Epidemiology of cancer

Question 1

How have mortality rates from cancer changed?

Answer 1

They’ve remained stable

Question 2

How do cancer incidence rates vary depending on level of development of a country?

Answer 2

Developed countries have a higher incidence of cancer

Question 3

Why is melanoma of higher prevalence in Australia than china?

Answer 3

Higher exposure to UV radiation in Australia

Many fair skinned people in Australia, more susceptible to mutation

Question 4

Why is lung cancer more prevalent in Eastern Europe than Western Africa?

Answer 4

Higher incidence of tobacco smoking in Eastern Europe

Question 5

How can we test whether genes or environment have more of an influence on cancer incidence?

Answer 5

Migrant studies

Question 6

If cancer was caused by environmental factors what would be observed?

Answer 6

Migrants from low risk area moves to a high risk areas

Their risk + incidence of cancer increases due to changes in exposure

Question 7

Describe a migrant study that demonstrated the environment majorly influenced cancer incidence

Answer 7

Japanese had high incidence of stomach cancer
Those who remained had high risk
Hawaiians had low incidence of stomach cancer
Japanese who migrated to Hawaii had incidence equal to Hawaiians within 2 generations

Question 8

What is the trend of cancer incidence in developed and less developed countries?

Answer 8

Developed: Increased, but now plateux

Less developed: Increasing

Question 9

What explains the trend of cancer incidence in developed and less developed countries?

Answer 9

Introduction of screening programmes
Increased accessibility to healthcare
Changes in exposure to risk factors (e.g. less popular to smoke now)

Question 10

What is the trend of cancer mortality in developed and less developed countries?

Answer 10

Developed: Decreasing

Less Developed: Not decreasing

Question 11

Why is the total cancer burden increasing?

Answer 11

Demographic changes (ageing populations, increasing populations)
Westernisation of lifestyles

Question 12

What % of cancers are due to hereditary causes?

Answer 12

5-10%

Question 13

List 4 main risk factors for cancer

Answer 13

Smoking
Diet
Alcohol
Infection

Question 14

Had risk factors been reduced to the optimal levels, how many cancers could have been prevented?

Answer 14

40-45%

Question 15

How many cancer deaths are caused by smoking?

Answer 15

30%

Question 16

How many lung cancer deaths are caused by smoking?

Answer 16

80-90%

Question 17

What dietary factor increases risk of colorectal cancer?

Answer 17

Low intake of fibre

Question 18

What synergism of risk factors largely increase risk of oesophageal/ laryngeal cancers?

Answer 18

Tobacco

Alcohol

Question 19

Which cancers are associated with obesity?

Answer 19

Post-menopausal breast
Colon
Pancreatic
Endometrial

Question 20

What are the guidelines for dietary prevention of cancer?

Answer 20

Be lean
Be active
Avoid sugary drinks/ energy dense foods
Plant based diet
Limit red meat
Limit alcohol
Limit salt 
Don't use supplements

Question 21

How can sex steroids influence cancer risk?

Answer 21

Increase risk e.g. Breast cancer

Question 22

What are the key factors influencing incidence of cancer?

Answer 22

Age
Common environmental causes
Geographical variation + secular trends

Question 23

How many new cases of cancer per year and how many deaths caused by cancer per year?

Answer 23

New cases: 14 mil

Deaths: 8 mil

Question 24

What are the 5 major forms of cancer contributing to mortality?

Answer 24

Lung
Stomach
Liver
Colorectal
Breast

Question 25

What are the 5 most common cancers?

Answer 25

Lung 
Breast
Colorectal
Prostate 
Skin

Question 26

What is the most common cancer in males and females respectively?

Answer 26

Males: Lung
Females: Breast