Understanding Cancer Prevention

文:张元吉教授

Can Cancer be prevented?  What can I do to prevent cancer?  These are the most common questions in everyone’s mind and the most frequently asked topics. When we contact cancer patients either friends or relatives, these questions come up automatically and the answer to both questions is yes and yes. However, the issues on cancer prevention are complex and intricated.  The purpose of this article is to convey few fundamental concepts to add your understanding. 

First of all, we need to identify the cancer causing agents (carcinogen) and cancer formation process (carcinogenesis) in order to know how to prevent cancer.  If we know carcinogen and carcinogenesis of every cancer, i.e the etiology of cancer, then it would have been very easy not to get cancer, simply by avoiding the carcinogens.  Unfortunately, it is not so simple because etiology of many cancers is unknown and carcinogenesis is a complicated, chronic, multi-step process without our full understandings.  Exposure to certain carcinogens increase the risk of developing certain cancer but not in 100% of people who have been contaminated due to different genetic constitutions and other risk factors.  So some people are more susciptable to develop lung cancer from smoking cigarettes and some do not develop.  Many carcinogens and risk factors have been identified, some are listed in Table 1, and these include physical, chemical, environmental, life-style chronic infections, long term immune-suppression and so forth.  If we can reduce or eliminate smoking cigarettes, we shall see the reduction of lung cancer in a few years to decades but we would not see the complete elimination of lung cancer, as lung cancer may take decades to form and may have different etiologies than just cigarette smoking.

Secondly there are ways to reduce our risk of getting cancer in addition to avoid exposure to carcinogen.  For example certain type of, human papilloma virus (HPV) causing cervical cancer and some head/neck cancer.  Vaccination against causative HPV some can effectively reduce the incidence of cervical cancer close to zero.  Similar

Thirdly, early diagnosis and treatment are effective in curing cancer.  Cancer screening has been shown to make early diagnosis and improve survival rate ; this include, mammogram for screening breast cancer, pap smear and pelvic examination for cervical cancer, Colonoscopy for colorectal cancer, low dose CT scan of the chest for lung cancer.  General health check-up should be done once a year after age 40.  You should consult your physician regarding more specific cancer screening as every one may have different risk. scenario also apply in the case of hepatocellular (liver) cancer caused by chronic hepatitis B virus.  Hep B vaccine has been shown to decrease the incidence in liver cancer.

Lastly, what we can do every day to prevent cancer is to lead a healthy lifestyle including healthy diet and exercise regularly.  I like to emphasize the importance of regular exercising including practice of Infinite Youth Qi Gong.

Physiologically, exercise has many benefits such as

  1. Improve circulation and cardiac functions
  2. Increase oxygenation in the blood
  3. Maintain homeostasis, reducing fatty tissue
  4. Enhance immunity
  5. Preventing aging of the brain
  6. Reduce risk of cancer occurrence and reccurrence

The benefit of exercise is related to the amount and intensity of exercise, i.e. more exercise, more benefit.  It is worth noting that even milder exercise can benefit our health with increased healthy life.  Regular exercise (30minutes non-stop exercise 5 times a week) compared to no or less exercise has been shown to prolong survival in general healthy population, and also decrease the risk of developing cancers and lower the incidence of recurrence rate of breast cancer patients after initial diagnosis and treatment.  This means that even one has the diagnosis of breast cancer, exercise regularly is still beneficial by decreasing the risk of recurrence.

In conclusion, some cancers can be prevented and diagnosed early with high possibility of cure.  There are ways to reduce cancer risk including exercise regularly.

Table 1