GENEVA, Switzerland, April 3 (UPI) -- Global cancer rates could increase by 50 percent to 15 million new cases a year by the year 2020, a World Health Organization report published Thursday projects.
However, effective public health action by governments and medical practitioners coupled with adoption of healthy lifestyles could stem this trend, and prevent as many as trend up to one-third of new cancers worldwide, the report said.
In 2000, 5.3 million men and 4.7 million women developed a malignant tumor and 6.2 million died from cancer, according to WHO's first "World Cancer Report." The report was compiled by the International Agency for Research on Cancer.
"A wide variety of cancers are caused by tobacco of which lung cancer, which causes about 1.2 million deaths a year, is perhaps the most important," said Derek Yack, WHO executive director for non-communicable diseases, at a news conference.
Major drivers behind the current and future increases in cancer include risk factors such as increased aging, tobacco, diet, and physical inactivity and infections, Yack said. In poor countries, up to 23 percent of malignancies are caused by infectious agents, including Hepatitis B and C viruses, which can lead to liver cancer, and human papillomavirus, the cause of most cervical and ano-genital cancers, the report said.
After lung cancer, the second most common new cases annually are cancers of the breast with just over 1 million, followed by colorectal cancer with 940,000 cases, and stomach, liver and cervical cancer with 870,000, 560,000 and 470,000 cases, respectively.
The report also said the three leading cancer killers are different from the three most common forms, with lung cancer responsible for 17.8 percent of all cancer deaths, stomach cancer 10.4 percent and liver cancer 8.8 percent.
Dr. Paul Kleihues, IARC director, and co-author of the 350-page study, said the world has an opportunity to stem the increase in cancer.
"Action now can prevent one-third of cancers, cure another third, and provide palliative care to the remaining third who need it," he said.
Central to palliative care, according to the report, are symptom relief and support for the patients and their families.
"Adequate pain control is an essential component of cancer care," it states.
In affluent societies, which are marked by high-caloric diets that are rich in fat, combined with low physical activity, the typical malignancies include cancers of the breast, colon/rectum, uterus, gall bladder, kidney and the esophagus, according to the report.
Yack said consumption of fruits and vegetables has very beneficial effects in reducing certain kinds of cancers, in particular of the colon, and perhaps it also is responsible for the decline in stomach cancers seen worldwide.
Epidemiological studies indicate frequent consumption of fruits and vegetables also can reduce the chance of developing cancers of the pharynx, lung, stomach, colon and cervix.
There also is increasing evidence, Yack said, of the beneficial effects of physical activity on cancer, such as cancer of the breast.
Certain screening tests such as mammography and Pap smear tests are also helping in the fight to combat cancer.
For example, the report states, recent analyses by an IARC working group concluded under trial conditions, "mammography screening may reduce cancer mortality by 25-30 percent."
There also is emerging evidence prostate cancer screening, which assesses blood levels of prostate-specific antigen, or PSA, could result in lower mortality rates.
"About a third of cancers we believe are treatable and preventable," he said.
The report concludes the best possible primary prevention against cancer remains avoidance of exposure to cancer-causing agents, such as tobacco and industrial carcinogens.