Oncology
Cancer epidermiology
Etiology: causes of cancer (risk factors)
Life-time-risk cancer (85yrs)
Females: 38%
Males: 45%
Why cancer epidemiology?
To obtain knowledge about trends in incidence and survival/mortality after cancer in order to
a. Make informed decisions regarding health policy
b. Adequately evaluate clinical developments
Key epidemiological concepts
1. Prevalence
a. Number of people with cancer/ population at risk (at a certain moment in time)
b. Example: 5 year cancer prevalence at 1 january 2019 in NL: you look at all living
cancer patients who have been diagnosed in the previous 5 years in the NL
2. Incidence
a. Number of newly diagnosed cases of cancer/population at risk (at a certain time
period)
b. Example: incidence in 2018 in NL: you look at number of newly diagnosed cancer
cases in 2018 in NL
3. Mortality
a. T a certain time period
b. Can be described as
i. CR: crude rate number of new cases per 100 000 persons per year
, ii. ESR: European standardized rate number of new cases per 100 000 per
year, standardized for the age composition of Europe
iii. WSR: world standardized rate --? Number of new cases per 100 000 persons
per year, standardized for age composition of the world
4. Relative survival
a. The percentage of cancer cases alive at a certain time period after diagnosis )not
including those who died from other diseases (e.g. 5 year relative survival:
percentage of cancer cases who survived 5 years)
Why more stomach cancer in Asia
1. Helicobacter pylori
2. Food conservation (salt, smoke)
Why more liver cancer in Africa/Asia
1. Hepatitis B
2. Aflatoxin (present in peanuts and soy: fungi who grows in it)
Why more cervix cancer in south America/Africa
1. Human papillomavirus
Most frequent invasive tumours in Netherlands
Males:
1. Prostate
2. Skin excl bcc
3. Colorectal
4. Lung
Female
1. Breast
2. Skin excl bcc
3. Colorectal
4. Lung ‘
Cancer deaths in Netherlands: lung cancer due to smoking!
Etiology
(risk factors)
Most important risk factor: Age!
Why? Because time is needed for accumulation of damage to daughter cells/ mutations in regulatory
genes
- spontaneous
- Chemical substances
- Radiation
- Viruses
+ repair tools less effective
+ less control by micro-environment
Protective tools against damage accumulation
- Repair of blueprint (DNA repair)
, - Clean suicide (apoptosis)
- Mitosis stops (senescence)
Grey pressure (number 65+ / number 20 – 64): more and more older people influencing cancer
incidence: increase
(also increases survival rates, but still increase in cancer deaths each year)
So, there is an increase of people living with cancer which is an enormous public health problem
- Double ageing phenomenon
- Better survival because of
o Early detection
o Improved treatment
- More expensive health care
o Diagnosis
o treatment
Important: focus on prevention
In order to be able to focus on prevention: you need to know the causes of cancer
How do you identify causes of cancer?
1. Accidental finding/ keep alert
a. Nuns: breast cancer related to hormone exposure
b. Doctor: skin cancer after radiation on hands (x-ray)
c. Watch-making (martland): painting watches with radium (wetting point of pensil
with mount) led to bone cancer
d. Recent examples:
i. Chrome-6 in paint in army
ii. GenX in drinking water
iii. TATA steel, 50% more lung cancer in people living in area around TATA steal
2. Systematic counting / trends
a. Eye cancer: one vs two hits needed
i. Two hits: unilateral (both heritable and spontaneous)
ii. One hit: bilateral (one genetic hit)
b. Stomach cancer
i. Differences in different parts of world in risk of stomach cancer
ii. migrant studies: they identified life style factors were important
c. Melanoma
i. Increase in melanoma incidence over time: why? Due to sun bathing
3. Focussed research: human observational or model experimental
a. Case control study: identifying cases + finding
suitable controls
i. Questionary: asking about past behaviour
ii. Problem: people can remember their past
behaviour different
b. Prospective cohort study: starting with healthy
people
i. Again questioning: but then look over time
at exposed compared to non-exposed (and
then at diseased not diseased)
, ii. Advantage: no bias between case and disease (because when the
questionary is started, there is no disease yet)
iii. Disadvantage: large sample size, as you have to wait till cancer develops
4. Exploration
Smoking and cancer
Related to cancer of
1. Lung (95%)
2. Bladder (50%)
3. Stomach
4. Intestine
5. Oesophagus
6. Mouth
7. Pancreas
But also, cardiovascular diseases and impotence
Tobacco carcinogens, biomarkers and tabacco induced cancer
Nicotine: addictive agent of cigarettes
Carcinogens, can be
- Excreted
- Metabolic activation which will lead to mutations and other changes
- Receptor binding leading to AKT and PKA activation
Or, co-carcinogens and tumour promotors: leads to PKC and AP1 activation and enhanced
carcinogenicity
Prevelance by healthy diet, body weight, and physical activity
33% of cancers, but depending on cancer type and country
Third expert report: WCRF report a systematic literature review containing
1. Descriptive studies
2. Ecological studies
3. Migrant studies
4. Experimental studies
5. Case-control studies
6. Cohort studies
7. Randomized controlled trials
They gave a summary of strong evidence on diet, nutrition, physical activity and the
prevention of cancer
Grading the evidence
- Convincing
o Strong and unlikely to change in future
o No explained heterogeneity
o At least 2 independent cohort studies
o Good quality studies that account for error
o Dose response
o Robust evidence from laboratory studies
- Probable
Cancer epidermiology
Etiology: causes of cancer (risk factors)
Life-time-risk cancer (85yrs)
Females: 38%
Males: 45%
Why cancer epidemiology?
To obtain knowledge about trends in incidence and survival/mortality after cancer in order to
a. Make informed decisions regarding health policy
b. Adequately evaluate clinical developments
Key epidemiological concepts
1. Prevalence
a. Number of people with cancer/ population at risk (at a certain moment in time)
b. Example: 5 year cancer prevalence at 1 january 2019 in NL: you look at all living
cancer patients who have been diagnosed in the previous 5 years in the NL
2. Incidence
a. Number of newly diagnosed cases of cancer/population at risk (at a certain time
period)
b. Example: incidence in 2018 in NL: you look at number of newly diagnosed cancer
cases in 2018 in NL
3. Mortality
a. T a certain time period
b. Can be described as
i. CR: crude rate number of new cases per 100 000 persons per year
, ii. ESR: European standardized rate number of new cases per 100 000 per
year, standardized for the age composition of Europe
iii. WSR: world standardized rate --? Number of new cases per 100 000 persons
per year, standardized for age composition of the world
4. Relative survival
a. The percentage of cancer cases alive at a certain time period after diagnosis )not
including those who died from other diseases (e.g. 5 year relative survival:
percentage of cancer cases who survived 5 years)
Why more stomach cancer in Asia
1. Helicobacter pylori
2. Food conservation (salt, smoke)
Why more liver cancer in Africa/Asia
1. Hepatitis B
2. Aflatoxin (present in peanuts and soy: fungi who grows in it)
Why more cervix cancer in south America/Africa
1. Human papillomavirus
Most frequent invasive tumours in Netherlands
Males:
1. Prostate
2. Skin excl bcc
3. Colorectal
4. Lung
Female
1. Breast
2. Skin excl bcc
3. Colorectal
4. Lung ‘
Cancer deaths in Netherlands: lung cancer due to smoking!
Etiology
(risk factors)
Most important risk factor: Age!
Why? Because time is needed for accumulation of damage to daughter cells/ mutations in regulatory
genes
- spontaneous
- Chemical substances
- Radiation
- Viruses
+ repair tools less effective
+ less control by micro-environment
Protective tools against damage accumulation
- Repair of blueprint (DNA repair)
, - Clean suicide (apoptosis)
- Mitosis stops (senescence)
Grey pressure (number 65+ / number 20 – 64): more and more older people influencing cancer
incidence: increase
(also increases survival rates, but still increase in cancer deaths each year)
So, there is an increase of people living with cancer which is an enormous public health problem
- Double ageing phenomenon
- Better survival because of
o Early detection
o Improved treatment
- More expensive health care
o Diagnosis
o treatment
Important: focus on prevention
In order to be able to focus on prevention: you need to know the causes of cancer
How do you identify causes of cancer?
1. Accidental finding/ keep alert
a. Nuns: breast cancer related to hormone exposure
b. Doctor: skin cancer after radiation on hands (x-ray)
c. Watch-making (martland): painting watches with radium (wetting point of pensil
with mount) led to bone cancer
d. Recent examples:
i. Chrome-6 in paint in army
ii. GenX in drinking water
iii. TATA steel, 50% more lung cancer in people living in area around TATA steal
2. Systematic counting / trends
a. Eye cancer: one vs two hits needed
i. Two hits: unilateral (both heritable and spontaneous)
ii. One hit: bilateral (one genetic hit)
b. Stomach cancer
i. Differences in different parts of world in risk of stomach cancer
ii. migrant studies: they identified life style factors were important
c. Melanoma
i. Increase in melanoma incidence over time: why? Due to sun bathing
3. Focussed research: human observational or model experimental
a. Case control study: identifying cases + finding
suitable controls
i. Questionary: asking about past behaviour
ii. Problem: people can remember their past
behaviour different
b. Prospective cohort study: starting with healthy
people
i. Again questioning: but then look over time
at exposed compared to non-exposed (and
then at diseased not diseased)
, ii. Advantage: no bias between case and disease (because when the
questionary is started, there is no disease yet)
iii. Disadvantage: large sample size, as you have to wait till cancer develops
4. Exploration
Smoking and cancer
Related to cancer of
1. Lung (95%)
2. Bladder (50%)
3. Stomach
4. Intestine
5. Oesophagus
6. Mouth
7. Pancreas
But also, cardiovascular diseases and impotence
Tobacco carcinogens, biomarkers and tabacco induced cancer
Nicotine: addictive agent of cigarettes
Carcinogens, can be
- Excreted
- Metabolic activation which will lead to mutations and other changes
- Receptor binding leading to AKT and PKA activation
Or, co-carcinogens and tumour promotors: leads to PKC and AP1 activation and enhanced
carcinogenicity
Prevelance by healthy diet, body weight, and physical activity
33% of cancers, but depending on cancer type and country
Third expert report: WCRF report a systematic literature review containing
1. Descriptive studies
2. Ecological studies
3. Migrant studies
4. Experimental studies
5. Case-control studies
6. Cohort studies
7. Randomized controlled trials
They gave a summary of strong evidence on diet, nutrition, physical activity and the
prevention of cancer
Grading the evidence
- Convincing
o Strong and unlikely to change in future
o No explained heterogeneity
o At least 2 independent cohort studies
o Good quality studies that account for error
o Dose response
o Robust evidence from laboratory studies
- Probable
