A 45-year-old female presents to your office with a 3-month hx of breast lump. She noticed this 3 months ago but did not come in because she thought it would go away. She denies pain, weight loss, nipple discharge or menstrual changes. Her last mammogram was 3 years ago. She has no significant medical history. She is on no medication and her general PE is negative.
On exam, she has a hard fixed 2 cm mass in the upper outer quadrant of her left breast with several palpable lymph nodes in her left axillary area. A breast biopsy confirms ductal breast carcinoma.
Further workup does not reveal distant metastasis. She undergoes lumpectomy and sentinel node biopsy. Pathology shows receptor estrogen-progesterone positive, and she has microscopic metastasis in the axillary lymph nodes. She is started on Tamoxifen.
What is the mechanism of action of this drug?
What are the adverse effects of this drug?
What is the length of treatment and why?
If this 45-year-old female is African American, what other drugs would you try? Be specific and provide a rationale for your answer.
