FEASIBILITY OF CONSTRUCTING HR+/HER2- METASTATIC BREAST CANCER COHORTS INCORPORATING TREATMENT SEQUENCING IN A JAPANESE MULTICENTER ONCOLOGY EMR DATABASE
Author(s)
Kuzuya Motoki, MS1, Shigemi Matsumoto, MD, PhD2, Tomoki Saito, MD, PhD2, Ayanori Fukushima, BS1, Dimitra Lambrelli, MASc, MSc, PhD3, Tadashi Koga, PhD4, Masafumi Okada, MD, PhD5, Manabu Muto, MD, PhD2.
1Prime Research Institute for Medical RWD, Inc., Kyoto, Japan, 2Kyoto University Hospital, Kyoto, Japan, 3Thermo Fisher Scientific, London, United Kingdom, 4Clinical Study Support, Inc., Nagoya, Japan, 5NTT Precision Medicine, Tokyo, Japan.
1Prime Research Institute for Medical RWD, Inc., Kyoto, Japan, 2Kyoto University Hospital, Kyoto, Japan, 3Thermo Fisher Scientific, London, United Kingdom, 4Clinical Study Support, Inc., Nagoya, Japan, 5NTT Precision Medicine, Tokyo, Japan.
OBJECTIVES: Endocrine therapy (ET) combined with cyclin-dependent kinase 4/6 (CDK4/6) inhibitors is a standard option for hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+/HER2−) advanced/metastatic breast cancer. Japanese real-world studies have described treatment patterns and outcomes among patients receiving CDK4/6 inhibitors; however, claims-based studies often have limited access to biomarker results, laboratory values, and detailed treatment pathways. J-CONNECT is a Japanese multicenter oncology database linking hospital-based cancer registry data with electronic medical records, including treatment, laboratory, and selected biomarker information. This study assessed the feasibility of constructing biomarker-defined HR+/HER2− metastatic breast cancer cohorts incorporating ET exposure and CDK4/6 inhibitor use in J-CONNECT.
METHODS: We conducted a retrospective feasibility assessment using J-CONNECT. Sequential cohort construction was performed for breast cancer cases, stage IV/metastatic breast cancer, ET-treated patients, HR/HER2-defined subgroups, and CDK4/6 inhibitor-treated or untreated cohorts. Feasibility domains included HR/HER2 availability, treatment exposure, treatment sequencing, and selected baseline laboratory variables.
RESULTS: Among 8,017 breast cancer cases, 466 (5.8%) had stage IV/metastatic disease, of whom 291 (62.4%) received ET. HR and HER2 status were available for 74.9% and 74.2% of eligible patients, respectively. Among patients with classifiable HR/HER2 subtype, HR+/HER2− disease accounted for 160 (86.5%) and HER2+ disease for 25 (13.5%). Among ET-treated HR+/HER2− patients, 128 (80.0%) were treated with CDK4/6 inhibitors and 32 (20.0%) were not. At least one selected baseline laboratory value was available for 92.2% of patients, with institutional variation ranging from 78.2% to 100.0%. These findings demonstrate that biomarker-defined metastatic breast cancer cohorts incorporating treatment sequencing can be constructed within J-CONNECT.
CONCLUSIONS: J-CONNECT can support construction of clinically meaningful biomarker-defined metastatic breast cancer cohorts incorporating ET exposure and CDK4/6 inhibitor use in Japan. These findings position J-CONNECT as a clinically detailed RWD platform for evaluating precision oncology research feasibility beyond what is typically possible using claims data alone.
METHODS: We conducted a retrospective feasibility assessment using J-CONNECT. Sequential cohort construction was performed for breast cancer cases, stage IV/metastatic breast cancer, ET-treated patients, HR/HER2-defined subgroups, and CDK4/6 inhibitor-treated or untreated cohorts. Feasibility domains included HR/HER2 availability, treatment exposure, treatment sequencing, and selected baseline laboratory variables.
RESULTS: Among 8,017 breast cancer cases, 466 (5.8%) had stage IV/metastatic disease, of whom 291 (62.4%) received ET. HR and HER2 status were available for 74.9% and 74.2% of eligible patients, respectively. Among patients with classifiable HR/HER2 subtype, HR+/HER2− disease accounted for 160 (86.5%) and HER2+ disease for 25 (13.5%). Among ET-treated HR+/HER2− patients, 128 (80.0%) were treated with CDK4/6 inhibitors and 32 (20.0%) were not. At least one selected baseline laboratory value was available for 92.2% of patients, with institutional variation ranging from 78.2% to 100.0%. These findings demonstrate that biomarker-defined metastatic breast cancer cohorts incorporating treatment sequencing can be constructed within J-CONNECT.
CONCLUSIONS: J-CONNECT can support construction of clinically meaningful biomarker-defined metastatic breast cancer cohorts incorporating ET exposure and CDK4/6 inhibitor use in Japan. These findings position J-CONNECT as a clinically detailed RWD platform for evaluating precision oncology research feasibility beyond what is typically possible using claims data alone.
Conference/Value in Health Info
2026-11, ISPOR Europe 2026, Vienna, Austria
Value in Health, Volume 29, Issue 12S
Code
RWD127
Topic
Real World Data & Information Systems
Topic Subcategory
Data Protection, Integrity, & Quality Assurance, Health & Insurance Records Systems
Disease
Oncology, Personalized & Precision Medicine