a) What is cancer?

Cancer is a growth that invades tissue without control and has a tendency to spread to new sites. By far, the most common cause of respiratory tract cancers is smoking (i.e., in 90% of cases). (see slides k, l, m, n, o)

b) How does smoking cause mouth, throat and lung cancer?

1) There are over 400 poisons in tobacco smoke and 43 of them are known to cause can-cer. These carcinogens (mostly in the tar) repeatedly damage cells in the mouth, throat and lungs when the smoke is inhaled; 2) in time, a few damaged cells reprogram their DNA and genetically mutate to cancer cells; 3) unlike normal cells, cancer cells grow without control, invading and destroying more and more surrounding tissue; 4) cancer cells can also break away from the original tumor and travel through the body to form new tumors in distant sites such as the brain, bone and liver. They then grow without control at these new sites. This is called metastasis.

c) How do you know if someone has mouth, throat or lung cancer? Can you find
examples in the Video?

1) Willy Thornton: mouth cancer (see Video Script pg 42).
2) Jerome Brown: throat cancer (see Video Script pg 43).
3) Claude Levy: lung cancer (see Video Script pg 44).

10. Surgeon General's Warning: Smoking causes emphysema

a) What is emphysema?

Emphysema is a pulmonary condition characterized by over distention and destruction of
the air sacs in the lungs. This causes labored breathing and severe shortness of breath. By
far, the most common cause of emphysema is smoking (90% of cases). (see slides p, q)

b) How does smoking cause emphysema?

1) toxic chemicals (poisons) in inhaled tobacco smoke cause damage and inflammation in the air sacs of the lung; 2) air sacs lose their elasticity and their walls rupture; 3) air that flows into them can't flow out easily and becomes trapped; 4) the end result is large air spaces filled with trapped, stagnant air which cannot be exhaled.

c) How do you know if someone has emphysema? Can you find examples in the Video?

Tadge Bredwell: emphysema (see Video Script pgs 45-46).
Richard Heath: emphysema (see Video Script pgs 45-46).