11: Epidemiology of Cancer

Question 1

Explain the trend of cancer incidence rates in western countries

Answer 1

Overall: it used to increase, now further followed by a plateau of cases in many countries (might even decrease in some wetern countries)!

Question 2

What are the reasons for the change in incidence of cancer in western countries?

Answer 2

The change (increase/plateau, might even decrease) is predominantly due to

• increased sensitivity of diagnostic test–> more and earlier diagnosis
• increased access to healthcare
• ageing
• achnge of risk factor exposure (e..g now: decrease in smoking)

Question 3

What is the trend of cancer incidences in developing/threshold contries?

Answer 3

It increases

• due to more access to healthcare (+ more testing)
• ageing
• not diing from other causes

Question 4

What is the trend in cancer mortality in western countries?

Why?

Answer 4

It overall decreases due to

• earlier diagnosis
• better therapies

Question 5

What is the trend of cancer mortality in developing /non-western countries?

Answer 5

It increases

Question 6

How many percent of cancers are hereditary?

What is meant by that word?

Answer 6

Only 5-10% are hereditary

• people e.g. inhierit a defect TSG and only need one more hit to develop cancer

Question 7

What are the main environmental risk factors for cancer?

Answer 7

1. Smoking
2. Diet
   
   1. red meat consumption, processed meat and salt
   2. fibre
3. Alcohol
4. Obesity
   
   1. chronic inflammatory diseae
5. Occupation
6. Reproductive hormone

Question 8

What are the consequences of a western lifestyle in regards to cancer

Answer 8

• Causes
  
  • Energy dense diet, rich in
    
    • • fat,
    • • refined carbohydrates
    • • animal protein
  • Low physical activity
  • Smoking and drinking
• Consequences:
  
  • Greater adult body height
  • Early menarche
  • Obesity
  • Diabetes
  • Cardiovascular disease
  • Hypertension

Question 9

What is the role of infections in cancer?

Answer 9

16% cases of cancer likely caused by infectious agents worldwide

• 25% in Africa
• <10% in Europe (1 in 33 in UK)

Question 10

Explain the methods of how epidemiological studies establish cancer causation

Answer 10

A lot is done via Migrant studies

• People migrating from a low/high risk are to the opposite area
• If there is a mainly genetic risk: risk for individual would not change
• If they are environemtal risks: risk adapts the one in new country

Question 11

What are the 5 cancers with the highes incidence in women worldwide?

Answer 11

1. Breast cancer
2. Colorectal cancer
3. Lung
4. Cervix Uteri
5. Thyroid

Question 12

What are the cancers with the highes mortality in women worldwide?

Answer 12

1. Breast
2. Lung
3. Colorectal
4. Cervical
5. Stomach

Question 13

What are the 5 cancers with the highest incidence among men worlwide?

Answer 13

1. Lung
2. Prostate
3. Colorectal
4. Stomach
5. Liver

Question 14

What are the 5 cancers most men die from worldwide?

Answer 14

1. Lung
2. Liver
3. Prostate
4. Colorectal
5. Stomach

Question 15

What are the 5 leading cancers in countries with high HDI? (incidence)?

Answer 15

1. Breast
2. Colorectal
3. Lung
4. Prostate
5. Bladder

Question 16

What are the 5 leading cancers in countries with high HDI? (mortality)

Answer 16

1. Lung
2. Colorectal
3. Pancreas
4. Breast
5. Stomach