A recent study in Australia confirms that hormone replacement therapy (HRT) affects the accuracy of mammographic screening (The Lancet-January 22, 2000). I have been aware of this phenomenon for over twenty years but have been unable to interest anyone in conducting such a study. Since HRT affects the accuracy of mammograms it is logical to conclude that it also may affect the accuracy of the physical exam in detecting breast cancer. A study is needed to determine if HRT also makes breast cancer undetectable because no mass may be palpable. I call this effect of HRT on breast cancer "masking".

Many women with breast cancer who are on HRT may be unaware of the cancer because no mass is present and the mammogram is negative. A study of a sizable number of women on HRT, say ten thousand, is needed. Each woman would have a baseline breast examination as well as a mammogram. The HRT would then be discontinued for two to four weeks. Each woman would then receive another breast examination and mammogram. Any difference in breast findings after the HRT was stopped must result in a biopsy. The difference may be as subtle as a slight thickening of the tissue noted on palpation, or it may be obvious, such as an visible induration involving a large part of the breast. It may also be bilateral as in the first case that I observed over thirty years ago. (see case histories). If the breast exam and mammogram remain negative after the two to four weeks off of the HRT, the hormone regimen would be resumed.

I would recommend that the study also include women on hormone therapy for birth control, or other reasons, as well. The personal case histories I have cited have included pre-menopausal women on hormonal birth control.

While the Australian study results provide compelling evidence that HRT has an effect on breast cancer detection by means of mammography, much more research is needed. I sincerely hope that further research projects as generally outlined above will be forthcoming.