A study published in Nature has provided new insights into the evolutionary patterns of metastatic bladder cancer, showing that cancer spread may frequently occur from one metastatic site to another rather than directly from the original bladder tumor. The findings offer a detailed view of how metastatic tumors evolve across different anatomical sites and could inform future approaches to disease monitoring and treatment of advanced bladder cancer.
Bladder cancer is characterized by substantial genetic and histological heterogeneity, particularly in advanced disease. Several less common histological subtypes follow distinct clinical trajectories and may differ in their responses to treatment. However, the evolutionary mechanisms underlying these differences and the processes that drive metastatic progression remain incompletely understood.
The study analyzed 104 tumor samples from 20 patients enrolled in a rapid autopsy program conducted through the University of Washington and Fred Hutchinson Cancer Center. The program enabled researchers to collect the primary tumor together with multiple metastatic tumors from the same patients, allowing them to reconstruct the evolutionary relationships among tumors at different anatomical sites. The samples represented conventional urothelial carcinoma as well as plasmacytoid, squamous, neuroendocrine and sarcomatoid subtypes.
Genomic analyses revealed that metastasis-to-metastasis seeding was a prominent pattern of disease dissemination. Among 16 patients with high-quality matched sequencing data from primary and metastatic tumors, an early metastatic tumor was identified as the likely source of subsequent metastases in nine patients, whereas the primary tumor was the dominant source of metastatic spread in five patients. Around 13 of the 16 patients had at least one inferred metastasis-to-metastasis seeding event.
These findings suggest that metastatic disease may not develop solely through repeated dissemination from the original bladder tumor. Instead, once established, a metastatic tumor can acquire additional genomic alterations and subsequently seed new metastatic sites. Such sequential dissemination could contribute to increasing tumor heterogeneity and the development of biologically distinct or more aggressive metastatic populations. Imaging findings available for selected patients also supported the inferred temporal sequence of metastatic development.
The researchers identified substantial differences in the evolutionary characteristics of individual bladder cancer subtypes. Plasmacytoid and neuroendocrine tumors demonstrated early driver alterations associated with shorter survival, while the different histological subtypes showed distinct patterns of genomic evolution, transcriptional activity and tumor-microenvironment features. Plasmacytoid tumors displayed immune-inflamed characteristics, whereas squamous tumors showed predominantly immunosuppressive profiles, highlighting biological differences that may have implications for disease progression and therapeutic strategies.
The study also evaluated cell-free DNA (cfDNA) as a potential minimally invasive approach for characterizing metastatic disease. Post-mortem cfDNA captured most founder and pathogenic genomic alterations and reflected differences in transcriptional programs across histological and molecular subtypes. These observations suggest that blood-based molecular profiling could potentially provide information about tumor evolution and help identify emerging aggressive disease. However, the clinical utility of this approach remains to be established in larger prospective studies, particularly using samples collected longitudinally during treatment.
The observation that metastatic tumors can seed additional metastatic sites also raises questions about the timing and sequencing of treatment in patients with limited metastatic disease. In particular, controlling an early metastatic site could potentially influence subsequent dissemination if that site serves as a source for additional metastases. However, whether interventions directed at such sites can alter the natural history of metastatic disease remains an important question for future clinical investigation and should not yet be considered an established treatment strategy.
The study provides a detailed molecular and evolutionary framework for understanding metastatic bladder cancer. By integrating rapid-autopsy sampling with genomic sequencing, transcriptomic analysis and cfDNA assessment, the researchers demonstrated how metastatic tumors can evolve independently and contribute to further disease dissemination. The findings may help advance the development of molecular monitoring strategies and support future efforts to tailor the management of metastatic bladder cancer according to tumor subtype and evolutionary characteristics.
Reference
Itagi P, Schuster SL, Arora S, Persse TW, Waters JA, Yang M, et al. Evolution and heterogeneity of lethal metastatic bladder cancer subtypes. Nature. 2026. doi:10.1038/s41586-026-11035-z.