Nationwide Real-World Usage of Blood-Based (Liquid) Biomarker Testing in Japan

Despite the advances in precision oncology through biomarker testing, not all patients are able to benefit from treatment decisions guided by tissue-based testing like comprehensive genomic profiling (CGP). However, the application and integration of liquid biopsy testing into clinical practice has not been fully defined in Japan. Clinical records were retrieved from the data repository of the Center for Cancer Genomics and Advanced Therapeutics (C-CAT) in Japan. All records related to FoundationOne Liquid tests were evaluated from the database's inception in June 2019 to June 2023. Outcomes of interest included treatment patterns before and after testing, as well as mutations of interest. The seven most frequent tumor types (pancreas, prostate, biliary tract, bowel, lung, stomach and ovary) were stratified as part of subgroup analyses. Of 7461 patient records, the most prevalent cancers were pancreatic (24.5%), prostate (15.8%), and biliary tract (11.2%) cancers. Following molecular tumor board (MTB) review, 5.8% of cases received new treatments, predominantly targeted therapy (41.7%) and chemotherapy (40.9%), with 2.1% participating in clinical trials. Median durations from specimen collection to post-MTB treatment were 63 days. Tests for patients with bowel cancer (70/796; 8.8%) and lung cancer (57/695; 8.2%) received genotype-matched treatment most frequently, followed by tests for patients with prostate cancer (92/1182; 7.8%). Access to CGP in Japan appears more limited compared to other high-income countries. While CGP may be valuable for certain cancers, such as bowel, biliary, and prostate cancer, its benefit for other cancer types remains unclear.