China is waking up to the presence of a silent killer that claims 160,000 lives across the country each year, particularly in the country's northwestern regions, following the release of a report on stomach cancer.

Both the number of incidents and the mortality rate of stomach cancer in China are more than twice the world average, according to Professor Jin Maolin of the School of Oncology in Peking University, with the disease claiming nearly one fourth of all cancer deaths in China.

According to the statistics, incidents and mortality rates of stomach cancer are at their peak in western provinces such as Gansu and Qinghai and the lowest in southern provinces such as Guangdong. The survey conducted in Qinghai revealed that 80 percent of local residents were smokers and drinkers, and 97 percent liked spicy food and pickles-all potential factors in causing stomach cancer.

Stomach cancer is the second most deadly cancer worldwide, while cancer is the leading cause of death globally and in China. In 2005, almost 1 million people around the world died from stomach cancer, accounting for 1.72 percent of total deaths. In 2007, cancer contributed to 28.5 percent of total deaths in urban areas, and 24.8 percent of total deaths in rural areas across China, according to data released by the Ministry of Health.

The dangerous part of stomach cancer is that it is a silent killer. In the early stages, stomach cancer is asymptomatic, or causes only nonspecific symptoms. By the time symptoms occur, the cancer has advanced into its late stages and may have spread to other parts of the body.

If stomach cancer is treated shortly after it grows in the mucous membrane, 95 percent of patients survive at least five years after the disease is diagnosed. For patients in advanced stages of the disease, the five-year survival rate is only about 20 percent.

Although a cancer diagnosis is often seen as a death sentence, there is hope. According to the World Health Organization (WHO) over 40 percent of all cancers can be prevented and others can be detected early, treated and cured.

Researchers have found a number of stomach cancer risk factors, including consumption of salted, smoked or poorly preserved foods, cigarette smoking, low consumption of fruits and vegetables, infection of Helicobacter pylori, previous stomach surgery, family history of gastric cancer, pernicious anemia, some types of stomach polyps and chronic gastritisa.

Approximately 35 to 50 percent of cancer incidents in China are caused by unhealthy diet, poor sanitation and improper cooking methods, according to information from Cancer Institute and Hospital, Peking Union Medical College. Chemicals such as nitrite and nitrate are often found in preserved foods and can turn into a carcinogen in the stomach. Carcinogens can also be produced when foods are deep fried or barbecued. Fresh vegetables such as tomatoes, sweet potatoes and carrots can reduce the risk of cancer, Jin explained.

The incidence and mortality rate of stomach cancer differ significantly across regions due to differences in lifestyle and sanitation conditions. According to the World Cancer Report published by the WHO, about 60 percent of cases occurred in developing countries, with the highest incidence rates in eastern Asia, the Andean regions of South America and eastern Europe.

A key to treatment

Early detection and treatment is key to cutting stomach cancer mortality rates, noted Yu Zhonglin, a digestion expert in Beijing Friendship Hospital Affiliated to Capital University of Medicine. At his initiation, a free mass screening of stomach cancer in high-risk areas such as Gansu, Qinghai and Jilin provinces was conducted from May to September last year.

The medical team, consisting of more than 10 experts from several hospitals, examined nearly 5,000 people, using such techniques as serum pepsinogen screening, gastroscope examination, and pathologic investigation. In Qinghai, 25.2 percent of people tested positive during the serum pepsinogen screening, of whom 25.2 percent were diagnosed with stomach cancer. Among the 1,348 people screened in Gansu Province, 10 cases of stomach cancer were diagnosed. In addition, 70 percent of the people examined were infected with Helicobacter pylori.

To promote public awareness of cancer prevention and treatment, the Chinese Anti-Cancer Association initiated the Cancer Prevention and Detection Week. During the 14th anti-cancer week this year, doctors offered free consultations on smoking and cancer to the public.