September 7, 2010, 11:09 pm
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the prostate

CZ=central zone; PZ=peripheral zone; TZ=transitional zone. Adapted from Robbins Pathologic Basis of Disease 1999.3

  • The anatomy of the prostate has been a controversial subject for many years. 1
  • Three zones: peripheral, transition and central.1, 2
  • Peripheral zone = 65% of normal prostate volume.1
  • Central zone = 25% prostatic volume.1
  • Transition zone = 5-10% of the prostate in young adults.1
  • Anatomical boundaries are subtle; histological distinctions are difficult to perceive.1
  • These zones give rise to various pathologies.
  • Nodules of benign prostatic tissue usually originate from the transition zone.1
  • Most prostate cancers (70%) arise in the peripheral zone.1
  • Peripheral carcinomas can be palpated during Digital Rectal Examination (DRE).
  • About 5-15% of cancers arise in the central zone; the remainder in the transition zone.4

References

  1. Kirby RS, Christmas TJ and Brawer MK. Prostate Cancer 2nd edition. Mosby International Limited, London 2001.
  2. McNeal JE. Regional morphology and pathology of the prostate. Am J Clin Pathol 1968; 49: 347-357.
  3. Cotran RS, Kumar V, Collins T (eds). Robbins Pathologic Basis of Disease, 6th ed. Philadelphia, WB Saunders 1999: 1025.
  4. Kirby RS, Brawer MK, Denis LJ. Fast facts: prostate cancer (2nd edition). Health Press, Oxford, UK 1998

Facts and figures

  • Prostate cancer is the most common registrable cancer in Australian men.1
  • About 10,500 Australian men are diagnosed with prostate cancer each year.1
  • More than 2,600 Australian men die of prostate cancer each year.1
  • One in 11 Australian men will develop prostate cancer by the age of 75.1

References

  1. 1. The Cancer Council NSW. Fact Sheet – Prostate Cancer, July 2004. Online. Viewed 3/12/04. Available at http://www.cancercouncil.com.au/editorial.asp?pageid=1121

Prostate cancer incidence and mortality1

incidence

Source: The Cancer Council NSW 2004.1

References

  1. The Cancer Council NSW, June 2004. Online. Accessed on 16/12/04. Available at http://www.cancercouncil.com.au/editorial.asp?pageID=302

 


Risk factors and risk reduction

  • Age is the strongest risk factor for prostate cancer.1

Family history

  • Single first degree relative (father or brother) with prostate cancer: three-fold increased risk.2
family history
  • Three first degree relatives: 11-fold increased risk.4

Hormones

  • Testosterone and its metabolite dihydrotestosterone (DHT): vital for normal prostate growth and may play a role in prostate cancer development.4
  • Prostate cancer almost never develops in men castrated before puberty.4

Occupational factors

  • Men exposed to cadmium and men working in the nuclear power industry may have an increased risk of prostate cancer.1

Vasectomy

  • Vasectomy has been proposed as a risk factor for prostate cancer.1
  • However, recent studies have suggested that there is probably no causal link.5,6

Sexual behaviour

  • Controversial issue.
  • Past data suggest prostate cancer risk is increased in men who became sexually active when young, or
  • have multiple partners and a history of sexually transmitted disease.7
  • Conflicting data show:
    • an increase in prostate cancer in men with low levels of sexual activity8
    • prostate cancer mortality in celibate priests was comparable to that of the general population8
    • frequency of ejaculation may actually reduce overall prostate cancer risk.9
diet

References

  1. Kirby RS, Brawer MK, Denis LJ. Fast facts: prostate cancer (2nd edition). Health Press, Oxford, UK 1998.
  2. Woolf CM. An investigation of the familial aspects of carcinoma of the prostate. Cancer 1960; 13:739-743.
  3. Carter BS et al. Hereditary prostate cancer: epidemiologic and clinical features. J Urol. 1993 Sep;150(3):797-802.
  4. Steinberg GS et al. Family history and the risk of prostate cancer. Prostate 1990;17:337-340.
  5. Dennis LK et al. Vasectomy and the risk of prostate cancer: a meta-analysis examining vasectomy status, age at vasectomy, and time since vasectomy. Prostate Cancer Prostatic Dis 2002; 5: 193-203.
  6. Lynge E. Prostate cancer is not increased in men with vasectomy in Denmark. J Urol 2002; 168: 488-490.
  7. Steele R et al. Sexual factors in the epidemiology of cancer of the prostate. J Chron Dis 1971; 24: 29-37.
  8. Ross RK et al. A cohort study of mortality from cancer of the prostate in Catholic priests. British Journal of Cancer 1981; 43: 223-235.
  9. Leitzmann MF et al. Ejaculation frequency and subsequent risk of prostate cancer. JAMA 2004; 291: 1578-1586.
  10. Giovannucci E et al. A prospective study of dietary fat and risk of prostate cancer. J Natl Cancer Inst 1993; 85: 1571-1579.
  11. Klein EA. Selenium: epidemiology and basic science. J Urol 2004 Feb;171(2 Pt 2):S50-53.
  12. Clark LC et al. Decreased incidence of prostate cancer with selenium supplementation: results of a double-blind cancer prevention trial. Br J Urol 1998; 81: 730-734.
  13. ann PH et al. Lower prostate cancer risk in men with elevated plasma lycopene levels: results of a prospective analysis. Cancer Res 1999; 59: 1225-1230.
  14. einonen OP et al. Prostate cancer and supplementation with alpha-tocopherol and beta-carotene: incidence and mortality in a controlled trial. J Natl Cancer Inst 1998; 90: 440-446.
  15. Lee MM et al. Soy and isoflavone consumption in relation to prostate cancer risk in China. Cancer Epidemiol Biomarkers Prev 2003; Jul;12(7):665-668.

 

Risk: issues and implications

  • The lifetime risk of developing microscopic or latent prostate cancer is about 30%.1
  • Lifetime risk of developing breast cancer is about 9.2%.2
  • Lifetime risk of prostate cancer becoming apparent or causing problems is only about 10%.1
  • For many older men, prostate cancer may be present but never cause problems and men will die with their prostate cancer rather than of their prostate cancer.1
  • Lifetime risk of dying from cancer
    Prostate = 2-3%.1
    Breast cancer = 2.2%.2
  • Incidence rates and mortality rates increase with age, however, 66% of new cases and 32% of deaths occurred in males less than 75 years old.3

References

  1. Urological Society of Australasia. Consumer information: what is the prostate and what is prostate cancer? Online. Viewed 3/12/04. Available at: http://www.urosoc.org.au/info/ainfo.html.
  2. Coates M, Armstrong B. Cancer in New South Wales. Incidence and mortality 1994. Sydney, NSW Cancer Council, 1997.
  3. The Cancer Council NSW. Fact Sheet – Prostate Cancer, July 2004. Online. Viewed 3/12/04. Available at http://www.cancercouncil.com.au/editorial.asp?pageid=1121
 

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