e15526 Background: As the third most prevalent and third leading cause of cancer-related deaths in the US, colorectal cancer (CRC) represents a significant healthcare challenge. Approximately 20% of patients with CRC are diagnosed with metastatic CRC (mCRC), and outcomes for these patients are often poor. While guidelines recommend comprehensive biomarker testing for all patients with mCRC, evidence on adoption of biomarker testing, especially across lines of therapy (LoT), remain limited. This analysis describes biomarker testing and rebiopsy patterns across LoT using large, national, electronic medical records data from US-based patients with mCRC. Methods: This was a retrospective analysis of patient data using the ConcertAI Patient360 database to assess biomarker testing patterns. For inclusion, patients had to be adults with unresectable mCRC diagnosed between the years 2013–2024, who also had evaluable longitudinal data captured in the first-line (1L)+ treatment setting; patients were excluded if they had multiple concurrent primary cancers and if their date of metastasis was within 30 days of data end. Outcomes included biomarker testing and biopsy rates by LoT and year of testing. Results: Of 1817 patients included in these analyses, 1817, 916, and 495 had data available at 1L, second-line (2L), and third-line (3L), respectively. Patient characteristics were consistent across LoT; patients had a median age of 61–62 years and were mostly White, male, and treated in community settings. Testing for any biomarker occurred in 1391 (77%) patients at 1L; testing rates dropped sharply in later LoT, with 428 (47%) patients tested at 2L, and 149 (30%) patients tested at 3L. Within each LoT, testing rates increased in more recent years; testing rates in 2013−2016 vs 2023−2025 were 62% vs 91% at 1L, 30% vs 57% at 2L, and 21% vs 40% at 3L. At 1L, tissue was most frequently used for testing (n=1350; 74%), this trend continued in 2L and 3L settings; however, the proportion of patients receiving any biopsy for biomarker testing drops to 25% (n=233) and 16% (n=79) at 2L and 3L, respectively (Table). Conclusions: In this real-world analysis of patients with mCRC, while biomarker testing rates at 1L increased in more recent years, rates overall are still relatively low at 2L and 3L. Additionally, while tissue was commonly used for testing at 1L, use of tissue dropped in later LoT. These data suggest that standardization of biomarker testing planning is needed to ensure optimal patient access to biomarker-driven therapies in 1L and later LoT for all patients with mCRC. Biomarker testing and biopsy rates across LoT. 1L(N=1817) 2L(n=916) 3L(n=495) Tested for LoT 1391 (76.6) 428 (46.7) 149 (30.1) Biopsy (any type) 1413 (77.8) 233 (25.4) 79 (16.0) Blood 244 (13.4) 82 (9.0) 37 (7.5) Cytology 3 (0.2) 0 3 (0.6) Tissue 1350 (74.3) 170 (18.6) 40 (8.1) Data are n (%).
Kolhe et al. (Thu,) studied this question.