The oncology team proposes a trial of leuprolide, a gonadotropin-releasing hormone agonist that downregulates pituitary receptors, subsequently suppressing female reproductive hormones, which in turn stops the ovaries from producing estrogen so there is a minimal amount of estrogen to promote the growth of estrogen–receptor-positive breast cancer. Mrs. L declines this agent because she is concerned that she will gain weight. Instead, Mrs. L expresses interest in undergoing an oophorectomy to reduce her estrogen level. In the meantime, based on her reproductive hormone levels (FSH and estradiol levels) which are indicative of postmenopausal status, the oncology team prescribes the aromatase inhibitor (AI) exemestane 25 mg/d. The AI helps to decrease the amount of estrogen the body makes peripherally, which is the main source of estrogen in postmenopausal women.
The authors’ observations
Estrogen originates in the ovaries in premenopausal women; it is also produced by peripheral conversion of androgens to estrogen in adipose tissues and muscle in postmenopausal women.19 Aromatase inhibitors block the enzyme aromatase that converts androgen to estrogen, which leads to estrogen deficiency in postmenopausal women and possibly to neuropsychiatric effects.19
The results of studies assessing the adverse psychiatric effects of AIs are mixed. When the results of studies evaluating tamoxifen are compared with those evaluating AIs, overall patients who received AIs had less severe or less frequent mood symptoms. One possible explanation could be that AIs are relatively new compared with tamoxifen. Second, AIs are more commonly used in postmenopausal women with breast cancer, and these patients’ overall estrogen level is significantly lower than that of premenopausal women with breast cancer. Therefore, the degree of hormone fluctuation is less intense in postmenopausal breast cancer survivors.
OUTCOME
After starting exemestane, and while still receiving venlafaxine, Mrs. L no longer experiences severe depressive symptoms. After 8 months, venlafaxine is discontinued. She continues to deny depressive symptoms but has intermittent anxiety, which she is able to manage without psychiatric medication. She continues to remain adherent with ongoing exemestane treatment, with no evidence of disease progression or recurrence.
The authors’ observations
For patients with estrogen-positive breast cancer, the decision to discontinue tamoxifen because of unacceptable adverse effects is an important one because it may increase the risk of cancer recurrence. Psychiatrists have an important role in supporting the patient through this process, helping patients understand alternatives, and working with the oncology team to formulate a plan that is acceptable to everyone.
Continue to: Bottom Line