Wirsma Arif HarahapSurgical Oncologist

Surgery Department - Andalas University

According to GLOBOCAN, an estimated 12.7 million new cancer cases and 7.6 million cancer deaths occurred in 2008.

56% of new cancer cases in 2008 occur within developing regions) and cancer mortality (63% of cancer deaths).

Cancer is neither rare anywhere in the world, nor confined to high-resource countries. "Striking differences in the patterns of cancer from region to region are observed,"

Cervix and liver cancers are much more common in developing regions of the world, whereas prostate and colorectal cancers are more common in developed regions.

The most commonly diagnosed cancers worldwide are : lung (1.61 million, 12.7% of the total), breast (1.38 million, 10.9%) colorectal cancers (1.23 million, 9.7%).

The most common causes of cancer death are lung (1.38 million, 18.2% of the total), stomach (0.74 million, 9.7%) and liver cancers (0.69 million, 9.2%).

Cancer prevalence : 4.3 / 1000 people

SIRS 2007 : Breast cancer 8.227 cases (16.85%). Breast cancer incidence : 26 per 100.000 women.

Cervical cancer : 16 per 100.000 women

“Distribution and determinants of disease

frequency in human populations”

1775British surgeon,

Percival Pott reported probably

the first description of occupational

carcinogenesis in the form of scrotum

cancer among chimney sweeps.

Tight corsets and cancer

1842 Rigoni-Stern, Italian physician, observed that

married women in the city were getting

cervical cancer, but nuns in nearby convents

weren’t. He also observed that nuns had

higher rates of breast cancer, and suggested

that the nuns’ corsets were too tight.

Criteria Risk Factor for Disease

1) Timing Exposure occurs before development

of disease or during its progression

2) Strength Is dose-dependent Cessation of exposure can modify disease

3) Prevalence Occurs in multiple populations

4) Relationship to

other risk factors

Is independent Can also act synergistically

5) Plausibility Produces structural‡ or functional changes

which are events in mechanism of disease

‡ anatomic or molecular

1700s: tobacco and cancer

Reports of cancer risks associated with

tobacco in the 18th century included

snuff taking and nasal cancer, reported

by Hill in 1761, and pipe smoking and

lip cancer by von Soemmering in 1795.

Tobacco and Lung Cancer Asbestos and Lung Cancer Leather Industry and Nasal Cancer Dyes and Bladder Cancer Ionizing Radiation and Many Cancers DES and Vaginal Adenocarcinoma EBV and Burkitt’s Lymphoma HPV and Cervical Cancer

Uncover new etiologic leads

◦ study of the distribution of cancer

◦ quantify the risk associated with different

exposures and host factors

Promote insights into the mechanisms of

carcinogenesis

Assess efficacy of preventive measures

Investigate predictors of survival

CohortCase-ControlCross-Sectional (Prevalence)

Other

Descriptive Studies

◦ Incidence, mortality, survival

◦ Time Trends

◦ Geographic Patterns

◦ Patterns by Age, Gender, SES, Ethnicity

Analytic Studies

◦ Case-control

◦ Cohort

New Terminology

Incidence is a measure of the risk of developing some new condition / new

disease within a specified period of time.

Prevalence is the ratio of the total number of cases / disease in the total population in

a period of time .

Incidence Vs Prevalence

1

10

100

1000

San Francisco

Japan

China

Age (years/female)

Incidence is usually more useful than prevalence in

understanding the disease etiology: for example, if

incidence rate of population of a disease increases, then there is a risk factor that promotes the

incidence.

The five-year survival rate is a term for estimating the prognosis of a particular disease.

What is a cancer survival rate?Cancer survival rates or survival

statistics tell you the percentage of people who survive a certain type of cancer for a specific amount of time.

Understanding Cancer Survival : Mayo Cliniic

Cancer statistics often use an overall five-year survival rate.

For instance, the overall five-year survival rate for bladder cancer is 80 percent. That means that of all people diagnosed with

bladder cancer, 80 of every 100 were living five years after diagnosis.

5 years survival rate of breast cancer

WORLD CANCER STATISTIC WHO

INDONESIA

Cancer risk factor

Ionizing Non Ionizing

◦ Ultraviolet◦ Electromagnetic

4-Aminobiphenyl Bladder Arsenic Lung, skin Asbestos Lung, pleura,

peritoneum Benzene Leukemia Benzidine Bladder beta-Naphthylamine Bladder Coal tars and pitches Lung, skin Mineral oils Skin Mustard gas Pharynx, lung Radon Lung Soot, tars, and oils (polycyclic hydrocarbons) Lung, skin Vinyl chloride Liver Wood dusts (furniture) Nasal sinuses 

Helicobacter pylori increases risk of stomach cancer

Etiology, distribution, and control of disease in families and with inherited causes of disease in populations

Includes ◦ family studies◦ molecular epi studies w/ genetic components ◦ traditional cohort + case-control studies w/ family

history components

CDKN2A -- major melanoma susceptibility gene

Frequency of mutations varies in families◦ 2 cases <5%◦ 3 – 5 cases 20 – 24%◦ >6 cases 50%

Progress Report on Cancer Control in Canada, Health Canada

Increasing risk Reducing risk

Probable Excess weight/BMI Physical activity

Alcohol Aspirin

Family history *Family history * Hormone replacement therapy

Vegetables

Possible Tobacco smoking Oral contraceptives

Insulin/hyperinsulinaemia/related factors

Other NSAIDs

Calcium

Folate/folic acid

* Approximately 2-fold increase in risk to 1st-degree relatives

Little and Sharp, accepted.

Hormonal Factors◦ Early age at

menarche◦ Late age at

menopause◦ Multiparity◦ Late age at first full-

term pregnancy◦ OCs◦ HRT

Family history◦ BRCA1/BRCA2 – 5%◦ Other - ?

Post-menopausal obesity

Physical Activity (inverse association)

Alcohol use

Meat consumption Selenium (inverse association) Family history Androgens

HPV

http://www.york.ac.uk/depts/biol/units/cru/HPV%20and%20cancer.jpg

Electron micrograph showing HPV particles (red and green)

SmokingSmoking– OR 1.5-2.5OR 1.5-2.5

Tobacco control the priority Dietary modification - plant foods Avoid known carcinogens in

occupations and general environment Hepatitis B Vaccination Sex education for HIV, cervix cancer Promote physical exercise and weight

reduction Sun avoidance

• Use only effective strategies• Educate professionals and public• Base on Natural History of cancer• Screen at right ages and frequency• Maintain high quality• Ensure adequate facilities available• Organization

Prevention:• Tobacco control 30 years• Dietary modification 10-50 years

• Infection control 40 yearsScreening 10 yearsTreatment 5 years