A 53-year-old postmenopausal woman comes to the office for a follow-up visit. The patient recently had surgery for early-stage, estrogen receptor-positive breast cancer diagnosed on screening mammography. She was started on an aromatase inhibitor postoperatively but discontinued the therapy due to intolerable side effects. Today she is starting tamoxifen as an adjuvant endocrine treatment. The patient has no other chronic medical problems. Her mother has type 2 diabetes mellitus and had a minor stroke. Her father died from metastatic colon cancer.
Vital signs are within normal limits. BMI is 29 kg/m².
This patient is at highest risk for which of the following complications from tamoxifen therapy?

Question

Quizplus · Accepted Answer

11ec193a_97de_5312_853d_9b9222a9e1b3_MD0002_00 Tamoxifen, a selective estrogen receptor modulator with mixed agonist/antagonist action, is used as adjuvant endocrine therapy in patients with nonmetastatic, estrogen receptor-positive breast cancer. Tamoxifen is considered first-line therapy in premenopausal women; it can also be used in postmenopausal women who have intolerable side effects (eg, joint pain) from, or contraindications to, aromatase inhibitors. Tamoxifen is associated with a 2- to 3-fold increased rate of venous thromboembolic events, particularly in the first 2 years of use. Therefore, women on tamoxifen are advised to discontinue it several days prior to activities that further increase the risk of venous thromboembolism (eg, surgery, travel). (Choice A) Tamoxifen is not associated with the development of diabetes mellitus. (Choice B) Tamoxifen does not adversely affect the risk for coronary artery disease in women with or without pre-existing disease. (Choice C) In premenopausal women, tamoxifen decreases bone mineral density (likely due to its partial antagonist activity). In contrast, in postmenopausal women, tamoxifen increases bone density (likely due to its partial agonist activity) and decreases the risk of osteoporotic fracture. However, tamoxifen is not recommended for osteoporosis prevention due to its association with endometrial cancer. (Choice D) Limited data suggest that tamoxifen may reduce the risk of ovarian cancer and may be used in patients with recurrent or advanced-stage ovarian cancer. Tamoxifen does increase the risk of uterine cancers (endometrial and uterine sarcoma) in postmenopausal women. Current recommendations include annual examinations. Further screening, such as ultrasound or endometrial biopsy in asymptomatic women, has not been proven beneficial and is not recommended. However, women with symptoms suggesting cancer (eg, abnormal or postmenopausal bleeding) require evaluation with an ultrasound and biopsy. Educational objective: Tamoxifen, an estrogen antagonist in the breast, is used for adjuvant therapy in some patients with estrogen receptor-positive breast cancer. Tamoxifen is associated with an increased risk for venous thromboembolism. __________ References: Clustering of venous thrombosis events at the start of tamoxifen therapy in breast cancer: a population-based experience. (http://www.ncbi.nlm.nih.gov/pubmed/22154240) Stopping tamoxifen peri-operatively for VTE risk reduction: a proposed management algorithm. (http://www.ncbi.nlm.nih.gov/pubmed/22609485)

A 53-Year-Old Postmenopausal Woman Comes to the Office for a Follow-Up