Text Description: Figure A-1. Analytic Framework: Chemoprevention of Breast Cancer

The analytic framework begins on the left side with the population at risk. Several different populations should be considered:

1. Premenopausal women with "average" risk of breast cancer.
2. Premenopausal women with "high" risk of breast cancer.
3. Postmenopausal women with "average" risk of breast cancer.
4. Postmenopausal women with "high" risk of breast cancer.

In addition, because of the effect of tamoxifen or other chemopreventive agents on potentially serious conditions other than breast cancer, women with particularly increased (or decreased) risk of thromboembolic events, bone fractures, or endometrial cancer should be considered separately.

Moving to the right in the analytic framework, the "chemoprevention" arrow points to a box labeled "incidence of breast cancer." Moving downward from the chemoprevention arrow is an "adverse effects/costs" arrow. Some of the adverse effects of tamoxifen or raloxifene are deep vein thromboembolism, pulmonary embolism, stroke, endometrial cancer, hot flashes, and cataracts.

Possible benefits from tamoxifen or raloxifene chemoprevention include reduced risk of heart disease and bone fractures. These are listed together in a separate box: "other beneficial effects."

Farther to the right is a "treatment" arrow, leading to a box labeled "health outcomes," which includes mortality and/or morbidity from breast cancer. We also consider "incidence of breast cancer" to be a health outcome worthy of consideration in its own right.

Leading downward from the "treatment" arrow is another "adverse effects/costs" arrow. Included here are adverse effects from chemotherapy, surgery, and radiation therapy used to treat breast cancer.

Finally, an "overarching" arrow for chemoprevention leads directly to reduced mortality and morbidity from breast cancer.

Key Questions

The primary, overarching question, shown as the topmost line in the figure, is the following:

1. Do chemopreventive agents reduce mortality from breast cancer?

The secondary questions (i.e., linkage questions), shown in the body of the figure, are the following:

2. Do chemopreventive agents reduce the incidence of breast cancer?
3. Do chemopreventive agents have other beneficial effects?
4. Do chemopreventive agents increase the risk of adverse effects?
5. What are the costs associated with chemoprevention of breast cancer?

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