CANCER RISK FACTORS

A risk factor is anything that increases a

person's chance of getting a disease.

Some risk factors can be changed, and others

cannot.

Different cancers have different risk factors

Risk Factor

RISK FACTOR

• Many factors contribute to the changes in cells that result in cancer.

• These risk factors may be intrinsic to an individual, such as sex, age, or genes.

• But most are external, in the individu’s general environment

• The interplay between the intrinsic and external factors is the major determinant of an individual cancer risk

Heredity? Behaviors? Other Factors?

100

50

50

Stomach Cancer(Number of new cases per 100,000 people)

U.S.Japan Japanese familiesin U.S.

100

70

7

0

Colon Cancer(Number of new cases per 100,000 people)

U.S.Japan Japanese familiesin U.S.

This suggests that the risk of developing the two kinds of cancer is not determined

primarily by heredity. The change in risk for cancer for Japanese families could

involve cultural, behavioral, or environmental factors predominant in one location and

not in the other.

What Causes Cancer?

Some viruses or bacteria

HeredityDiet

Hormones

RadiationSome chemicals

CANCER RISK FACTORS

MAJOR MODIFIABLE RISK FACTORS

OTHER MODIFIABLE RISK FACTORS

CANCER RISK FACTORS

NON - M0DIFIABLE RISK FACTORS

OTHER RISK FACTORS

MAJOR MODIFIABLE RISK FACTORS

• TOBACCO USE

• UNHEALTHY DIET

• INFECTIOUS AGENTS

• ULTRAVIOLET RADIATION

• PHYSICAL INACTIVITY

TOBACCO USE

• Tobacco use is the main cause of cancers of the lung,

larynx, oral cavity, and esophagus, and a major cause of

bladder and pancreas cancers.

UNHEALTHY DIET

• Up to 30% of cancers in developed countries may be

related to poor nutrition. Diets high in saturated fats and

low in fruits and vegetables increase the risk of cancers

of the breast, colon, prostate and esophagus

Tobacco

3000 chemicals are present in tobacco smoke, 60 of whichrecognize as carcinogen : nitrosamines and polycyclicaromatic hydrocarbons – either in initiation or promotion

Become carcinogen when activated by specific enzymesfound in many tissues in the body

The compounds can become part of DNA(deoxyribonucleic acid) molecules and possible interferewith the normal growth of cells

Diseases associated with cigarette smoking

Tobacco Use and Cancer

Some Cancer-Causing Chemicals in Tobacco Smoke

Lag Time

4000

3000

2000

1000

20-Year Lag Time Between Smoking and Lung Cancer

CigarettesSmoked

per Personper Year

Lung Cancer Deaths (per 100,000 people)

Year

Lung cancer (men)

Cigarette consumption (men)

1900 1920 1940 1960 1980

150

100

50

Tobacco

• Tobacco use is the environmental exposuremost widely known to be associated with anincrease risk of cancer as well as severalnonmalignant diseases.

• The associated cancer :Lung Pancreas

Larynx Kidney

Pharynx Cervix ( uterine )

Esophagus Breast

Bladder

Avoid Tobacco

15x

10x

5x

Non-smokerCigarettes Smoked per Day

Lung Cancer Risk Increases with Cigarette Consumption

Lung Cancer

Risk

0 15 30

Limit Alcohol and Tobacco

40x

30x

20x

10x

Alcoholic Drinks Consumed per Day

Packs of Cigarettes Consumed per Day

Combination of Alcohol and Cigarettes Increases Risk for Cancer of the Esophagus

Risk Increase

AND

CANCER AND TOBACCO

CANCER AND TOBACCO

Diet: Consume Fruits and Vegetables

Dicrease Cancer Risk

Diet: Limit Fats and Calories

0

Number of Cases (per 100,000

people)

Grams (per person per day)

Correlation Between Meat Consumption and Colon Cancer Rates in Different Countries

40

30

20

10

30020010080

INFECTIOUS AGENTS

• Infectious agents account for 18% of cancers worldwide.

Human papilloma virus, hepatitis B virus, and the Helicobacter

Pylori bacterium account for the largest number of cancers

due to infections.

ULTRAVIOLET RADIATION

• Sunlight is the major source of UV radiation, which causes

several types of skin cancers, the most common malignancy

in humans

PHYSICAL INACTIVITY

• A sedentary lifestyle increases the risk of colon cancers,

and may increase the risk for other types of cancer. Its

effects are closely related to an individual’s nutrition

Viruses

Virus inserts and changes genes forcell growth

Cancer-linked virus

Examples of Human Cancer Viruses

Some Viruses Associated with Human Cancers

AIDS and Kaposi’s Sarcoma

Kaposi’ssarcoma

Withoutdisease

Depressedimmunesystem

HIV infection

KSHV infection

Avoid Cancer Viruses

Noninfected women

HPV Infection Increases Risk for Cervical Cancer

Cervical Cancer

Risk

Low

High

Women infected with HPV

Bacteria and Stomach Cancer

H. pyloriPatient’s tissue sample

INFECTION AS A CAUSE OF CANCER

WORLD CANCER BURDEN CAUSED BY INFECTION

WORLD CANCER BURDEN CAUSED BY INFECTION

ULTRA VIOLET RADIATION

ULTRAVIOLET RADIATION

Protect Yourself From Excessive Sunlight

Physical Inactivity

STRENGTH OF EVIDENCE ON PHYSICAL ACTIVITY

AND DIETARY FACTORS

PROPORTION OF CANCERS

CAUSED BY MAJOR RISK FACTORS

OTHER MODIFIABLE RISK FACTORS

• ALCOHOL USE

• OCCUPATIONAL EXPOSURES

• SOCIOECONOMIC STATUS

• ENVIRONMENTAL POLLUTION

• OBESITY

• FOOD CONTAMINANTS

• IONIZING RADIATION

ALCOHOL USE

• Heavy alcohol use causes cancers of the oral cavity, esophagus, liver and upper respiratory tract. The cancer risk is greatly increased by concurrent smoking. Alcohol use also increases the risk of breast cancer.

OCCUPATIONAL EXPOSURES• Certain substances encountered of work are carcinogens,

including asbestos, arsenic, benzene, silica and second-hand tobacco smoke. Lung cancer is the most common occupational cancer.

SOCIOECONOMIC STATUS• Some cancers occur more often in people with a higher socio-

economic status ( SES ); others are more common in lower-SES populations. SES is most likely a marker for lifestyle and other risk factors described in this section.

Alcohol

Alcohol’s Link to Cancer

Epidemiologic research has shown a dose-respondentassociation between alcohol consumption and certain typesof cancer

Study on the mechanism by which alcohol contribute tocancer development

The strongest link between alcohol and cancer : cancer ofthe upper digestive tract (esophagus, mouth, pharynx,larynx )Less consistent with cancer of the liver, breast and colon

Upper digestive tract

cancer- alcohol

Chronic heavy drinkers have a higher incidence ofesophageal cancer, 75 % of esophageal cancersin US are attributable to chronic, excessive alcoholconsumption

Nearly 50 % of cancer of the mouth, pharynx, andlarynx are associated with heavy drinking

People who drink large quantities of alcoholovertime have increases risk of this cancersIf they drink and smoke the increase risk is evenmore dramatic

Liver cancer - alcohol

Prolonged, heavy drinking has been associatedin many cases with primary liver cancer

Liver cirrhosis, hepatitis B and C virus infections

often confound data

Studies of the interactions between alcohol,

hepatitis viruses, and cirrhosis essential toperform

Breast cancer - alcohol

Inconsistency and weakness of epidemiology findings

suggest that a third confounding factor, such as nutrition

and fat

Alcohol increases estrogen levels in premenopausal

women, which may promote breast cancer.

Other risk factor for breast cancer :

- age of menarche : < 10 years old

- age of menopause > 50 years old

- childless

- the first labour : > 35 years old age

- has operation for either benign or malignant tumours

- has family / relative suffered from breast cancer

Colon cancer – alcohol

Small and but consistent dose-dependent association

between alcohol consumption and colorectal

cancer,even controlling for fiber and other dietary factors.

Causality cannot be determined from the available data

with cancer of the stomach, pancreas, and lungs

The association is consistency weak and the majority of

studies have found no association

Mechanisms of

Alcohol-Related Cancers

Oncogenes

Preliminary studies show that alcohol may affect cancer

development at the genetic level by affecting oncogenes at

the initiation and promotion stages of cancer

Acetaldehyde, a product of alcohol metabolism, impairs a

cell’s natural ability to repair its DNA resulting in a greater

likelihood that mutations causing cancer initiation will occur

Avoid Carcinogens at Work

Some Carcinogens in the Workplace

carcinogen Occupation Type of cancer

Occupational Exposures

CULTURAL AND SOCIOECONOMIC FACTORS

AFFECTING CANCER SCREENING, EARLY DETECTION AND CARE

ENVIRONMENTAL POLLUTION

• Pollution of air, water and soil account for between 1% and

4% of all cancers in developed nations.

OBESITY

• Obesity is an important risk factor for endometrial, kidney,

gallbladder and breast cancers.

FOOD CONTAMINANTS

• Certain food contaminants are carcinogenic, including those

that occur naturally ( eg aflatoxins ) and those that are

manufactured ( eg pesticides )

IONIZING RADIATION

• For most, the greatest exposure to ionizing radiation comes

from medical X – rays. But we are all exposed to small

amounts of naturally occurring radiation.

Industrial Pollution

1930

Incidence of Most Cancers

Year

199019701950

obesity

BMI Category

Aflatoxins

Corn

Peanuts

Cottonseed

Nitrosamine

benzopyrine

FOOD

CONTAMINANT

cancer

IONIZING

RADIATION

NON – MODIFIABLE RISK FACTORS

• AGEING

• ETHNICITY OR RACE

• HEREDITY

• SEX

AGEING

• The risk of most types of cancer increases with age. The highest cancer rates occur among the elderly.

ETHNICITY OR RACE• The risk of many types of cancer varies between racial

and ethnic populations. Some of these differences are attributable to genetic differences, but most are due to differences in lifestyle and exposures to cancer – causing agents.

HEREDITY• Inherited “ cancer “ genes may cause 4% of all cancers.

Other genes affect our susceptibility to cancer risk factors.

SEX• Certain cancers occur in only one sex due to different

anatomy, eg prostate, uterus. Others occur in both sexes, but at markedly different rates, eg bladder, breast.

Cancer Risk and Aging

400

3000

2000

1000

Cancer Risk and Aging

Number of

Cancer Cases

(per 100,000

people))

Age of Person (in years)

Colon

Breast

0 20 40 60 80

Ethnicity

Heredity and Cancer

Inherited factor(s)

All Breast Cancer Patients

Other

factor(s)

5-10% Breast ca – are familial cancer

Heredity Can Affect Many Types of Cancer

Inherited Conditions That Increase Risk for Cancer

Name of condition Type of cancer

Genetic makeup

• Children with primary immunodeficiency disorders have an extremely high rate ofcancer lymphoid malignancies.

• The incidence of acute leukemia is

4 – 30 times higher in person with Down Syndrome> normal.

• Translocation of chromosomes 8 and 14 is associated with Burkitt’s lymphoma.

Genetic Testing

Sex

SEX DIFFERENCESNew cancers cases by sex

2002

REPRODUCTIVE AND HORMONAL FACTORS

Sexual activity

• Possible carcinogen or co-carcinogens

(e.g. certain viruses ) may be

venereal transmitted

• In the female reproductive tract, the uterine cervix has thehighest association with malignant diseases and itsprecursor.

– The cervix shows an increased vulnerability toneoplasia after exposure to infection, particularlyH(uman) P(apilloma) V(irus) infection

– Since squamous cervical neoplasia begins in thesquamocolumnar junction, hyperplasia in this areathat results from the irritation of infection may be onecause.

Risk factor for cervical uterine

cancer

• Inter sexual course beginning at the (too)

young age

• Changing sexual partners (quite often)

• Venereal infection disease (quite often)

• Multiparous

• Smoking habit

OTHER RISK FACTORS

• REPRODUCTIVE FACTORS

• IMMUNOSUPPRESSION

• MEDICINAL DRUGS

REPRODUCTIVE FACTORS

• Female hormones, menstrual history, and childbearing

affect the risks of breast, endometrial and ovarian cancers.

IMMUNOSUPPRESSION

• Certain viruses that suppress the immune system increase

the risk of lymphoma and kaposi sarcoma.

MEDICINAL DRUGS

• Some hormonal drugs can cause cancers, while others

reduce the risk. Rarely, anti – cancer drugs have caused

another cancer years later.

Reproductive system

REPRODUCTIVE AND HORMONAL FACTORS

Immunosuppresion

AIDS and Kaposi’s Sarcoma

Kaposi’ssarcoma

Withoutdisease

Depressedimmunesystem

HIV infection

KSHV infection

IMMUNOSUPRESSION

??? Medicinal drugs

Risk Factors of Cancer

Cancer Type Risk Factor

Lung Cancer Tobacco smoke

Radon

Asbestos and other substances

Air pollution

Breast Radiation

Genetic changes (Inherited mutation)

Colorectal Cancer polyp

Genetic alteration

Diet

Cigarette smoking

Ulcerative colitis or chon's disease

Prostate Diet

Certain prostate changes

Race Africans Americans

Risk Factor/ Cancer Type

Cancer Type Risk Factor

Liver Hepatitis viruses (HCV.HBV)

Pancreas Smoking

Diabetes

Being male

Chronic pancreatitis

Kidney Tobacco smoking

High blood pressure

Von-Hippel-Lindau syndrome (VHL)

Leukemia Radiation

Chemotherapy

Certain disease (Down syndrome)

Human T cell leukemia virus

Myelodysplatic syndrome

Risk Factor/ Cancer Type

Cancer Type Risk Factor

Bladder Occupation

Certain infection

Tobacco smoking

Race Twice as often as Africans Americans

Treatment with cyclophosphamide or arsenic

Uterine Endometrial hyperplasia

Race Africans Americans

Hormonal replacement therapy

Obesity

Melanoma Dysplastic nevi

Fai skin

Weakened immune system

Sever blistering/Sunburn

UV irradiation

Source:http://ishwaryatechnosolutions.com/cancer.aspx

Risk Factor/ Cancer Type

Microorganism Cancer

Human papilloma virus Cervical cancer

Helicobacter pylori Stomach cancer

Hepatitis B and hepatitis C viruses Liver cancer

Human T-cell leukemia/lymphoma

virus

Lymphoma and leukemia

Human immunodeficiency virus Lymphoma and a rare cancer called

Kaposi's sarcoma

Epstein-Barr virus Lymphoma

Human herpes virus 8 Kaposi's sarcoma

Certain viruses or bacteria may increase the risk of developing cancer

Risk Factors for Breast Cancer

Risk Factors for Prostate Cancer

THANK YOU