Real-world treatment patterns of hormone receptor-positive and human epidermal growth factor receptor 2-negative advanced breast cancer.

Introduction: The HABER study aimed to evaluate real-world treatment patterns for hormone receptor-positive, HER-2-negative (HR+/HER-2-) advanced breast cancer (ABC) in Poland, focusing on adherence to local and international guidelines. Material and methods: This retrospective, non-interventional analysis included 440 patients treated between September 2020 and August 2021 across 17 clinical sites. The trial was registered with ClinicalTrials.gov, NCT05478590. Results: Most patients were postmenopausal (76.7%) with a mean age of 62.7 years, and nearly two-thirds had comorbidities. Almost half of the patients (48.6%) were diagnosed with de novo ABC. CDK4/6 inhibitor-based therapies were the predominant first-line treatment (74.1%), aligning with guideline recommendations. These therapies were more frequently combined with aromatase inhibitors (64.7%) than with fulvestrant (35.3%). The mean age ± standard deviation of patients treated with endocrine therapy (71.8 ±11.6 years) was higher than the age at which they received CDK4/6 inhibitors with endocrine therapy (61.3 ±11.7 years) or chemotherapy (62.0 ±13.2 years), Conclusions: Treatment choice was influenced by patient demographics, performance status, and time from early breast cancer to relapse. The observed treatment patterns of first-line treatment of HR+/HER- ABC are highly aligned with current national and international guidelines.