Risk Factors of Prostate Cancer

While information on risk factors for prostate  cancer  is accumulating rapidly, there remains a high level  of uncertainty over the epidemiology of prostate  cancer. Unlike other cancers such as bowel and breast there is a lack of strong epidemiological associations with identifiable risk factors. Hence there is limited  capacity to target definite  sub-groups in the population for early  detection efforts.

Primary  risk factors  for prostate  cancer  have  been  reviewed in the 1996 AHTAC Report on Prostate  Cancer  Screening (AHTAC, 1996)  and  the more  recent  update of this report  (Weller et al, 1999).  To briefly  summarise this material:

 

Geographic and  racial differences

  • both genetic and exogenous factors are likely to play  a role
  • incidence varies  substantially in countries around the world—although this may  be due  to differences in case ascertainment in the different  countries
  • reported age-standardised incidence in Black  Americans exceeds that in

Japanese men by a factor of around 50 (Garraway & Alexander, 1997)

  • the high variability in incidence cannot  be explained by genetic factors.

Diet

  • population studies  shows  high correlations between prostate  cancer  deaths and total fat consumption (Pienta  et al, 1996)
  • Giovannucci et al (1993)  found,  in the Health Professionals Follow-up Study, that intake  of animal fat was  associated with an increased risk of prostate cancer. Fat from fish, vegetable and dairy  sources (except butter)  was  not found  to be related to risk for prostate  cancer.

Genetic  and  familial factors

  • several studies  demonstrate a higher  incidence of prostate  cancer  among  the relatives of men with prostate  cancer  than among  the relatives of control groups  (Pienta  et al, 1996),  usually of the order of a two-fold  increase in risk for male first-degree relatives (Walsh  and Partin, 1997)
  • a recent  systematic review of the hereditary aspects of prostate  cancer concluded that, for first-degree relatives of men with prostate  cancer, the relative risk ranges  from 1.7 to 8.7; greater  numbers of affected family members and early onset among  family  members are the most significant predictors of risk (McLellan  & Norman,  1995).

 

Carter et al (1993)  constructed the following table  on family  history  and risk of prostate  cancer:

       Table 1: Family  history  and risk  of prostate  cancer

Age at onset (years) Additional  affected relatives Relative  risk

70

None

1.0

60

None

1.5

50

None

2.0

70

1 or more

4.0

60

1 or more

5.0

50

1 or more

7.0

Other  factors

Selenium has been  observed to have  a protective effect for prostate  cancer; like many  other dietary components, this requires further verification in large, well- controlled trials (Clark  et al, 1998).

The role of phyto-oestrogens in prostate  cancer  has attracted considerable interest in recent  years  (Adlercreutz & Mazur,  1997; Hempstock et al,  1998).  The western diet is relatively deficient in these  substances compared with societies where large amounts of plant  foods and legumes are eaten. At present  there  are no definite recommendations about  the dietary amounts needed for
prevention of disease.

Source:

Clinical Practice Guidelines: Evidence-based information and recommendations for  the management of localised prostate cancer, A report  of the Australian Cancer  Network  Working Party on Management of Localised  Prostate Cancer, NHMRC, Oct 2002

References:

Adlercreutz H, Mazur W. Phyto-oestrogens and Western  diseases. Ann Med 1997 Apr;29(2):95–120

Carter BS, Bova  GS, Beaty  TH, et al. Hereditary prostate  cancer: epidemiologic and clinical features. The Journal  of Urology. 1993; 150:797–802

Clark LC, Dalkin  B, Krongrad  A, et al. Decreased incidence of prostate  cancer  with selenium supplementation: results  of a double-blind cancer  prevention trial. Br J Urol.  1998;  81:730–4

Garraway W M and Alexander F E. Prostate disease: epidemiology, natural  history and demographic shifts. Br J Urol. 1997; 79(suppl 2):3–8

Giovannucci E, Rimm E B, Colditz G A, Stampfer  M J, Ascherio  A, Chute C C and Willett  W C. A prospective study  of dietary fat and risk of prostate  cancer [see  comments]. J Natl Cancer  Inst. 1993 Oct 6, 85(19):1571–9; ISSN: 0027-8874

Hempstock J, Kavanagh JP and George  NJ. Growth inhibition of prostate  cell lines in vitro by phtyo-oestrogens. Br J Urol 1998 Oct;82(4):560–3

McLellan  D L and Norman R W. Hereditary aspects of prostate  cancer  [see comments]. CMAJ. 1995 Oct 1; 153(7):895–900; ISSN: 0820-3946

Pienta  KJ, Goodson  JA and Esper PS. Epidemiology of prostate  cancer: molecular and environmental clues.  Urology. 1996 Nov; 48(5):676–83; ISSN: 0090-4295

Walsh PC and Partin AW. Family history  facilitates the early  diagnosis of prostate carcinoma. Cancer.  1997;  80(9):1871–74

Weller  DP, Pinnock  C, Alderman  C, Moss J and Doust J. Screening for prostate cancer—update of the 1996 AHTAC report. Flinders  University of SA: Jan 1999

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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