Molecular Testing Strategies and Their Impact on Treatment Decision in HR+/HER2- Metastatic Breast Cancer: A Real-World Analysis From German Centers
Author(s)
Kai Strobel, MSc, Lisa Merker, MSc, Lorenz Schmid, MSc, Dorothea Plundrich, PhD, Stefan Schilling, M.A., Markus Rückert, PhD.
TriNetX Oncology GmbH, Freiburg im Breisgau, Germany.
TriNetX Oncology GmbH, Freiburg im Breisgau, Germany.
OBJECTIVES: Molecular testing, particularly ESR1 mutation analysis, plays a critical role in guiding treatment sequencing for HR+/HER2- metastatic breast cancer (mBC). Despite increasing adoption, variability in testing methodologies and timing may impact clinical decision-making and treatment optimization.
METHODS: A retrospective, multi-center analysis was conducted on molecular testing patterns and treatment decisions in HR+/HER2- mBC patients in Q4 2024. Among 595 care relevant BC treating centers identified in a health care structure analysis in Germany, a representative sample of 52 centers (56% OBP, 33% NUH, 12% UH) based on treated patient proportions were selected. The study examined testing, preferences between liquid and tissue biopsy, and the timing of molecular assessments in relation to treatment initiation.
RESULTS: Reported patient numbers were projected to a total treated incidence of 4815 patients and prevalence of 15917 patients in Germany in Q4 2024. ESR1 testing rates were highest before 2nd and 3rd line initiation (69% and 64%) and are lower in later lines (4L+: 44%). Testing varied by healthcare setting, with implementation before 2nd line highest in non-university hospitals (74%), followed by office-based practices (70%) and university hospitals (57%). Despite the availability of liquid biopsy (81%), the use of tissue biopsy reached 19% of all tests. Among patients with confirmed ESR1 mutations in second line, who comprised 43% of the tested cohort, 82% received ESR1-targeting therapy.
CONCLUSIONS: This analysis reveals heterogeneity in ESR1 mutation testing practices across German healthcare institution types for HR+/HER2- mBC. The lack of testing before later lines of treatment underlines a gap in decision making when the ESR1 status can change over time. Despite liquid biopsy availability, substantial tissue biopsy use persists. While most ESR1-mutated patients received appropriate targeted therapy, 18% did not, highlighting opportunities to optimize testing protocols and treatment decision-making to improve personalized care.
METHODS: A retrospective, multi-center analysis was conducted on molecular testing patterns and treatment decisions in HR+/HER2- mBC patients in Q4 2024. Among 595 care relevant BC treating centers identified in a health care structure analysis in Germany, a representative sample of 52 centers (56% OBP, 33% NUH, 12% UH) based on treated patient proportions were selected. The study examined testing, preferences between liquid and tissue biopsy, and the timing of molecular assessments in relation to treatment initiation.
RESULTS: Reported patient numbers were projected to a total treated incidence of 4815 patients and prevalence of 15917 patients in Germany in Q4 2024. ESR1 testing rates were highest before 2nd and 3rd line initiation (69% and 64%) and are lower in later lines (4L+: 44%). Testing varied by healthcare setting, with implementation before 2nd line highest in non-university hospitals (74%), followed by office-based practices (70%) and university hospitals (57%). Despite the availability of liquid biopsy (81%), the use of tissue biopsy reached 19% of all tests. Among patients with confirmed ESR1 mutations in second line, who comprised 43% of the tested cohort, 82% received ESR1-targeting therapy.
CONCLUSIONS: This analysis reveals heterogeneity in ESR1 mutation testing practices across German healthcare institution types for HR+/HER2- mBC. The lack of testing before later lines of treatment underlines a gap in decision making when the ESR1 status can change over time. Despite liquid biopsy availability, substantial tissue biopsy use persists. While most ESR1-mutated patients received appropriate targeted therapy, 18% did not, highlighting opportunities to optimize testing protocols and treatment decision-making to improve personalized care.
Conference/Value in Health Info
2025-11, ISPOR Europe 2025, Glasgow, Scotland
Value in Health, Volume 28, Issue S2
Code
EPH164
Topic
Clinical Outcomes, Epidemiology & Public Health, Real World Data & Information Systems
Disease
Oncology