Intrinsic vs. extrinsic factors Cancer caused by intrinsic factors, i.e. inherited mutations, can only be prevented by screening and appropriate early intervention Cancer Prevention 1.National Cancer Institute, Understanding Cancer, Cancer caused by extrinsic factors can be prevented by reducing or eliminating exposure to these factors (e.g. chemicals, tobacco, radiation, viruses) Radiation Viruses or bacteria Carcinogenic chemicals

Tobacco products 1.National Cancer Institute, Understanding Cancer, WHO Fact Sheet 339, Artwork originally created for the National Cancer Institute. Reprinted with permission of the artist, Jeanne Kelly. Copyright The use of tobacco products is implicated in ~33% of all cancer deaths 1 ~1 person dies every 6 seconds due to tobacco 2 The combination of tobacco and alcohol products appears to be particularly dangerous 1 As well as lung cancer, tobacco products have also been implicated in cancer of the mouth, larynx, oesophagus, stomach, pancreas, kidney, and bladder 1 Avoiding tobacco is the single most important factor in reducing cancer risk Lung Cancer Risk Increases with Cigarette Consumption 1 15x 10x 5x Lung Cancer Risk Cigarettes Smoked per Day Non-smoker

Excessive exposure to UV radiation 1.WHO Fact Sheet 305, Excessive UV exposure, particularly in fair- skinned individuals can cause: 1 cutaneous malignant melanoma squamous cell carcinoma basal cell carcinoma In 2000, >200,000 cases of melanoma were diagnosed worldwide 1 Stratosphere Sun exposure Ozone Epidermis Dermis Hypodermis UV-A UV-B UV-C

Diet National Cancer Institute, Understanding Cancer, Artwork originally created for the National Cancer Institute. Reprinted with permission of the artist, Jeanne Kelly. Copyright Unlike tobacco products, UV radiation and alcohol, dietary components that influence cancer risk have been difficult to determine 1 Limiting fat and calorie intake appears to reduce cancer risk 1 A diet rich in meat increases cancer risk, especially colon cancer 1 Number of Cases (per 100,00 People) Correlation Between Meat Consumption and Colon Cancer Rates in Different Countries Grams (per person per day) N.Z U.S.A. DEN. CAN G.B. SWE NOR NETH GERMANY ICE ISR JAM FIN P.R. HUNG ROM COL NIG JAPAN YUG POL CHILE

HPV Infection Increases Risk for Cervical Cancer 2 Viruses 1.Liao JB. Viruses and Human Cancer. YJBM 2006 (79); National Cancer Institute, Understanding Cancer, Artwork originally created for the National Cancer Institute. Reprinted with permission of the artist, Jeanne Kelly. Copyright Worldwide, 15% of all cancers may be caused by viruses, including: 1 Epstein-Barr virus Human papilloma virus (HPV) Hepatitis B virus Human herpes virus-8 Human T lymphotrophic virus type 1 Hepatitis C virus Reducing exposure to these viruses reduces cancer risk In the case of HPV, avoiding unprotected sex with many partners reduces the risk of contracting this virus 2 High Low Non-infected women Cervical Cancer Risk Women infected with HPV

Strategies for prevention about cancer and risk factors (warnings on cigarette packets, campaigns about sun and exposure to UV radiation) pink ribbons for breast cancer, world cancer day dont smoke, stay out of the sun, avoid toxic chemicals and polluted areas cervical smear, mammography, colonoscopy HPV vaccine to reduce risk of cervical cancer; Hep B vaccine to reduce risk of liver cancer normal weight, healthy diet, exercise regular check-ups, seek medical attention early Education Awareness campaigns Risk avoidance Screening Vaccines Lifestyle Healthcare