Decline in breast cancer since HRT study
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* Wayne Kondro

*   © 2007 Canadian Medical Association or its licensors

Although the causal link hasn't been conclusively established, US researchers say there's been a remarkable decline in breast cancer rates since fewer women began taking hormone replacement therapy (HRT) to alleviate the symptoms of menopause.

The overall incidence of breast cancer in the US declined 7% between 2002 and 2003, while the number of women aged 50–69 diagnosed with estrogen receptor positive (ER-positive) breast cancer declined 12% over the same period, when millions of women stopped taking HRT after the release of a July 2002 Women's Health Initiative study indicating HRT bore more risks than benefits.

Some 14 000 fewer women were diagnosed with breast cancer in 2003 than in 2002, when an estimated 203 500 cases were diagnosed, researchers at the University of Texas MC Anderson Cancer Center told the 29th annual San Antonio Breast Cancer Symposium last month.

Senior investigator and MC Anderson Professor Dr. Donald Berry stated that the findings suggest the magnitude of the RT effect may be “much greater than originally thought.” But colleague Dr. Peter Ravdin cautioned the link can only be “indirectly” inferred.

The investigators also indicated it's unclear whether the decline will continue or whether women have merely delayed diagnosis by slowing the growth of tumours that fall under mammography's radar.

In other findings presented at the symposium, Canadian researchers Dr. Margot Burnell and Dr. Mark Levine said a clinical trial of 3 commonly used chemotherapy regimes indicates CEF (a combination of cyclophosphamide, epirubicin and fluorouracil) is more effective at preventing breast cancer recurrence than the widely used AC/T (doxorubicin and cyclophosphamide followed by paclitaxel) or the more rarely used new regime EC/T (epirubicin and cylcophosphamide, followed by paclitaxel).

The trial, which tracked (for 30 months) 2104 North American women aged under 60 who had been diagnosed with lymph-node-positive or high-risk node-negative breast cancer and who'd undergone surgery, found the 3-year recurrence-free survival rate for CET was 90.1%, as compared to 89.5% for EC/T and 85% for AC/T.

The investigators stressed those variable rates must be weighed against potential side effects. AC/T users can suffer from neurological effects (commonly called “chemo brain”), and women on CEF and EC/T have a higher incidence of heart and blood problems.