cancer - a public health issue. epidemiology the study of the patterns, causes, and effects of...

CANCER

- a public health issue

epidemiology

• the study of the patterns, causes, and effects of health and disease conditions in defined populations

• informs policy decisions and evidence-based medicine – identifies risk factors for disease– targets for prevention

• Epidemiologists help with study design, collection and analysis of data, and interpretation and distribution of results

Canadian Cancer Statistics 2013

Canadian Cancer Statistics 2013

Canadian Cancer Statistics 2013

Canadian Cancer Statistics 2013

Cancer in Canada

Cancer Risk FactorsThere are many known risk factors for cancer:

• Tobacco Use (30%)• almost 30% of all fatal cancers in Canada

• major cause of lung cancer

• Poor Diet/Obesity/ Lack of Exercise (30%)• one with a high proportion of dietary fat, about 20% of

fatal cancers

• Colon and prostate cancers are associated with diets high in fat

http://www.youtube.com/watch?v=aUaInS6HIGo&feature=c4-overview-vl&list=PL4TcyUrQ3YhJ4X5kajWcx9myxoLfx_zt-

• Other Risks (30%)• workplace hazards

• family history

• alcohol use

• reproductive factors

• sexual activity

• sunlight/ ionizing radiation

• drugs

Reducing your risk• Live well. Make healthy choices.

• Be a non-smoker and avoid second-hand smoke.

• Keep a healthy body weight. Be active and eat well.

• Know the risks of alcohol.

• Protect your skin.

But…What’s causing cancer?

• A look inside the nucleus

• Multi cellular organisms = billions of cells• cells need to divide and copy themselves for a variety of

reasons.

For example:

– cells wear out and need to be replaced

– new cells allow the body to repair damaged tissue

– new cells allow the body to grow

Cell Division

- The most common form of cell division is mitosis

- Occurs in all body cells and is used for growth and repair

- cell makes an exact copy of itself and splits into two new cells

- Each cell contains an exact copy of the original cell’s DNA: this is the reason why all the cells in an organism are genetically identical

• Cell division occurs through a copying of its genetic information

• At the end of mitosis you end up with two identical (daughter) cells, each carrying the same DNA

http://www.youtube.com/watch?v=Q6ucKWIIFmg

But…what’s so important about DNA?

• In a cell all functions are carried out by proteins: control of cell reproduction, production of energy, production of hormones, production of digestive enzymes, etc.

• DNA contains genes: the blueprints for those proteins

• Each gene is an assembly guide (think IKEA) on how to put the protein together

DNA RNA protein

Central Dogma of Molecular Biology

DNA RNA protein

• If there is a mistake (mutation) in the blueprint, in the DNA, there will be a mistake in the protein

• Most times the cell will detect the mistake and die:

Figure 9.21 Apoptosis: Programmed Cell Death

When cell division goes wrong

• Cell division is tightly controlled by genes inside the nucleus.

• Special genes, called oncogenes, stimulate cell division

• If through a mutation an oncogene is irreversibly switched “on” it can cause uncontrolled cell division

CANCER = uncontrolled cell division

• Cells divide, divide, and divide…

www.microscopyu.com/moviegallery/livecellimaging/3t3/index.html

http://www.youtube.com/watch?v=IeUANxFVXKc

tumour

• The uncontrolled growth of cells forms a lump called a tumour.

– Some tumours are benign and may not cause any problems.

– Others are malignant. They can invade into other body tissues and cause severe damage. It is these malignant tumours that we call cancer.

• There are over 200 different types of cancer and they can occur anywhere in the body.

Cancer Treatments

1. Surgery- Effective for tumours in a defined area, often the first

treatment

1. Chemotherapy- Medication used to target and kill quickly-dividing

cancer cells: some prevent new cells from splitting apart, while others stop the production of new DNA

2. Radiation therapy- high-energy radiation is aimed at the growing tumour

to damage its DNA

3. Some combination

• http://www.hhmi.org/biointeractive/cancer/angiogenesis.html

What do you think?

A new genetic screening test for some cancers could allow for the identification of people who are at higher risk. Even if the test is positive, the person may never develop cancer. Do you think such a test should be available and if so, should it be publicly funded?

What do you think?

Certain cancer are linked to lifestyle choices (i.e. smoking), some people think that public health care dollars should not support the treatment of these types of cancers (at least not 100%) and that there is a certain degree of personal choice and responsibility.