Background: Although tamoxifen citrate has been approved for primary reduction of breast cancer risk since 1998, little is known about the prescription of tamoxifen by primary care physicians.
Methods: To investigate the determinants of prescription of tamoxifen for breast cancer prevention by primary care physicians, we mailed a national survey to 350 primary care physicians, including specialties of family practice, obstetrics and gynecology, and general internal medicine, regarding past prescription of tamoxifen, intention to prescribe tamoxifen in hypothetical scenarios, and potential predisposing and enabling factors.
Results: Ninety-six physicians (27.4%) reported having prescribed tamoxifen for breast cancer prevention at least once in the prior 12 months. After multivariate adjustment, having prescribed tamoxifen was associated with the physician having a family member with breast cancer (odds ratio [OR], 2.66; 95% confidence interval [CI], 1.21-5.85), patients who asked for information about tamoxifen (OR, 3.98; 95% CI, 1.44-11.04), and the beliefs that the benefits of tamoxifen outweighed the risks (OR, 1.86; 95% CI, 1.07-3.24) and that eligibility was easy to determine (OR, 2.67; 95% CI, 1.35-5.29). In hypothetical scenarios, the prescription of tamoxifen was affected by the patient's family history of breast cancer but not by her risk for endometrial cancer (ie, hysterectomy status).
Conclusions: A minority of primary care physicians have prescribed tamoxifen for breast cancer prevention. The decision to prescribe tamoxifen is affected by the ability to determine eligibility, patient demand, and personal experience with breast cancer as much as perceptions of the risks and benefits. 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.