Influence of HRT on prognostic factors for breast cancer: a systematic review after the Women's Health Initiative trial.
BACKGROUND
Mortality due to breast cancer has been reported to be the same or even lower in HRT users than in non-users. This has been attributed to earlier diagnosis and to better prognosis. Nevertheless, more advanced disease in HRT users was reported recently by the Women's Health Initiative (WHI) study. The objective of this study was to assess, using a systematic review of current literature, whether the data of the WHI study are in contradiction to observational data.


METHODS
We selected 25 studies, for which we evaluated the methodology, the characteristics of the studied populations, confounding breast cancer risk factors and prognostic indicators.


RESULTS
The WHI study, showing a worsening of some prognostic parameters, is in contradiction to most published observational studies. Most observational studies are retrospective, not well matched and did not consider most confounding factors. Their methodology and selection criteria varied considerably and the number of patients was often small. No differences in the distributions of histology, grade or steroid receptors were observed in the WHI trial, while this was the case in some of the observational studies. Other parameters (S phase, protein Neu, Bcl-2 gene, protein p53 and E-cadherin, cathepsin D) were not reported in the WHI trial.


CONCLUSIONS
In view of these data, the current clinical message to patients should be changed: one can no longer declare that breast cancers developed while using HRT are of better prognosis.
Antoine
Caroline
C
Department of Obstetrics and Gynaecology, Free Universities of Brussels (VUB-ULB) CHU Saint-Pierre, Hoogstrasse 322, 1000 Brussels, Belgium.
Liebens
Fabienne
F
Carly
Birgit
B
Pastijn
Anne
A
Rozenberg
Serge
S
D000368:Aged; D001943:Breast Neoplasms / Q000139:chemically induced* / Q000401:mortality*; D015914:Estrogen Replacement Therapy / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008875:Middle Aged; D011379:Prognosis; D012307:Risk Factors; D014930:Women