Treatment and outcomes of patients with HR+/HER2− early breast cancer in a real-world setting in Germany

BACKGROUND: A subset of patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative early breast cancer (HR+/HER2- EBC) are at higher risk of disease recurrence. MATERIALS AND METHODS: This study utilised real-world data from the German Tumour Registry Breast Cancer (TMK I/II, recruiting patients with EBC on systemic therapy during 2007-2010/2011-2014 with follow-up until 2019/2021, respectively) to evaluate the proportion of patients with HR+/HER2- EBC who are at high risk of recurrence according to the following criteria: ≥4 positive ipsilateral axillary lymph nodes (pALNs), or 1-3 pALNs plus either histologic grade 3 disease or tumour size ≥5 cm. Furthermore, it compared demographic and clinical characteristics, treatment patterns and survival outcomes of patients with and without those high-risk characteristics. RESULTS: Of 1107 patients with HR+/HER2- EBC, 270 patients (24.4%) had high-risk disease (median age 57.3 years). Neoadjuvant/adjuvant chemotherapy was documented for 98.5% and 88.8% of patients in the high-risk and non-high-risk cohort, respectively. The 3-year and 5-year invasive disease-free survival in the high-risk cohort were 79.0% and 68.8%, respectively, vs 92.6% and 88.9%, respectively, in the non-high-risk cohort, with corresponding values for distant recurrence-free survival of 81.5% and 71.0%, respectively, vs 94.4% and 91.4%, respectively. The 3-year and 5-year overall survival were 95.9% and 85.6%, respectively, for the high-risk cohort vs 97.3% and 94.4%, respectively, for the non-high-risk cohort. CONCLUSION: A considerable subset of patients with HR+/HER2- EBC present with high-risk clinicopathological characteristics, which indicate a negative impact on prognosis, thus highlighting the need for novel treatment strategies for this patient population.