cancer 11

Question 1

what are the leading causes of death in the world?

Answer 1

• Ischaemic heart disease and stroke lend to the highest global causes of death
• not cancer

Question 2

how have CVS death numbers changed?

how have cancer death numbers changed?

Answer 2

• Death rates from CVS disease have dropped over the years
• Death rates from cancer have remained stable/increased-slightly over the years.

Question 3

compare cancer in developed and undeveloped countries?

Answer 3

Developed countries have a greater incidence of cancer than undeveloped countries.

Question 4

most common male cancers?

Answer 4

• prostate and lung cancers are the most common cancers

Question 5

most common female cancers?

Answer 5

• breast and cervical cancers are the most common cancers

Question 6

why might cancer incidence show geographical variation?

Answer 6

• Melanoma is most common in Australia and stomach cancer is most common in Japan.
• Australia might have high melanomas due to exposure to the sunlight and Australian people often have fair skin as they were originally from the UK
• Japan has high rates of stomach cancer due to infection with Helicobacter pylori bacteria as well as a diet factor

Question 7

why has colorectal cancer increased in japan?

Answer 7

• there has been a shift in diet from fish and vegetables to red meat
• this is reflected in an increase in colorectal cancer in japan

Question 8

why are migrant studies useful to look at cancer incidence in different countries?

Answer 8

• it is useful to look at migrants and see if their risk for developing cancer changes when they move to a new country eg. when the Japanese moved to Hawaii their risk for stomach cancer decreased down to American levels
• genetic susceptibility is important
• the environment also makes a difference

Question 9

how is the incidence of cancer changing in the world?

Answer 9

• increasing in both low and high-income countries
• increase in high-income countries may be due to the introduction of screening programs
• increase in low income countries may be due to increasing ageing

Question 10

how is mortality changing in high and low income countries?

Answer 10

• Mortality is decreasing in high-income countries but NOT low-income
• mortality is decreasing in high income countries due to better treatment and earlier diagnosis

Question 11

what percentage of cancer is genetic?

Answer 11

• 5-10% , very few

Question 12

give examples of when a hereditary condition predisposes to cancer :

Answer 12

Question 13

what are the common risk factors of cancer?

Answer 13

• Smoking
• diet
• infection
• reproductive hormone
• alcohol
• occupation

ranked highest risk to lowest risk

Question 14

what percentage of cancers are preventable?

Answer 14

45% (men) and 40% (women) of cancers could have been prevented by reducing risk from environmental factors

Question 15

how much does smoking increase the risk of cancer?

Answer 15

• smoking contributes towards 30% of cancer death
• increases risk for >15 cancers
• 90% (men) and 80% (women) of lung cancer causes.

Question 16

how does diet increase the risk of cancer?

Answer 16

• colorectal cancer chance increased with low fibrous diet.
• red processed meat increases risk of colorectal cancer

Question 17

how does alcohol increase the risk of cancer?

Answer 17

• synergistic with alcohol intake
• the mechanism is poorly understood
• it is associated with liver, oral cavity, pharynx, larynx and oesophageal cancer

Question 18

what are the recommendations for dietary prevention of cancer?

Answer 18

• Be lean without being underweight.
• Be physically active for at least 30 minutes a day.
• Avoid sugary drinks.
• Eat a variety of fruit/veg.
• Limit consumption of red meat (<500g/week) and avoid processed meat.
• Limit alcoholic drinks.
• Limit consumption of salty foods.

Question 19

what might increase the risk of breast cancer?

Answer 19

• Sex steroids can increase cancer risk.

Question 20

what percentage of cancer is caused by infectious causes?

Answer 20

16% of cancer is from an infectious cause (25% in Africa and <10% in EU).

for example :

• HPV (cervix cancer)
• EBV (Hodgkin’s/Burkett’s Lymphoma)
• HCV/HBV (liver cancer)
• H. pylori (stomach cancer).

Question 21

read through the ibook key points:

Answer 21