143 Patient Experience With Intramuscular Vs Oral Endocrine Therapy in Metastatic Breast Cancer

Background

This study reported metastatic breast cancer patients’ experiences with endocrine therapy (ET) by describing the burdens (including challenges to administration and adherence), benefits, and preference of oral and IM (intramuscular) ET.

Method

US-based adults with a history of taking both oral and IM ET consecutively for 3 or more months completed an online survey. Participants were recruited via email and in-person at Cancer Support Community’s national network of 190 locations and 14 advocacy groups. Treatment-related considerations on a 5-point scale of burden vs benefit, and preference for oral vs IM ET were assessed. Participants also rated the importance of 11 factors when considering their metastatic breast cancer treatment options.

Results

Data included responses from 157 women with metastatic breast cancer: mean age of 53 years (SD = 11.8); 66% non-Hispanic White; 13% Black or African American; 29% urban; and average time since metastatic diagnosis of 5.9 years. Approximately 58% participants lived 30 or more minutes away from a treatment center. Median duration on ET was longer for oral (24 months) vs IM (15 months); 65% received oral prior to IM ET. Over 80% of participants found oral ET less painful, required less transportation and time, and more convenient. Most (67%) reported oral ET interfered less with daily life vs IM (17%). Top benefits of oral ET were ease of access (72% [major or minor benefit]), minimal time commitment (62%), and convenience (57%), while the stress or anxiety associated with daily medication consumption was the most common burden (45% [major or minor burden]). For IM ET, the main benefit reported was ease of remembering (53%), while the most frequently reported burden was injection pain or discomfort (84%). Self-reported adherence was better for IM vs oral ET, with 70% and 52% reporting they never missed a single dose, respectively. Among the 48% that missed ≥1 dose for oral ET, 68% missed ≤2 times a month. Approximately 96% found the treatment’s ability to slow disease progression an important priority, followed by the ability to cure the disease (89%).

Conclusions

Findings suggest participants preferred oral over IM ET, due to ease of access, convenience, and minimal daily life disruption. However, daily oral medication was associated with stress and anxiety for some. Although self-reported adherence was better for IM ET, missing a single dose has different implications for the IM ET, given every 28 days, rather than daily oral ET. These findings support the need for shared decision-making to help ensure treatment decisions are optimized with patient preferences.

Previously presented at SABCS 2025
Sponsored by Eli Lilly and Company