1. Cancer epidemiology and Cancer registry
Lausanne-Part
Cancer epidemiology and Cancer registry
C. Sauvaget MD, PhD Scientist, Screening Group (SCR)

2. Definition of Epidemiology
Lausanne-Part
Definition of Epidemiology
Study of the distribution and determinants of diseases in human populations
Epidemiological studies have been categorized into 2 major groups:
Focus on distribution: descriptive epidemiology – burden, pattern
Focus on determinants: analytical epidemiology – causes, risk factors
Application: prevention, control

3. Descriptive Epidemiology
Lausanne-Part
Descriptive Epidemiology
Can be conducted with or without the knowledge of exposure
Pure descriptive epidemiology—no exposure data
Present rates by calendar year, cohort year of birth stratified by age, gender, race, disease subtype, geographic regions
Analytical ecological study-with exposure data
Correlation or regression at aggregate level

4. Example of ecological study
Lausanne-Part
Example of ecological study
Estimated daily consumption of fat per caput in and age-adjusted breast cancer incidence rates in women aged years in in 24 countries (reproduced, by permission of Oxford University Press, from Armstrong & Mann, ).
Dos Santos I. Cancer epidemiology, 1999, IARC publications

5. Role of Descriptive Epidemiology-1a
Lausanne-Part
Role of Descriptive Epidemiology-1a
Can provide tremendous insights into the aetiology –
Different racial groups living in same area with wide differences in disease rate -- possibility of genetic susceptibility
Testicular cancer (Whites: 6/100,000; Blacks: 0.7/100,000)
Same racial group living in different areas with similar disease rate -- possibility of genetic susceptibility
Testicular cancer (Blacks: /100,000)

6. Role of Descriptive Epidemiology-1b
Lausanne-Part
Role of Descriptive Epidemiology-1b
Can provide tremendous insights into the aetiology
Same racial group living in different areas with wide differences in disease rate — possibility of environmental exposures
Different occupational groups have major differences in disease rate — importance of occupational exposures
Different religious groups having different rates — importance of lifestyle factors
Chinese Han, and other minorities

7. Example of environmental factor
Lausanne-Part
Example of environmental factor
Age-adjusted incidence rates of female breast cancer for USA residents ( ) by birthplace and age at migration, and for Jordan ( ) (reproduced, by permission of Churchill Livingston, from Shimizu et al., 1991)
Dos Santos I. Cancer epidemiology, 1999, IARC publications

8. Example of occupational factor
Lausanne-Part
Example of occupational factor
Men occupation class and risk of incident cancer ( , n= )
Melchior et al. Cancer causes and control 2005;16:

9. Role of Descriptive Epidemiology-2
Lausanne-Part
Role of Descriptive Epidemiology-2
Disease incidence trends over time
Point to an altered influence of risk factors in the population:
Increase exposure to UVR due to:
»Increase outdoor activities
»Change in cloth patterns
»Increase use of suntan lamps
»Increase depletion of ozone layer
Increase in skin cancer

10. Time trend of cigarettes sales and lung cancer mortality
Lausanne-Part
Number of cigarettes per adult
Annual Age-std mortality rate from lung cancer
Kubik et al. Cancer 1995

11. Lausanne-Part
Annual age-adjusted incidence rates of cancers at selected primary sites in Finland: actual rates from 1953 to 1979 and predictions up to the year 2000 based on a statistical model which included age, period and cohort effects (reproduced with permission from Läärä, 1982)
Dos Santos I. Cancer epidemiology, 1999, IARC publications

12. Lausanne-Part
Age-standardised incidence of invasive cervical cancer and screening coverage rate: England,
National call-recall introduced 
Incidence of invasive cervical cancer
Screening coverage rate
Incidence rate/
Percentage
Sources: Cancer Research UK; Quinn et al., 1999; Willoughby et al., 2006

13. Proportion of cancers attribution to various risk factors
Lausanne-Part
Proportion of cancers attribution to various risk factors
Risk factors
Best estimate
Range
Tobacco 30
25-40
Alcohol 3
2-4
Hazardous diet, physical inactivity 35
10-70
Medicines & medical procedures 1
0.5-3
Infection* 10
1-?
Reproductive factors 7
1-13
Occupation 4
2-8
Pollution 2
1-5
Geophysical factors
* HBV, HCV, HPV, EBV, Helicobacter Pylori, HIV, schistosomiasis…
Doll and Peto. JNCI 1981,66:

14. Effect of Hepatitis B vaccination on incidence of liver cancer in Taiwan
Lausanne-Part
Chang et al. N Eng J Med 1997

15. Measures of occurrence of disease
Lausanne-Part
Measures of occurrence of disease
Denominator
Time period
Incidence
Prevalence
Risk

16. Measures of occurrence of disease
Lausanne-Part
Measures of occurrence of disease
Population at risk: The part of a population which is susceptible to a disease
Incidence: The number of new health events occurring in a defined population during a specified period of time
New cases /population at risk /time
Used to measure current disease activity
Allows comparison between areas with different populations
Ex. 100 subjects are followed for 1 year and 20 developed the disease => the incidence rate is 20 cases /100 person-years of observation
Prevalence: The proportion of individuals in a population at risk with a disease at a single point in time

17. Relationship between Incidence and Prevalence
Lausanne-Part
Prevalence is the number of new and existing cases divided by the total population (can be during a period of time or at a given point)
Prevalence = (New cases + existing cases) / Total population
Can be expressed as a percent
Can give a picture of disease burden within a population
Prevalence rate = incidence rate x average duration of disease
Incidence
Duration
Prevalence
Dead, cured, missed, etc.

18. Using routine data to measure disease occurrence
Lausanne-Part
Using routine data to measure disease occurrence
Dos Santos I. Cancer epidemiology, 1999, IARC publications

19. Lausanne-Part
Exposure and outcome-1
Definition
Measurement

20. Lausanne-Part
Exposure and outcome-1
* Does alcohol intake increase the risk of lung cancer?
Alcohol Lung cancer
(exposure) (outcome)
* Does hepatitis B vaccination protect against liver cancer?
Hepatitis B vaccine liver cancer

21. Lausanne-Part
Exposure and outcome-2
* Does alcohol intake increase the risk of lung cancer?
Alcohol Lung cancer
(exposure) (outcome)
Smoking
(confounder)

22. Exposure Nature Dose Time Source: Questionnaire Records Diaries
Lausanne-Part
Exposure
Nature
Dose
Time
Source:
Questionnaire
Self-administered
Personal interview
Records
Diaries
Biological measurement

23. Outcome Hospital records Cancer registration Death registry
Lausanne-Part
Outcome
Hospital records
Cancer registration
Death registry

24. Cancer registries http://ci5.iarc.fr/ http://globocan.iarc.fr/
Lausanne-Part
Cancer registries

25. Cancer Registry: Registration
Lausanne-Part
Cancer Registry: Registration
Cancer Registry
The office or institution which is responsible for the collection, storage, analysis and interpretation of data on persons with cancer.
Cancer registration
The process of continuing systematic collection of data on the occurrence, characteristics, and outcome of reportable neoplasm with the purpose of helping to assess (prevent) and control the impact of malignant disease in the community.

26. Cancer Registry 1. Population-based Cancer Registry
Lausanne-Part
Cancer Registry 1. Population-based Cancer Registry
All cases in a DEFINED population are registered
True (unbiased) profile of cancer in the community
incidence, stage distribution, survival, etc.
Calculation of incidence rates (because population at risk is quantified)
The main interest is for epidemiology and public health

27. Cancer Registry 2. Hospital-based Cancer Registry
Lausanne-Part
Cancer Registry 2. Hospital-based Cancer Registry
Records all cases of cancer treated in a given hospital
The population from which the cases come is not defined
The main interest is clinical care hospital administration

28. Basic information required and variable definitions
Lausanne-Part
Basic information required and variable definitions
Item no.
Item
The person
The tumour
Personal identification
Incidence date
Name
Most valid basis of diagnosis
Sex
Date of birth or age
Topography (site)
Demographic
Morphology (histology)
Address
Behavior
Ethnic group
Source of information

29. Most valid basis of diagnosis of cancer
Lausanne-Part
Most valid basis of diagnosis of cancer
Microscopic
1. Autopsy with concurrent
or previous histology
2. Histology of primary
3. Histology of metastasis
4. Cytology or haematology
Non-microscopic
5. Specific biochemical and/or
immunological tests
6. Exploratory surgery
7. Clinical investigation (X-ray, US…)
8. Clinical only
9. Death Certificate Only (DCO)
ICD-Oncology

30. Incidence and survival data
Lausanne-Part
Incidence and survival data
Provided by cancer registries thru the International Association of Cancer Registries (IACR)
Mostly regional (except Nordic countries)
Not always recent (generally 5-year delay): request time to be compiled and published.
Detailed information (site, histology, laterality, grade, stage)

31. Lausanne-Part
Coverage of cancer registration worldwide % of the population covered (around 2000)
40.0
99.0
19.0
7.1
7.9
When considering data of good quality (included in the latest volume for the Cancer Incidence in Five Continents series), these percentages are even lower: only 8% of the world is covered by “good, reliable” cancer registries.
13.0
82.0
16.5% total

32. Number of deaths from cancer
Lausanne-Part
Mortality data
Number of deaths from cancer
National level
Provided by the WHO
Recent and available for long time periods (1950 to 2008)
Limited number of cancers
Quality can be poor (under-reporting, incomplete coverage, high percentage of ill-defined causes of deaths)

33. Mortality data (WHO databank)
Lausanne-Part
Mortality data (WHO databank)
% of the population covered (around 2005)
98.0
100.0
100
9.0
13.8*
95.0
The coverage is better for mortality. However, the detail and the quality of the data (accuracy of the recorded cause of death and the completeness of registration vary substantially).
Note that there is quite no mortality information for Africa except in South Africa and Egypt (13% of total African pop)
76.5
33% total
*Egypt and South-African Republic

34. Lausanne-Part
Estimated age-standardised incidence rate per 100,000 Lung: male, all ages
1,095,186 cases in 2008
GLOBOCAN 2008
Ferlay J, Shin HR, Bray F, Forman D, Mathers C and Parkin DM. GLOBOCAN 2008, Cancer Incidence and Mortality Worldwide: IARC CancerBase No. 10 [Internet]. Lyon, France: International Agency for Research on Cancer; Available from:

35. Estimated age-standardised incidence rate per 100,000 Breast: all ages
Lausanne-Part
Estimated age-standardised incidence rate per 100,000 Breast: all ages
1,383,523 cases in 2008
GLOBOCAN 2008
Ferlay J, Shin HR, Bray F, Forman D, Mathers C and Parkin DM. GLOBOCAN 2008, Cancer Incidence and Mortality Worldwide: IARC CancerBase No. 10 [Internet]. Lyon, France: International Agency for Research on Cancer; Available from:

36. Population (2008): 640 million population
Less developed countries
Lausanne-Part
Population (2008): 640 million population
Males
319 million Population
3.7 million cases
2.7 million deaths
Females
321 million population
3.5 million cases
2.1 million deaths
Lung
Breast
Stomach
Cervix uteri
Liver
Colorectum
Oesophagus
Prostate
Corpus uteri
Ovary
Bladder
Leukaemia
Lip, oral cavity
Incidence
Mortality
(Thousands)
GLOBOCAN 2008

37. Lausanne-Part

38. Cancer epidemiology studies
Lausanne-Part
Cancer epidemiology studies
Descriptive studies
Observational studies
Experimental studies

39. Prevalence estimate Prevalence at time t1 = 2/10 = 0.20 = 20%
Lausanne-Part
Prevalence estimate
Prevalence at time t1 = 2/10 = 0.20 = 20%
Prevalence at time t2 = 3/8 = 0.38 = 38%
Incidence case
Dos Santos I. Cancer epidemiology, 1999, IARC publications

40. Person-years and incidence rate
Lausanne-Part
Person-years and incidence rate
Consider a hypothetical group of nine persons who were followed up from the beginning of 1980 to the end of Subjects joined the study at different points, as shown in Figure. Three subjects, (2), (6) and (7), developed the disease of interest during the study period and one, (4), was last contacted at the end of 1983.
Incidence rate = 3/32 = per person-year or 9.4/100,000 P-Yrs
Dos Santos I. Cancer epidemiology, 1999, IARC publications

41. Main types of epidemiological studies
Lausanne-Part
Intervention (experimental) studies
Clinical trials
Filed trials
Individual level
Aggregated level (community trials)
Observational (non-experimental) studies
Cohort studies
Case-control studies
Cross-sectional surveys
Routine-data-based studies
Aggregated level (ecological studies)

42. Randomized Control Trials
Lausanne-Part
Randomized Control Trials
Intervention
outcome+
Research cohort
outcome-
outcome+
Randomization
outcome-
No intervention
Research direction： What will happen in the future?

43. Prospective Cohort Study
Lausanne-Part
Prospective Cohort Study
Exposed
Disease
Cohort
No disease
Disease
No disease
Not exposed
Present
Future
Time
Research direction： What will happen in the future?

44. Case-control Study Case Control past present Time
Lausanne-Part
Interview
Review of medical records
Review of biological exams
How many people
were exposed?
Case
How many people
were not exposed?
How many people
were exposed?
Control
Selection of controls
is one of the most difficult problems in epid.
How many people
were not exposed?
past
present
Time
Research direction： What happened in the past?

45. Cancer Registry Types 1. Population-based cancer registry (PBCR)
Lausanne-Part
Cancer Registry
Types
1. Population-based cancer registry (PBCR)
2. Hospital-based cancer registry
3. Pathology registry

46. Cancer Registry 3. Pathology Tumor Registry
Lausanne-Part
Cancer Registry 3. Pathology Tumor Registry
Collects information from one or more laboratories on histologically diagnosed cancers
The population from which the tumour tissue has come is not defined
The information
- has high diagnostic quality
- but is difficult to generalize

47. HOSPITAL CANCER REGISTRY Additional variables
Lausanne-Part
HOSPITAL CANCER REGISTRY Additional variables
Contact details
Admission + Discharge dates
Hospital referred from , to
Physicians (treating, following)
Diagnostic procedures
Extent of disease
Treatment details (first, subsequent)
Outcome (recurrence)
Follow - up

48. Accessible thru the Internet or using a Windows-based PC software
Lausanne-Part
The results are presented for 170 countries of the world, plus build-in areas (six WHO regions, more and less developed countries and the world)
Data available for 27 major cancers, for men and women, and for 5 age groups: 0- 14,15-44,45-54,55-64,65+
Accessible thru the Internet or using a Windows-based PC software
If there are no data, the country specific rates are those of the corresponding region (calculated from the other countries for which estimates could be made).

49. Cancer – worldwide burden
Lausanne-Part
Cancer – worldwide burden
7 million Deaths
11 million New Cases
25 million Living with Cancer

50. New cancer cases and deaths, World 2002
(10.8 million cases/6.7 million deaths)
Lausanne-Part
Males
5.8 million cases
3.8 million deaths
Females
5.0 million cases
2.9 million deaths
Lung (1.35/1.18)
Breast (1.15/0.41)
Colon/Rectum (1.0/0.53)
Stomach (0.93/0.70)
Prostate (0.68/0.22)
Liver (0.63/0.60)
Cervix uteri (0.49/0.28)
Oesophagus (0.41/0.34)
Bladder (0.35/0.14)
Non-Hodgkin lymphoma (0.30/0.16)
Leukaemia (0.28/0.20)
Oral cavity (0.27/0.12)
Pancreas (0.23/0.22)
Kidney (0.21/0.11)
Ovary (0.20/0.12)
Incidence
Mortality
(Thousands)