Cancer Epidemiology

Question 1

Describe Cancer Incidence & Mortality compare it with the highest global cause of death, state gender differences

Answer 1

• Ischaemic heart disease and stroke lend to the highest global causes of death (not cancer).
  
  • Death rates from CVS disease have dropped over the years.
  • Death rates from cancer have remained stable/increased-slightly over the years.
• Developed countries have a greater incidence of cancer than undeveloped countries.
• Males – prostate and lung cancers are the most common cancers.
• Females – breast and cervix uteri cancers are the most common cancers.
• Cancer incidence can show a geographical variation:
  
  • I.E. Melanoma is most common in AUS/NZ and colorectal cancer is most common in Japan.
• The five major forms of cancer contributing to worldwide mortality are lung, stomach, liver, colorectal and breast

Question 2

State how Migration affects cancer incidence

Answer 2

to study cancer incidence:

• Rapid change in risk following migration à lifestyle and environmental factors act late in carcinogenesis. (it is not genetic, cause genetic would take longer to show)
• Slow change à exposures early in life are more relevant.
• Persistence of rates à genetic susceptibility is important in determining risk.(stomach cancer is not inherited)

Graph shows that people born in japan get the most stomach cancer as people born in Hawaii and elsewhere have a lower incidence.

Question 3

Describe the incidence of Cancer for both highi-income and low income countries, how can screening influence that, what happens in mortality?

Answer 3

Incidence is increasing for common cancer sites in both high-income (with plateau/decrease) and low-income countries – effects of earlier diagnosis, screening and changes in risk factors.

• Rapid increases in incidence may be due to the introductions of official screening procedures.
  
  • High income countries tend to show an increasing and then rapid increase followed by a plateau of cancer incidence due to introduction of screening procedures. (the early screenings might find an intermidieaty phase that could have not developes(mamography))
• Mortality is decreasing in high-income countries but NOT low-income (earlier diagnoses and better therapies)
  
  • Total burden of cancer is increasing because of demopgraphic changes( population size and ageing population) and westernization of lifestyles (it is increasing because in therid world countries the mortality of infectious studies is not decreased)
  • The continuing upward trend in the cancer burden is mainly a result of increasing average life-span, but unhealthy lifestyle is also a major factor

Question 4

What are the Causes of Cancer

Answer 4

• They can have a hereditary inclination (5-10% of cases).
• Smoking, diet, infection, reproductive hormone, alcohol, occupation (order of attributive risk highest to lowest).
  
  • 45% (men) and 40% (women) of cancers could have been prevented by reducing risk.
  • Smoking – it causes 30% of cancer death, it increases risk for >15 cancers, results in 90% (men) and 80% (women) of lung cancer causes.

Question 5

How does Anthropometry influence the Causes of Cancer, which are the conditions that must exist to reduce cancer risk?

Answer 5

Anthropometry – study of measurements and proportions of the human body: obesity is an inflammatory disease that causes chronic inflammation which increases risk of cancer d

• World cancer research fund guidelines for dietary prevention:
  
  • 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.
• Breast cancers:
  
  • Sex steroids can increase cancer risk.
• Westernisation of lifestyle (more energy-rich diets, low physical diets, etc.) can promote cancer.
• Infectious causes of cancer - ~16% of cancer is from an infectious cause (25% in Africa and <10% in EU).
  
  • E.G. HPV (cervix cancer), EBV (Hodgkin’s/Burkett’s Lymphoma), HCV/HBV (liver cancer), H. pylori (stomach cancer).

Question 6

State how many people are living with cancer, how many cases are new each year and how many die each year

Answer 6

• There are approximately 14 million new cases of cancer every year and these diseases kill approximately 8 million people worldwide every year.
• Approximately 33 million people worldwide are living with cancer (within 5 years of diagnosis).
• In the developed world, over the last 20 years’ substantial increases in the five-year survival rates have been achieved for breast and prostate cancer among the major cancers.
• For other cancers, that of the lung, little therapeutic progress has been made over the last 20 years

Question 7

Describe the Western Lifestyle and state the consequences it has :

Answer 7

1. Fat
2. refined carbohydrates
3. animal protein
4. Low physical activity
5. Smoking and drinking

Consequences:

1. Greater adult body height
2. Early menarche
3. Obesity
4. Diabetes
5. Cardiovascular disease
6. Hypertension
7. Cancer

Question 8

Describe the main infectious agents that can cause cancer worldwide

Answer 8

Question 9

State the factors that incidence is dependent on:

Answer 9

1. Age
2. Common environmental causes
3. Geographical variation and secular trends

There are several well defined risk factors for cancer, including smoking, diet and alcohol consumption.

Question 10

PSA

Answer 10

can be testerd from DRE (Digital Rectum Examination)

Prostate Specific Antigen: protein that is invokves in giviing you the normal consistency of semen.

It is normally found in the prostate but it is never in the blood

It could be because of trauma (bicycle, catheter insertion), or because of beigning hypertrophy

Enrlaged prostate makes it more difficult to urinate

Back pain could be of a metastasis (cause the vessels go ont he back)

you have to sample from many areas cause you need to get all the info

1st is the sensitive screening

2nd is specific test (invasive and more expensive)

Prostate tends to metastsize to bones of the spine and along the pelvis, there are certain receptors etc that make it more easy to adhere

Cancer cells produces lots of glucose and therefore you look for highly metabolic region, seen in pet SCAN

Effects of surgery: there is effect of the nerves aroinf the sphincter–> akratia, erectile dysfanction

Another way of a LOCALISED tumour would be radiotherapy

More men die WITH prostate rather than BY prostate cancer

LHRH: chronic and desintizes =, supression of the LH production and therofore testicular testoteron production (testosteron stimulates growth on testes, we do that to reduce the promoting signal)

glutamate: anti-adrogen: