A 65-year-old man comes to the office due to advanced prostate cancer with bone metastases. For the last 4 months, he has been treated with a GnRH agonist, which has significantly reduced his bone pain. However, the patient now reports discomfort at the anterior chest wall. Physical examination reveals bilateral, mildly tender enlargement of the breast tissue behind the nipple-areolar complex. Early initiation of which of the following medications would be most appropriate for preventing this patient's breast symptoms?

Question

A 65-year-old man comes to the office due to advanced prostate cancer with bone metastases.  For the last 4 months, he has been treated with a GnRH agonist, which has significantly reduced his bone pain.  However, the patient now reports discomfort at the anterior chest wall.  Physical examination reveals bilateral, mildly tender enlargement of the breast tissue behind the nipple-areolar complex.  Early initiation of which of the following medications would be most appropriate for preventing this patient's breast symptoms?

Quizplus · Accepted Answer

11ec160b_3bb8_06e9_9249_11ef568d1cce_MD0001_00 Gynecomastia is the development of glandular breast tissue in males. It is characterized by ductal epithelial hyperplasia with fibrosis of the surrounding stroma. Breast growth is inhibited by androgens and promoted by estrogens; conditions that increase the estrogen to androgen ratio can lead to gynecomastia. Common pathologic causes include cirrhosis (increased aromatase activity, decreased clearance of estrogens), end-stage renal disease (decreased testosterone production), and medications (eg, spironolactone, ketoconazole). Men with prostate cancer who receive androgen-deprivation therapy (eg, orchiectomy, long-acting GnRH agonists, androgen receptor inhibitors) can develop gynecomastia due to dramatic (>95%) reductions in circulating testosterone (with lesser reductions in estrogens). Treatment with tamoxifen, a selective estrogen receptor modulator that acts as an estrogen antagonist in the breast, can reduce the risk of gynecomastia in these patients. (Choice A) Bicalutamide is a testosterone receptor antagonist used in the treatment of prostate cancer. This drug can cause or worsen gynecomastia due to the reduced physiologic testosterone effect. (Choice B) Danazol is a synthetic steroid with androgenic and antiestrogenic effects. It may improve gynecomastia in patients with hypogonadism but can lead to rapid growth of prostate cancer and would not be appropriate for this patient. (Choices C and D) Finasteride is a 5-α reductase inhibitor that reduces the conversion of testosterone to dihydrotestosterone; it is used for treatment of benign prostatic hyperplasia and male-pattern hair loss. Spironolactone is an aldosterone antagonist that also decreases testosterone production and inhibits the testosterone receptor; it is commonly used for heart failure, cirrhosis, and hypertension. Both of these agents are associated with increased risk of gynecomastia. Educational objective: Gynecomastia is the development of glandular breast tissue in males and is commonly seen in men receiving androgen deprivation therapy for prostate cancer. Tamoxifen inhibits the effect of estrogen on breast tissue and can reduce the risk of gynecomastia in these patients.

A 65-Year-Old Man Comes to the Office Due to Advanced