Clinical Outcomes of Patients with Colorectal Cancer Who Underwent Comprehensive Genomic Profiling: A Single-institution Non-comparative Prospective Observational Study

Objectives: Although some studies have evaluated the effectiveness of comprehensive genomic profiling (CGP) in solid tumors, the effectiveness of CGP in metastatic colorectal cancer (mCRC) has not been evaluated using detailed real-world long-outcome data. Methods: This was part of a single institutional non-comparative prospective observational study that observed all patients with solid tumors who underwent CGP at Saitama Medical Center, Saitama Medical University. We enrolled patients with mCRC between June 4, 2020, and March 31, 2023. The primary endpoint was the proportion of patients who received CGP-based therapy. Results: There were 43 patients with mCRC. Of these, six patients (14.0%) received CGP-based therapy. The median overall survival from CGP testing in patients who received CGP-based therapy was 9.7 months. The progression free survival (PFS) ratio of CGP-based therapy and immediate previous therapy ranged from 0.04 to 2.0. The PFS ratio >1.5 was 14.3% (one out of seven treatments). One patient exhibited an exceptional response to pembrolizumab. Before CGP testing, the patient's cancer was classified as non-microsatellite instability-high, although the CGP test revealed a high tumor mutational burden. In Japan, patients with this subtype cannot undergo pembrolizumab without testing for CGP. Conclusions: This prospective observational study's findings provide an overview of CGP testing outcomes in patients with refractory mCRC.