Give us clear, not convoluted, clinical practice guidelines

We regret that Michael Lawrence has been left confused and at a loss as to how to proceed. He feels that, because the Gail index has not been validated as a routine screening instrument, there are insufficient grounds for publication of the guideline in CMAJ.

The 2 committees that developed the guideline1 felt that there is high-quality evidence from a large North American randomized trial on the potential benefit of tamoxifen for prevention of breast cancer that cannot be ignored. The Gail index was used to define entry for this trial. However, the committees felt that it was premature for family physicians to routinely apply the Gail index to all women in their practices. Although the Gail index has not been validated for routine screening, it is widely used in certain settings and is here to stay. The Gail index is familiar to oncologists specializing in breast cancer and is being used to identify women for participation in ongoing clinical trials.

The issue of the use of tamoxifen to prevent breast cancer in women is certainly topical and one that many women wonder about, particularly if they have a family member with breast cancer. The use of tamoxifen to prevent breast cancer is in evolution as we await the results of additional clinical trials. We feel, however, that the guideline published in CMAJ on the chemoprevention of breast cancer equips a family physician with an approach to use if a patient asks about the use of tamoxifen to prevent breast cancer. The guideline gives a critical review of the evidence on the subject and presents the current state of the art. It tells a physician how to locate and use the Gail risk index. Finally, it also recommends that if a woman wants to pursue the issue further, there are now specialized centres across Canada that can provide counselling.

John Sehmer wants a concise recommendation concerning the use of tamoxifen to prevent breast cancer. There are many situations in medicine that are not clear-cut and involve trade-offs between efficacy and side effects. In addition, patients will attach their own values to these outcomes. This guideline was developed by a multidisciplinary group of practising clinicians and breast cancer survivors. There is also a lay version of this guideline. We hope that if one of Sehmer's patients approaches him about the use of tamoxifen to prevent breast cancer or asks about the Gail index, he will have a change of heart and find that the guideline is an excellent resource.