title: Colorectal cancer and oestrogen replacement therapy. A meta-analysis of epidemiological studies.
abstract: OBJECTIVE
  To determine if non-contraceptive oestrogen replacement therapy alters the risk of colorectal cancer.
  
  
  METHODS
  A search was made of the MEDLINE database (January 1974 to October 1993) and Current Contents (October-December 1993) and of reference lists of articles identified in the search. Sixteen studies were identified and fourteen met defined criteria for analysis.
  
  
  RESULTS
  The overall relative risk of oestrogen replacement therapy use and colorectal cancer was 0.92 (95% confidence interval, 0.74-1.15), which was not significantly different from unity (P > 0.05). The separate overall relative risks of oestrogen replacement therapy use for colon or rectal cancer were also not significantly different from unity.
  
  
  CONCLUSIONS
  When the results of all studies published to date are combined, there is no association between oestrogen replacement therapy and the incidence of colorectal cancer. However, long term randomised control trials are required to confirm this.
authors.affiliation: Department of Obstetrics and Gynaecology, University of Adelaide, SA.
authors.forename: S C
authors.initials: SC
authors.lastname: MacLennan
authors.forename: A H
authors.initials: AH
authors.lastname: MacLennan
authors.forename: P
authors.initials: P
authors.lastname: Ryan
mesh_terms: D015179:Colorectal Neoplasms / Q000139:chemically induced* / Q000453:epidemiology; D016001:Confidence Intervals; D015914:Estrogen Replacement Therapy / Q000009:adverse effects*; D005260:Female; D006801:Humans; D012307:Risk Factors