First IBIS results show tamoxifen reduces breast cancer in healthy high-...( First results from the long-awaited IBI...),Health

These preliminary results were presented at the 3rd European Breast Cancer Conference in Barcelona on Wednesday together with an overview of the four breast cancer prevention trials . Results from the previous studies have been mixed.

In addition, nine trials using tamoxifen for treatment of breast cancer patients and who were therefore at high risk of developing a second cancer in the opposite breast, were also reviewed. IBIS lead investigator Professor Jack Cuzick, who is from Cancer Research UK, told the conference that the incidence of breast cancer was reduced by a third in the women taking tamoxifen in the IBIS trial with 68 cases of breast cancer compared with 101 among those taking the placebo. When the results of all the prevention trials were combined the overall reduction was 38%. The trials of the adjuvant treatment of breast cancer in patients showed a slightly greater (46%) reduction in the incidence of second cancers in the opposite breast.

The reduction in incidence of breast cancer in IBIS was found only in oestrogen receptor positive (hormone positive) breast cancers with no effect on cancers that were oestrogen receptor negative. The benefit was the same whatever the age of the woman, whatever the level of risk and whether or not she was taking hormone replacement therapy.

However, while the benefits of tamoxifen for treating breast cancer patients are indisputable, there is still no conclusive answer as to whether the benefits outweigh the side effects for prevention in healthy women, according to Professor Cuzick. "All along the line, we have kept the volunteers in the trial fully informed of developments. That is why we and the Independent Data Monitoring Committee felt it was right to report thes
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Contact: Margaret Willson
m.willson@mwcommunications.org.uk
34-93-3644487
Federation of European Cancer Societies
20-Mar-2002