Tamoxifen citrate has been approved for primary reduction of breast cancer risk since 1998, but studies suggest that its use for primary prevention is limited. The authors report on a national survey mailed to 350 primary care physicians regarding past prescription of tamoxifen, intention to prescribe tamoxifen in hypothetical scenarios, and potential predisposing and enabling factors. The survey focused on primary care physicians because most patients eligible for tamoxifen will not be seen in clinics for high-risk patients or oncology practices. A minority of primary care physicians (27.4%) reported having prescribed tamoxifen for breast cancer prevention at least once in the prior 12 months. This estimate is lower than might be expected based on the estimated proportion of women who would experience a net benefit from tamoxifen. Survey results show that physicians who had prescribed tamoxifen were older, less likely to be women and more likely to see more than 100 patients per week. They also were more likely to be in practice with five or fewer primary care physicians. Results also show that the decision to prescribe tamoxifen is affected by the ability to determine eligibility, personal experience with breast cancer as much as perceptions of the risks and benefits, and most notably patient demand. A woman's risk of endometrial cancer from tamoxifen seems to have less impact on prescribing decisions than the magnitude of her breast cancer risk.
The authors suggest that strategies to increase the uptake of chemoprevention in the future should educate patients and physicians about the availability of interventions, such as calculating tools for determining eligibility.