Abstract P5-18-11: Impact of supportive therapies on tolerance of aromatase inhibitors in patients with early-stage, hormone-positive breast cancer

Abstract

Abstract Background: Aromatase inhibitors (AI) are standard of care in the treatment of early-stage hormone positive (HR+) breast cancer (BC). Commonly, these medications cause significant side effects which limit tolerability and often require a change in therapy. Supportive therapies are an essential part of treatment plans to improve adherence and quality of life. Studies in the last decade have demonstrated the critical role of supportive management in mitigating side effects from AI, such as the reduction in AI related joint pain with acupuncture or use of low dose oxybutynin for hot flashes. The aim of this study was to evaluate the real world use of supportive therapies for AI toxicities over the last decade and to determine if they were associated with patient adherence to initial AI treatment. Methods: We performed a retrospective chart review of all female patients at our academic institution with early-stage, HR+ BC who were initiated on adjuvant AI therapy between 2011-2020. From the electronic medical record, we collected information on patient demographics, AI side effects (hot flashes, vaginal dryness, joint pains, osteopenia/osteoporosis), use of supportive therapies, and duration of first AI therapy. Primary endpoint was the rate of discontinuation of AI at 1 year among those who used supportive therapies compared with those who did not. The Wilcoxon rank sum test, Fisher's exact test, Kruskal-Wallis rank sum test, and Pearson's Chi-squared test methods were used to compare rates of discontinuation of front-line AI therapy for each group. Results: We identified 990 patients (pts) with early-stage, HR+ BC who were started on adjuvant AI between 2011-2020. Of these patients, 97% (n= 963) had AI related side effects yet only 51% (n=504) received supportive therapies. The overall discontinuation rate within 1 year was 14.8% (147 of 990 pts). Patients who received at least 1 supportive therapy were more likely to remain on AI and had a lower 1 year discontinuation rate of 10% (51 of 504 pts) compared to 20% (96 of 486 pts) for those who did not receive any supportive therapy (p<0.001). The most commonly used supportive therapies were bone strengthening agents, with 35.6% (n=352) of patients receiving either denosumab or zoledronic acid, followed by acupuncture used in 11.2% (n=111) of patients. The use of acupuncture increased in 2018, compared to years prior (35 pts from 2011-2017, and 76 pts from 2018-2020). Similarly, oxybutynin use increased in 2019, compared to years prior (9 pts from 2011-2018, and 28 pts from 2019-2020). Upon further analysis, younger age was significantly associated with a higher 1 year discontinuation rate (median age 62 years in <1 year AI treatment group, and 64 years in >1 year AI treatment group, p=0.003). Race also appeared to have an impact on AI tolerance. Although only 31% (39 of 126 pts; p < 0.001) of Black patients received supportive therapy, this group had the lowest 1 year discontinuation rate at 8.7% (11 of 126 pts). Conversely, 56% (277 of 491 pts) of White patients received at least one supportive therapy, yet had the highest 1 year discontinuation rate at 17% (83 of 491 pts). Conclusions: Supportive therapies are essential to help patients mitigate side effects of AI. Patients who received at least one supportive therapy had increased rates of AI adherence beyond 1 year compared to those who did not receive any supportive treatment. The most commonly used therapies were bone strengthening agents and acupuncture. Use of acupuncture and low dose oxybutynin have increased in the past 3 years and 2 years, respectively, following publication of their efficacy. It is critical to further evaluate the impact that race and age have in relation to duration of treatment and use of supportive management. Further studies on how to improve patient tolerability and adherence to AI therapy are needed. Citation Format: Melanie W Kier, Zhiqiang Li, Brittney S Zimmerman, Rima Patel, Yunchen Yang, Mark Y Fink, Jason D Wells, Xiang Zhou, Scott Newman, Rong Chen, Eric Schadt, William Oh, Amy Tiersten. Impact of supportive therapies on tolerance of aromatase inhibitors in patients with early-stage, hormone-positive breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P5-18-11.