Abstract PO2-05-02: Real-world experience of patients receiving treatment for hormone receptor-positive/human epidermal growth factor receptor-2 negative metastatic breast cancer: A global analysis of symptoms and side effects
Authors: Rehnquist MK , Partridge Ann , Lambert Annabel , Kurian Allison , Sadetsky Natalia , Freeman Emily , Carey Lisa 
Published: May 2024

Abstract
Background: Advances in treatment for patients (pts) with hormone receptor-positive (HR+)/human epidermal growth factor receptor-2 negative (HER2–) metastatic breast cancer (mBC) have improved overall survival, but treatment resistance is common and median survival remains only a few years. These pts usually need chronic therapy and often experience symptoms and side effects. There is limited knowledge on pts’ experiences outside the clinical trial setting, largely because this information is not routinely reported. This analysis leverages a unique database of physician- and pt-reported data to describe symptoms and side effects among a real-world, geographically diverse population of pts receiving treatment for HR+/HER2– mBC. Methods: This retrospective cohort study used Adelphi Disease Specific Programme Real World Data, comprising validated, linked pt and physician questionnaire data from the US, France, Germany, Italy, Spain, and UK. Eligible pts were ≥18 y, currently receiving treatment for advanced BC and not enrolled in a clinical trial. Data were collected between August 2022 and February 2023. Physician surveys provided data on individual pt demographics and disease characteristics, comorbidities, treatment history, and treatment (including adherence). Physicians also reported presence or absence of symptoms and side effects after treatment initiation for each pt they considered. A subset of pts completed one-time validated quality of life (QOL) instruments, including the European Organisation for Research and Treatment of Cancer Core Quality of Life Questionnaire (EORTC QLQ-C30) and EORTC QLQ-breast (BR23). Results: Data from 1578 pts receiving treatment for HR+/HER2– mBC were analyzed. Mean age was 65-y, 91% were white, 71% had de novo mBC, and 82% had ECOG performance status 0-1 at the start of current treatment. Across all lines of therapy, 71% of pts were receiving endocrine-based therapy, 16% were receiving chemotherapy only, and 13% were receiving other therapies; 40% of all pts were receiving second or later lines of any systemic therapy (2L+). Among all pts, the most common physician-reported symptoms and side effects (in ≥10% of pts) were bone pain (30%), change in appetite (13%), weight loss (12%), neutropenia (11%), and joint/muscle pain (11%). Pts on 2L+ therapy experienced a greater frequency of symptoms and side effects than those on first-line therapy (Table). Of 220 pts who completed QOL questionnaires, the most commonly reported symptoms and side effects (in ≥70% of pts) were feeling tired (87%), worry about future health (80%), general worrying (79%), needing to rest during the day (74%), feeling weak (74%), having trouble doing strenuous activity (71%), and trouble taking a long walk (71%). These were common irrespective of pt age, disease state (recurrent vs de novo), current treatment regimen, and line of therapy. Conclusions: This real-world analysis shows that both physicians and pts identified substantial symptoms and side effects during treatment. These were pervasive across the population and more common in those receiving 2L+ therapy, although it remains unclear which were due to treatment or disease. Thus, it is important to continue to develop treatments and supportive care to improve both clinical outcomes and pt QOL.

Citation Format: MK Rehnquist, Ann Partridge, Annabel Lambert, Allison Kurian, Natalia Sadetsky, Emily Freeman, Lisa Carey. Real-world experience of patients receiving treatment for hormone receptor-positive/human epidermal growth factor receptor-2 negative metastatic breast cancer: A global analysis of symptoms and side effects [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-05-02.