PROSTATE CANCER
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Descriptive Epidemiology
See chapter 7.14 in WCRF/AICR Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective.
680,000 new cases in 2002
Rare under age 50, increases almost exponentially after 50, and in particular after age 60-70
Incidence much more common in developed world – account for 75% of all new cases.
High risk areas: North America, Europe and Australia.
Substantial variations in incidence also within country. Highest incidence rates in the world in African-American men in the US, and lowest among men in China.
Rates in Africa are much lower than among African-American men in the US.
Rates increasing in recent years in many parts of the world...
Increase due to widespread screening? (No change in dietary or other exposures that could otherwise explain this increase)
NOTE: A large number of undiagnosed tumours are often found post mortem... Up to 40% by age 80!!
Survival – 60% alive after 5 years
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Pathogenesis
70% of adenocarcinoma arise in the peripheral zone, 25% in the transitional zone, and the rest in the central zone.
Spreads locally, direct invasion through the capsule into the seminal vesicles and the base of the bladder.
Bony metastases common.
Natural history highly variable and unpredictable – some metastasize before they give any local symptoms, and some remain undetected until death...
Multiple genetic events – initiation factors may be similar throughout the world, while rate of promotion or progression could vary.
Dietary risk factors
CONVINCING EVIDENCE - decreases risk:
- None
CONVINCING EVIDENCE - increases risk:
- None
PROBABLE EVIDENCE - decreases risk:
- Foods containing lycopene and selenium
- Selenium
PROBABLE EVIDENCE - increases risk:
- Diets high in calcium
LIMITED/SUGGESTIVE EVIDENCE - decreases risk:
Pulses
Foods containing vitamin E
Alpha-tocopherol
LIMITED/SUGGESTIVE EVIDENCE - increases risk:
Processed meat
Milk and dairy products
SUBSTANTIAL EFFECT ON RISK UNLIKELY:
- Beta-carotene
Most effective dietary means of preventing prostate cancer
NO convincing evidence
Possible:
- Diets high in vegetables and low in processed meat, milk and dairy products