Switching from nonsteroidal aromatase inhibitors to exemestane and its impact on menopausal symptoms.

Abstract

e13098 Background: Aromatase inhibitors (AIs) are the most used adjuvant treatment in post-menopausal women with favorable oncotype, hormone receptor-positive (HR+) early breast cancer. Nonsteroidal AIs, such as anastrozole and letrozole, are associated with menopausal side effects including arthralgias, vaginal dryness, and hot flashes. Steroidal AIs, such as exemestane, however, have mild androgenic activity, thus minimizing the risk for these side effects. While studies show exemestane exhibits less bone toxicity compared to anastrozole, there has not yet been a proven significant difference in all menopausal symptoms. Nevertheless, switching from nonsteroidal to steroidal AI is still commonly seen in clinical practice. In this study, we aimed to examine the impact of switching from nonsteroidal to steroidal AI on menopausal side effects. Methods: We performed a retrospective review of patients diagnosed with HR+ breast cancer managed at an urban academic center from 2010-2023. Patients initially treated with anastrozole or letrozole and switched to exemestane were identified. Pathology records, treatment plans, and documented side effects were abstracted from medical records, as were baseline demographics. Symptoms were graded based on severity before and after each hormone therapy: mild grade described intermittent symptoms that did not require intervention; moderate grade described persistent daily symptoms or those that improved with additional intervention; severe grade described persistent disabling symptoms that required change in hormone therapy. Wilcoxon signed-rank tests were used to compare severity of menopausal symptoms before and after switching to exemestane. Results: There were 128 patients included in the study. Median age at diagnosis was 62.5 years; 13% pre-menopausal, 80% post-menopausal, 4% perimenopausal, and 3% unknown. Most patients were diagnosed with invasive ductal carcinoma (80%) and 45% were found to have stage IA breast cancer. The median amount of time on first and second lines of endocrine therapy were 11 and 25 months, respectively. Ninety-six patients (75%) reported menopausal symptoms on nonsteroidal AI, and 66% subsequently switched to exemestane due to severity of these symptoms. The most reported symptoms were arthralgias (79%), hot flashes (27%), body aches (25%), fatigue (10%), and vaginal dryness (9%). Of those with menopausal symptoms, 51% noted a decrease in symptom severity after switching to exemestane: 4 improved from moderate to mild, 21 from severe to moderate, and 24 from severe to mild. This decrease in severity was statistically significant across all menopausal symptoms (p<0.001). Conclusions: HR+ breast cancer patients exhibited a significant decrease in all menopausal symptoms when switching from nonsteroidal to steroidal AI. Further research is needed to examine the impact of this switch on a wider range of symptoms.