Cancer genomic data systems in precision oncology: from integration to clinical implementation.

Cancer genomic data sharing is a core pillar of precision oncology, underpinning reproducibility, scalability, and equity. The ability to discover, access, integrate, interpret, and reuse cancer 'omics data is a key determinant of precision oncology's value and benefit at scale. This work has been conducted as part of The Lancet Oncology Commission on Cancer Genomics and Precision Oncology to examine the practical data architecture required to support cancer genomics in research, clinical care, and health-system learning. We conclude that without robust data stewardship, including effective data sharing and global integration, the potential of cancer genomics will remain fragmented across projects, platforms, and jurisdictions. This disaggregation limits reproducibility, equity, patient benefit, and societal value. Healthcare systems must prioritise implementing fully efficient data ecosystems as a central challenge for precision oncology.