Cancer - epidemiology

Question 1

How have the death rates from cancers changed over the years

Answer 1

Remained stable/increased slightly

Question 2

What are the most common cancers for males and females

Answer 2

Males - Prostate and lung

Females - Breast and cervix uteri

Question 3

Give an example of geographical variation in cancer incidence

Answer 3

Melanoma is most common in Australia and New Zealand where there are fair skinned people in sunny climate
Colorectal cancer is most common in Japan

Question 4

What do migrant studies show

Answer 4

• A rapid change shows lifestyle and environment factors act late in carcinogenesis
• A slow change shows exposures early in life are more relevant
• Persistence of rates shows that genetic susceptibility is important in determining risk

Question 5

Why is cancer incidence increasing

Answer 5

Cancer incidence is increasing in both high income and low income countries due to improved diagnosis and screening
- High income countries tend to see a plateau or decrease shortly after this rise

Question 6

How is cancer mortality changing

Answer 6

Cancer mortality is decreasing in high income countries but not in low income countries

Question 7

List some causes of cancer

Answer 7

• Hereditary inclination (5-10% of cases)
• Other causes from highest to lowest order of attributive risk
• Smoking
• Diet
• Infection
• Reproductive hormone
• Alcohol
• Occupation

Question 8

What cancers does alcohol cause

Answer 8

Synergistic with tobacco but mechanism is poorly understood

Also associated with liver, oral cavity, pharynx, larynx and oesophageal cancer