Around 90% of breast cancer patients are diagnosed at an early stage and approximately 70% are hormone receptor-positive and HER2-negative (HR+/HER2-). Despite advancements in adjuvant endocrine therapy, 20-30% of early-stage breast cancer patients relapse within the first decade post-surgery. A recent clinically meaningful therapeutic option for these patients has been cyclin-dependent kinases 4/6 inhibitors (CDK4/6 inhibitors). Abemaciclib and ribociclib were assessed in the adjuvant setting, both showing improvement in invasive disease-free survival (IDFS). Abemaciclib has been approved by the FDA and EMA for HR+/HER2- early breast cancer at high risk of disease recurrence and is the first addition to the Slovenian treatment regimen in routine clinical practice. Poor medication adherence can directly affect the effectiveness of treatment for early HR+/HER2- breast cancer. While adherence data in patients treated with aromatase inhibitors are available, the adherence rate in patients with early HR+/HER2- breast cancer taking abemaciclib remains unclear. In this study, investigators hypothesize that patients receiving abemaciclib in combination with aromatase inhibitors will have lower medication adherence and higher discontinuation rates compared to those receiving aromatase inhibitors alone. It is expected that patients with better quality of life, better cognitive functioning, and a more positive attitude toward their therapy will demonstrate higher medication adherence rates. Adherence may also be influenced by additional factors, such as age and prior treatments.
Poor medication adherence can directly affect the effectiveness of treatment for early HR+/HER2- breast cancer. While data on medication adherence in patients taking aromatase inhibitors are available, the adherence rate in patients with early HR+/HER2- breast cancer taking abemaciclib remains unclear. Due to the differing characteristics of these treatment modalities, particularly their distinct safety profiles, medication adherence and persistence may vary between them. It is hypothesized that patients receiving abemaciclib in combination with aromatase inhibitors will have lower medication adherence and higher discontinuation rates compared to those receiving aromatase inhibitors alone. It is also expected that patients with better quality of life, better cognitive functioning, and a more positive attitude toward their therapy will demonstrate higher medication adherence rates. Additionally, factors such as age and prior treatments may contribute to adherence outcomes.
Study Type
OBSERVATIONAL
Enrollment
319
Institute of Oncology Ljubljana
Ljubljana, Slovenia
RECRUITINGMedication adherence (Proportion of Days Covered, PDC) at Month 3
Medication adherence measured as Proportion of Days Covered (PDC), calculated from pill count data and expressed as percentage (%). Participants with PDC ≥80% will be classified as adherent. Self-reported adherence will additionally be assessed using the Medication Adherence Report Scale (MARS-5; score range 5-25, higher scores indicate better adherence).
Time frame: Month 3 after treatment initiation
Medication adherence (Proportion of Days Covered, PDC) at Month 6
Medication adherence measured as Proportion of Days Covered (PDC), calculated from pill count data and expressed as percentage (%). Participants with PDC ≥80% will be classified as adherent. Self-reported adherence will additionally be assessed using the Medication Adherence Report Scale (MARS-5; score range 5-25, higher scores indicate better adherence).
Time frame: Month 6 after treatment initiation
EORTC QLQ-C30 score at Baseline
Quality of life assessed using the EORTC QLQ-C30 questionnaire. Scores are transformed to a 0-100 scale (higher scores on functional and global scales indicate better functioning; higher scores on symptom scales indicate greater symptom burden).
Time frame: Baseline visit
EORTC QLQ-C30 score at Month 3
Quality of life assessed using the EORTC QLQ-C30 questionnaire. Scores are transformed to a 0-100 scale (higher scores on functional and global scales indicate better functioning; higher scores on symptom scales indicate greater symptom burden).
Time frame: Month 3
EORTC QLQ-C30 score at Month 6
Quality of life assessed using the EORTC QLQ-C30 questionnaire. Scores are transformed to a 0-100 scale (higher scores on functional and global scales indicate better functioning; higher scores on symptom scales indicate greater symptom burden).
Time frame: Month 6
EORTC QLQ-BR23 score at Baseline
Quality of life assessed using the EORTC QLQ-BR23 questionnaire. Scores are transformed to a 0-100 scale (higher scores on functional scales indicate better functioning; higher scores on symptom scales indicate greater symptom burden).
Time frame: Baseline visit
EORTC QLQ-BR23 score at Month 3
Quality of life assessed using the EORTC QLQ-BR23 questionnaire. Scores are transformed to a 0-100 scale (higher scores on functional scales indicate better functioning; higher scores on symptom scales indicate greater symptom burden).
Time frame: Month 3
EORTC QLQ-BR23 score at Month 6
Quality of life assessed using the EORTC QLQ-BR23 questionnaire. Scores are transformed to a 0-100 scale (higher scores on functional scales indicate better functioning; higher scores on symptom scales indicate greater symptom burden).
Time frame: Month 6
Beliefs about Medicines Questionnaire (BMQ) score at Baseline
Beliefs about medicines assessed using the Beliefs about Medicines Questionnaire (BMQ). Items are rated on a 5-point Likert scale and summed to generate questionnaire scores.
Time frame: Baseline visit
Beliefs about Medicines Questionnaire (BMQ) score at Month 3
Beliefs about medicines assessed using the Beliefs about Medicines Questionnaire (BMQ). Items are rated on a 5-point Likert scale and summed to generate questionnaire scores.
Time frame: Month 3
Beliefs about Medicines Questionnaire (BMQ) score at Month 6
Beliefs about medicines assessed using the Beliefs about Medicines Questionnaire (BMQ). Items are rated on a 5-point Likert scale and summed to generate questionnaire scores.
Time frame: Month 6
FACT-Cog score at Baseline
Cognitive functioning assessed using the Functional Assessment of Cancer Therapy-Cognitive Function (FACT-Cog) questionnaire. Items are rated on a 0-4 scale and summed to generate domain and total scores (higher scores indicate better perceived cognitive functioning).
Time frame: Baseline visit
FACT-Cog score at Month 3
Cognitive functioning assessed using the Functional Assessment of Cancer Therapy-Cognitive Function (FACT-Cog) questionnaire. Items are rated on a 0-4 scale and summed to generate domain and total scores (higher scores indicate better perceived cognitive functioning).
Time frame: Month 3
FACT-Cog score at Month 6
Cognitive functioning assessed using the Functional Assessment of Cancer Therapy-Cognitive Function (FACT-Cog) questionnaire. Items are rated on a 0-4 scale and summed to generate domain and total scores (higher scores indicate better perceived cognitive functioning).
Time frame: Month 6
Adverse events during follow-up
Number of participants experiencing at least one adverse event and total number of adverse events recorded during follow-up. Adverse events will be summarized by severity and seriousness.
Time frame: From treatment initiation through Month 6
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