Nationwide real‑world data on tumor‑agnostic genomic companion diagnostics and comprehensive genomic profiling tests

The present study aimed to assess the utilization of biomarker testing, including companion diagnostics and comprehensive genomic profiling (CGP), in Japan and to highlight the value of large‑scale real‑world database analysis in precision oncology. Claims data from the Medical Data Vision Co., Ltd. database, covering ~40 million patients across 26% of advanced treatment hospitals in Japan, were retrospectively analyzed. Biomarker tests for five genomic biomarkers (BRAF, BRCA1/2, KRAS/NRAS, homologous recombination deficiency and microsatellite instability (MSI)) were evaluated in patients with a confirmed diagnosis of one of 11 common cancer types, a cancer of unknown primary origin (CUP) or a rare cancer, who underwent at least one biomarker test between December 2018 and March 2022. A total of 41,191 biomarker tests were recorded in 28,382 patients, with test volumes increasing markedly between 2018 and 2021. MSI testing was the most common (70.1% of patients), followed by RASKET‑B for KRAS/NRAS (25.5%) and BRAF (23.9%). Patients with colorectal cancer frequently underwent multiple tests (42.8%) and distinct testing sequences were observed in gynecological cancer. CGP was more commonly performed on tissue‑based samples than through liquid biopsy, particularly in rare cancer (38.5%) and CUP (11.4%). Notably, ~40% of patients received a new treatment after CGP, whereas only 1.7% initiated indicated therapy after MSI testing. The mean time to subsequent treatment initiation from the index date was 70.4 days. In conclusion, the present nationwide real‑world study provides an early comprehensive overview of the prevalence and trends of biomarker testing in Japan, and reveals a gap between testing and treatment implementation. Although testing is increasing, its effective clinical use remains limited. Large‑scale database analyses may help identify barriers and support strategies to improve the integration of biomarker testing into treatment decision‑making, ultimately advancing precision oncology.