Cancer Society (ACS), the International Association for Cancer Control (UICC) and the International Agency for Research on Cancer (IARC), was presented at a global conference on cancer in Kazakhstan.
New data show that cancer is the No. 1 or No. 2 cause of premature death (before age 70) in 91 countries. The number of new cancers is expected to increase by 60% by 2040. Microorganism infections are responsible for about 15% of new cancers, but the rate varies dramatically, from only 4% in high-income countries to over 50% in several sub-Saharan African countries.
The four main carcinogens, which are responsible for over 90% of carcinogenic infections, are Helicobacter pylori, human papillomavirus (HPV), hepatitis B (HBV) and hepatitis C (HCV). Obesity increases the risk of 13 cancers and accounts for almost 4% of all new adult cancers worldwide.
About 40% of men and women over the age of 18 in the world, as well as 27% of boys and 24% of girls aged five to 18, are considered overweight and obese. Alcohol is responsible for 4,2% of all cancers, with large variations from country to country.
Atlas estimates that over the next 50 years there will be approximately 44 million new cases of cervical cancer worldwide. Breast cancer is the most common cancer in women in almost all countries of the world and is responsible for almost 25% of all new cancers in them. The risk of breast cancer in high-income countries is up to three times higher than in poor countries.
Each year, about 270.000 children are diagnosed with cancer. Life expectancy for at least five years after diagnosis varies considerably, with more than 80% of sick children in developed countries but only 20% in poor countries. Also, 3% to 6% of all cancers are estimated to be caused by people being exposed to carcinogens at work. Air pollution causes more than half a million deaths from lung cancer each year, especially in the fast-growing big cities of low- and middle-income countries.
Radiation therapy is indicated for about 60% of cancer patients to relieve their symptoms, shrink tumors before surgical removal, or destroy cancer cells to prevent metastases. However, the provision of radiotherapy is insufficient in several low- and middle-income countries. In Ethiopia, for example, a population of about 100 million is served by a single radiotherapy center.