Precision Oncology in Clinical Practice: Two Years of Comprehensive Genomic Profiling in Croatia

Background: The widespread adoption of precision medicine in routine cancer care remains a critical challenge, even as advanced technologies expand and personalized therapies demonstrate remarkable success in certain cancer types. While breakthrough innovations in targeted treatments have revolutionized outcomes for specific cancers, translating these scientific advances into standard clinical practice continues to be an evolving and complex endeavor. Croatia has a nationwide project of precision oncology through the comprehensive genomic profiling (CGP) analysis. Since collecting and analyzing real-world data is crucial for clinical research and defining the value of CGP in precision oncology, we aimed to present the data from everyday clinical practice given the opportunities and challenges we faced. Methods: This was a retrospective observational study conducted at the national level in all patients whose tumor samples were subjected to CGP between 1 January 2020 and 31 December 2021. Results: In total, 481 patients with CGP results were included in this study. Gastrointestinal and reproductive malignancies were the most common, accounting for 29.1% and 28.9% of all tested tumors, respectively. Specifically, colorectal tumors made up 19.1% of cases, while uterine tumors represented 11.2%. At least one clinically relevant genomic alteration was found in 76.7% of patients, with the KRAS mutation (27.2%) being the most common. During the two-year study period, 26,709 individuals lost their lives to cancer in Croatia. Combining this with the CGP selection criteria valid at the time, there was an estimated population of approximately 13,350 potentially eligible patients for the CGP analysis, meaning that only 3.6% of potentially eligible patients were tested. Conclusions: The analysis identified clinically actionable genomic alterations in approximately 80% of the evaluated patients, suggesting they could be candidates for targeted therapeutic interventions. The adoption of CGP remains limited, with estimates indicating that under 5% of metastatic cancer patients received testing in the initial two-year implementation period, despite established national insurance coverage guidelines. This low utilization rate suggests a significant gap in access to genomic testing, leaving many eligible cancer patients without the potential benefits of this diagnostic approach.