COLORECTAL-CANCER AND ESTROGEN REPLACEMENT THERAPY - A METAANALYSIS OF EPIDEMIOLOGIC STUDIES

Objective: To determine if non-contraceptive oestrogen replacement the rapy alters the risk of colorectal cancer. Data sources: A search was made of the MEDLINE database (January 1974 to October 1993) and Curren t 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. Data synthesis: The overall relati ve risk of oestrogen replacement therapy use and colorectal cancer was 0.92 (95% confidence interval, 0.74-1.15), which was not significantl y 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. Conclusion: When the resu lts of all studies published to date are combined, there is no associa tion between oestrogen replacement therapy and the incidence of colore ctal cancer. However, long term randomised control trials are required to confirm this.