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LUNG CANCER

http://meddev.uio.no/elaring/lcms13/ernaeringslaere/nutr-cancer-epidemiology/illustrations/lungs.jpg

See chapter 7.4 page 253 in WCRF/AICR Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective.

pdf Cancers

Descriptive epidemiology

Most common incident cancer. Around 1.4 million new cases in 2002.

Most common cause of cancer mortality.

Incidence and mortality in general increasing, mainly as a cause of increased smoking.

Rates increasing rapidly throughout the world, including in Asia, Latin American and Africa.

Even where smoking rates have declined is lung cancer still a major form of cancer.

Discussion question:
Why is lung cancer still high where smoking rates have declined?

Rates are highest in North American and Europe, and lowest in Africa (and South America).

Rates are much higher in men than in women – 75% occur in men.

The overwhelming cause of lung cancer is use of tobacco.

Smokers have 20-30 times increased risk of lung cancer compared to non-smokers.

Passive smoking may increase risk of lung cancer with 30-50%.

Survival rates are low – 7-12% of patients are alive after 5 years.

The most common forms of lung cancer are squamous cell cancer or small-cell carcinoma and adenocarcinoma

http://meddev.uio.no/elaring/lcms13/ernaeringslaere/nutr-cancer-epidemiology/illustrations/incidence_2008_lung.jpg

Pathogenesis:

  • Compounds in tobacco smoke (or in the air in the workplace) cause DNA damage across the genome. Failure to repair this damage in a crucial tumour suppressor gene or oncogenes can result in an expanding clone or abnormal cells.
  • Note: only 15% of smokers develop lung cancer ....
  • Variability in protective capacity of the lungs?

Non-dietary causes of lung cancer

  • Tobacco smoke (overwhelming cause)
  • Asbestos exposure
  • Certain occupational exposures (nickel, radon, chromium)

Dietary risk factors for lung cancer

CONVINCING EVIDENCE - decreases risk:

  • None

CONVINCING EVIDENCE - increases risk:

  • Arsenic in drinking water
  • Beta-carotene supplements


PROBABLE EVIDENCE - decreases risk:

  • Fruits
  • Foods containing carotenoids

PROBABLE EVIDENCE - increases risk:

  • None


LIMITED/SUGGESTIVE EVIDENCE - decreases risk:
Vegetables
Foods containing selenium and quercetin
Selenium

LIMITED/SUGGESTIVE EVIDENCE - increases risk:
Red and processed meat
Total fat
Butter
Retinol supplements
Low body fatness

Most effective ways of preventing lung cancer:

  • NOT to use tobacco

Most effective dietary means of preventing:

  • Consumption of diets high in fruits and vegetables

pdf Cancer Epidemiology