At least one-third of all cancer cases are preventable.
Prevention offers the most cost-effective long-term strategy for the control of cancer.
(Adapted from WHO cancer control programme)

What are the major causes of cancer?

• Tobacco.
• Inadequate intake of fruit and vegetables.
• Excess alcohol intake.
• Obesity.
• Too much sun.

Cancer risk can be reduced 60-70% by:-

• Sensible food choices.
• A healthy weight.
• Physical activity.
• Not smoking.

Less Common Causes of Cancer:-

• Genetics.
• Pollution.
• Radiation.
• Occupational hazards.
• Tobacco: Tobacco is the single largest preventable cause of cancer in the world today. It causes 80-90% of all lung cancer deaths, and about 30% of all cancer deaths in developing countries, including deaths from cancer of the oral cavity, larynx, oesophagus and stomach.
• Diet, physical activity and health: Dietary modification is another important approach to cancer control. There is a link between overweight and obesity to many types of cancer such as oesophagus, colorectum, breast, endometrium and kidney. Diets high in fruits and vegetables may have a protective effect against many cancers. Conversely, excess consumption of red and preserved meat may be associated with an increased risk of colorectal cancer. In addition, healthy eating habits that prevent the development of diet-associated cancers will also lower the risk of cardiovascular disease. Regular physical activity and the maintenance of a healthy body weight, along with a healthy diet, will considerably reduce cancer risk.
• Infectious diseases: Infectious agents are responsible for almost 22% of cancer deaths in the developing world and 6% in industrialized countries. Viral hepatitis B and C cause cancer of the liver; human papilloma virus infection causes cervical cancer; the bacterium Helicobacter pylori increases the risk of stomach cancer. Preventive measures include vaccination and prevention of infection and infestation.
• Ionizing radiation: Exposure to ionizing radiation is also known to cause to certain cancers. Excessive solar ultraviolet radiation increases the risk of all types of cancer of the skin. Avoiding excessive exposure, use of sunscreen and protective clothing are effective preventive measures.
• Occupational hazards: Asbestos can cause lung cancer; aniline dyes have been linked to bladder cancer; and benzene can lead to leukaemia. The prevention of certain occupational and environmental exposure to these and other chemicals is another important element in preventing cancer.

Specific Cancer Prevention Methods

Cancer Risk	Recommended Screening	Preventive Recommendations
Breast cancer	Mammography annually or biennially	1.Breast self-examination monthly 2.Clinical breast examination annually
Cervical cancer	1.Annual Pap smear 2.HPV test	HPV Vaccination
Colorectal cancer	1.Carcinoembryonic Antigen (CEA) annually 2.Colonoscopy every 3-5 years	High-fiber diet
Gastric cancer	Endoscopy annually	Eradication of Helicobacter pylori
Leukaemia cancer	Peripheral blood smear
Liver cancer	1.Hepatitis screening 2.Alpha-fetoprotein (AFP) 3.USG abdomen	1.Hepatitis B vaccination 2.Clear fatty liver
Lung cancer	1.Chest X-ray 2. CT lung every 3 years	Smoking cessation programme
Nasopharyngeal cancer	1.Nasopharyngoscopy 2.ELISA against EBV specific IgA
Oral cancer	Laryngoscopy
Ovarian cancer	1.CA 125 annually 2.Ultrasound Pelvis annually
Prostate cancer	1.Ultrasound Pelvis annually 2.Prostate Specific Antigen (PSA) annually
Thyroid cancer	1.Ultrasound of thyroid 2.Thyroid scan

Preventive recommendations for all cancer types:

• Dietician referral (BMI> 25 kg/m2 or dietary habits risk factor for cancer)
• Smoking cessation programme

References:

• American Cancer Society: Cancer Facts and Figures 2010. Atlanta, Ga: American Cancer Society, 2010.
• Management of Breast Cancer 2010. Malaysian Clinical practice Guidelines.
• Management of Cervical Cancer. 2003. Malaysian Clinical Practice Guidelines.
• National Cancer Institute (U.S. National Institute of Health). Retrieved from World Wide Web 26 May 2011: http://www.cancer.org