CANCER PREVENTION

Dr. Gily Ionescu2004

INTRODUCTION• Cancer is the second cause of death in the

US. – 1.4 million new cases, >560,000 deaths/year

(>1/minute)– >$110 billions total costs – 1 in every 2 men and 1 in every 3 women will develop

some form of cancer during their lifetime– 10 million cases of cancer worldwide in 1999 (WHO)

• Cancer – name for a group of > 100 diseases– Abnormal cell multiplication

CAN CANCER BE CAN CANCER BE PREVENTEDPREVENTED??

30%

30%

5%

5%

5%

5%

5%

3%

3%

3%2% 2% 1%1%

Radiation & env. pollution Radiation & food contaminantsSmoking & env. pollutionSmoking & diet?

CAUSES OF CANCER - TEST

30%

30%

5%

5%

5%

5%

5%

3%

3%

3%2% 2% 1%1%

Tobacco

Diet/Obesity

Sedentary lifestyle

Occupational factors

Family history of cancer

Viruses

Perinatal factors

Reproductive factors

Alcohol

Social status

Environmental pollution

Ionizing/ultraviolet radiation

Prescription drugs/medical procedures

Salt/other food additives/contaminants

CAUSES OF CANCER

Source: Harvard University, 1999

Tobacco – 30%

• An estimated 30 percent of all US cancer deaths can be attributed to tobacco use

• In 1993, EPA designated tobacco smoke as a Group A carcinogen, for which there is no known safe level of exposure

• Passive smoking can cause cancer

Sedentary lifestyle - 5%• Higher levels of physical activity

– can reduce the incidence of colorectal cancer– may help reduce cancers of the breast and

prostate.

• Regular physical activity during childhood and adolescence may prevent excessive weight gain and delay onset of menstruation – early age at menarche is a major risk factor

for breast cancer.

Occupational factors – 5%• Examples:

– 4-Aminobiphenyl, Arsenic, Asbestos, Benzene, Benzidine, Benzotrichloride, Bis (chloromethyl) ehter, Cadmium and compounds, Chromium (VI) compounds, Coal-tars, Erionite, Ethylene oxide, Mineral oils (untreated and mildly treated), 2-Naphthylamine, Nickel compounds (expect Ni metal), Soots, Sulphur dichlordiethyl, Talc containing asbestiform fibers, Dioxin, Vinyl chloride, Wood dust

• Are known to cause cancer in lung, bladder, and bone marrow

Family history of cancer - 5%• Increased susceptibility to cancer due to

– genetic mutations running in families– genetic polymorphisms that affect the

absorption, transport, metabolic activation, or detoxification of environmental carcinogens

• These processes could play an interactive role in the majority of cases of cancer

• Preventive measures – genetic counseling, through which couples may

decide not to have children– more frequent screening among those at high

risk

Viruses & biologic agents - 5%• Human papilloma viruses (HPV) types 16 &

18– cancer of the uterine cervix

• Hepatitis B virus (HBV) – liver carcinoma

• Preventive measures– Pap screening programs– anti-HBV vaccine– improved screening of blood and blood products– use of disposable syringes and needles

Perinatal growth factors - 5%

• Excess energy intake early in life – probably responsible for the positive

association between height and the risk of breast cancer and possibly other cancers.

• Larger birth weight – associated positively with breast and

prostate cancer.

Reproductive factors - 3%

• Early age at menarche• Late age at first birth• Late age at menopause

– Increased risk of breast cancer

• Parity– Decreased risk of endometrial and ovarian

cancer

• Multiple sexual partners– Increased risk of cervical cancer

Alcohol - 3%

• Alcohol interacts with tobacco smoking in the causation of cancers of the upper respiratory and gastrointestinal tracts.

• Alcohol is implicated in – cirrhosis-mediated liver cancer – may cause a proportion of cancer of the

breast and the large bowel

• Safest route = zero intake

Socioeconomic status - 3%

• Poverty is associated with a higher incidence of of some types of cancer:– Lung– Stomach– uterine cervix

• Poverty is associated with increased exposure to tobacco smoke, alcoholism, poor nutrition, and certain infectious agents.

Environmental pollution - 2%• Investigations have

focused on – air pollution– water fluoridation – chlorinated water

byproducts– metabolites of

organochlorine pesticides (e.g., DDT)

– residential proximity to hazardous waste sites or contaminated wells

• Few causal links are firmly established.

                                                                                        

                                                    

Ionizing and UV radiation - 2%• UV is responsible for over

90% of skin cancers– prolonged sun exposure – hx of severe sunburns

• Ionizing radiation – unquestionably

carcinogenic, but risk is generally overestimated.

• only 1% of Japanese atomic bomb survivors died from radiation-related cancers.

• Other types of radiation– risk is small for usual

exposure

Prescription drugs & medical procedures - 1%• Radiotherapy • Cancer chemotherapeutic

and immunosuppressive drugs – Cancer of bone marrow

• Menopausal estrogens – Cancer of the

endometrium, possibly breast

• Anabolic steroids – Liver cancer

• Phenacetin analgesics – Kidney & pelvis cancers

Salt & other food additives and contaminants - 1%

• Reduction of salt intake could reduce stomach cancer risk.

DIET & CANCER

                                                         

DIET & CANCER

                                                         

DIET & CANCER

                                                         

DIET & CANCER

                                                         

DIET – 30%

• The link between diet and cancer has been investigated for many years. – Hundreds of studies published to date

• In 1997, the American Institute for Cancer Research (AICR) has published the results of its meta-analysis “Food, Nutrition and the Prevention of Cancer: A Global Perspective”

DIET & CANCER - AICR• AICR’s expert panel

reviewed the literature on diet and cancer – Over 4.500 studies– Published 14 dietary

recommendations designed to reduce the risk of cancer

                  

Eat a plant-based diet

1. Choose predominantly plant-based diets rich in a variety of vegetables and fruits, pulses (legumes) and minimally processed starchy staple foods.

Maintain a healthy weight

2. Avoid being underweight or overweight and limit weight gain during adulthood to less than 5 kg (11 pounds).

Exercise

3. If occupational activity is low or moderate, take an hour's brisk walk or similar exercise daily, and also exercise vigorously for a total of at least one hour in a week.

Vegetables and fruits

4. Eat 400 - 800 grams (15 - 30 ounces) or five or more portions (servings) a day of a variety of vegetables and fruits, all year round.

Other plant foods

5. Eat 600 - 800 grams (20 - 30 ounces) or more than seven portions (servings) a day of a variety of cereals (grains), pulses (legumes), roots, tubers and plantains. Prefer minimally processed foods. Limit consumption of refined sugar.

Alcohol

6. Alcohol consumption is not recommended.

Meat

7. If eaten at all, limit intake of red meat to less than 80 grams (3 ounces) daily. It is preferable to choose fish, poultry or meat from non-domesticated animals in place of red meat.

Total fats and oils

8. Limit consumption of fatty foods, particularly those of animal origin. Choose modest amounts of appropriate vegetable oils.

Salt and salting

9. Limit consumption of salted foods and use of cooking and table salt. Use herbs and spices to season foods.

Food Storage

10. Do not eat food which, as a result of prolonged storage at ambient temperatures, is liable to contamination with mycotoxins.

Preservation

11. Use refrigeration and other appropriate methods to preserve perishable food as purchased and at home.

Additives and residues

12. When levels of additives, contaminants and other residues are properly regulated, their presence in food and drink is not known to be harmful. However, unregulated or improper use can be a health hazard, and this applies particularly in economically developing countries.

Preparation 13. Do not eat charred

food. For meat and fish eaters, avoid burning of meat juices. Consume the following only occasionally: meat and fish grilled (broiled) in direct flame; cured and smoked meats.

Dietary supplements

14. For those who follow the recommendations presented here, dietary supplements are probably unnecessary, and possibly unhelpful, for reducing cancer risk.

Good News!• Healthy diet + physical activity + weight

control = risk of cancer lowered by 30% - 40%.

• Healthy diet + smoking cessation = risk of cancer lowered by 60% - 70%.

• 375.000 cancer cases could be prevented each year in the US by diet alone!

• One study showed a 15% decrease in overall cancer risk with each additional serving of fruits and vegetables.

Cancer – a preventable disease!

• 60% - 70% of cancers are related to lifestyle factors:

• smoking, diet, lack of exercise, overweight, alcohol, etc.