Debunk the myth of cancer and start everyday life’s cancer prevention

Written for “the World Cancer Day 2014”

In the past 30 years, the incidence of cancer in China has been gradually increasing, and cancer becomes closer to everyone. In average, 1 out of 5 or 6 people dies because of cancer. As the cancer pathogenesis mechanism is still not clear for most of the cancer types, the goal to eliminate cancer is still far from being achieved. Therefore, cancer stays in everyone’s mind as a huge mystery which is always mentioned with tremendous fear, and followed by numerous misunderstandings and bias: some believe that cancer is “the will of God”, that it cannot be prevented or treated and equals death penalty. This phenomenon is also popular in other countries.

Therefore, the Union for International Cancer Control decided that the theme for “the World Cancer Day” (February 4th) this year will be “Debunk the Myth”, calling for the health organizations and institutions all over the world to collaborate in spreading the scientific knowledge on cancer. The goal is to provide the public with a proper understanding about cancer, its prevention and treatment, and have effective rehabilitation to improve cancer patients’ quality of life.

It is well known that most types of cancer can be induced under the long term effect of multiple carcinogens. The percentage of cancer caused purely by genetic factors is under 5%, and 80% of the carcinogens appear in the environment of peoples’ everyday life and living habits. The World Health Organization (WHO) believes that healthy living habits can result in successful prevention of 30% of cancers. A “Balanced diet”, “Proper physical activities”, “No smoking and limited drinking” and “Mental health” are the four basics for a healthy lifestyle, therefore effective ways for cancer prevention.

A) No Smoking and Limited Drinking

Smoking is a highly risk factor responsible for more than 20% of the malignant tumors such as lung, esophageal, larynx, oral, bladder, kidney, pancreatic, stomach and cervical cancers. It is estimated that 70% of lung cancers are caused by smoking. The smoke contains dozens of carcinogens, such as polycyclic aromatic hydrocarbons, nitrosamines, heterocyclic aromatic amines, and inorganic compounds such as aldehydes. Non-smokers can suffer from long-term “passive smoking” while staying with regular smokers, thereby increasing cancer risk. The most effective cancer prevention would be a change of lifestyle by the complete cessation of smoking.

If we look around the world, there are already some good news. Since the 1970’s, in the United States and other developed countries, a movement to reduce tobacco consumption has appeared. Since the 1990’s, mortality and incidence of a variety of common tumors including lung cancer, has declined or become stable. Therefore, for yourself and your environment, do not smoke or quit smoking.

Concerning the alcohol, once it enters the body, the main carcinogen released in vivo is metabolite acetaldehyde. Epidemiological studies have shown that alcohol can induce the cancers of pharynx, mouth, and esophagus, as well as other malignant tumors. As regular smokers may also have drinking habits, the combination of alcohol and cigarette creates a fatal synergy, thereby increasing the risk of cancer.

B) Balanced Diet

A balanced diet is also an important measure for cancer prevention by developing healthy eating habits and controlling the quantity of food ingested. Medical studies show that overweight or obese people tend to develop esophageal, colon, breast, endometrial and kidney cancers. Eating more fruits and vegetables is good for cancer prevention, especially food rich in cellulose. On the contrary, over-consumption of high-fat category food, especially red meat, increases the risk of a variety of tumors.

In the American Cancer Society Guidelines on Nutrition and Physical Activities, it is recommended to eat: at least 5 different types of fruit and vegetable per day, more whole grain food, less processed refined grains and sugars, and less red meat, especially those being processed or rich in fat.

Meanwhile, alternation of traditional food processing is also a good way to prevent numerous cancers. For example, minimize fried, smoked, grilled or marinated food, as well as sodas. Those processes produce different levels of polycyclic aromatic hydrocarbons and nitrosamines carcinogens. In addition, it is recommended to also avoid food that is too hot, too spicy, too hard, or too sour, as these eating habits tend to cause mechanical irritation of the esophagus. In the long term those repeated abrasions could easily provoke chronic inflammations, leading to esophageal cancer.

(C) Proper Physical Activities

Vocational laboring or recreational sport activities can both decrease the risk of common cancers such as breast, colon, pancreatic, duct bile, endometrial and lung cancer. The greater the physical efforts are, the smaller the risk of cancer is.

In China, with the development of the society and progress of technologies, people are less and less engaged in heavy physical labor, while more and more sitting for professional purposes. Therefore, doctors advise to keep a physically active lifestyle through exercise to balance the body’s intake of calories and maintain a healthy weight. Adults should practice moderate exercise at least 30 minutes a day, 5 days a week. Children and young adults should practice moderate to intense exercises at least 60 minutes a day, 5 days a week.

(D) Mental Health

Modern cancer medicine recognizes cancer as both a mental and physical malignant disease influenced by the “four human quadrants”: physical, mental, emotional, and spiritual. The role of psychosomatic factors such as stress, emotional states, life events, personality traits and psychosocial factors in the pathogenesis of tumor diseases can not be ignored.

Long-term stress or persistent mood disorders affect endocrine function and brain neurotransmitters, reducing the body's immune function and thereby increasing the likelihood of cancer resistance.

Therefore, reduce stress, do the necessary psychological adjustments, express the negative emotions, and actively seek psychological treatment for sleep disorders and other problems, help maintain mental health, increase the body's immune system, and prevent cancer on the basis of physical and mental balance.

Investigations on the causes of cancer show that carcinogenic factor depends on everyday habits, such as breathing, diet, sports, hobbies and other daily activities.

Therefore, prevention of cancer starts little by little in the daily routine; let’s get rid of our bad habits and have a healthy lifestyle in order to achieve our purpose of putting cancer away.

Sun Yat-sen University Cancer Center  

Cao Su-Mei, Huang Wei