American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the recommended duration for tamoxifen therapy in premenopausal breast cancer patients?

1. At least 3 years

2. At least 5 years

3. At least 7 years

4. At least 10 years

The correct answer is: At least 5 years

The recommended duration for tamoxifen therapy in premenopausal breast cancer patients is at least 5 years. This guideline is based on extensive research and clinical trials that have demonstrated the efficacy of tamoxifen in reducing the risk of breast cancer recurrence and improving overall survival rates in women with hormone receptor-positive breast cancer. Tamoxifen acts as a selective estrogen receptor modulator, which blocks estrogen's effects on breast tissue. A duration of 5 years of tamoxifen treatment has been shown to provide optimal therapeutic benefit, balancing the prevention of recurrence with manageable side effects. Important studies, such as the NSABP P-1 and ATAC trials, have contributed to this recommendation by demonstrating significant improvements in outcomes with 5 years of therapy. Extending the duration of tamoxifen therapy beyond 5 years may be considered in certain circumstances and guided by individual patient factors, but the standard remains at least 5 years for the majority of premenopausal patients. Therefore, this duration is supported by current clinical guidelines and evidence, making it the correct answer.