Conventional chemotherapy regimens have shown only marginal success in extending survival for dogs with hemangiosarcoma, highlighting an urgent need for more effective treatment strategies. While targeted therapies have transformed human oncology, their adoption in veterinary medicine remains limited, partly due to challenges in recruiting sufficient cases of rare cancers. This study addressed this gap by analyzing real-world clinical data from dogs with naturally occurring splenic HSA, utilizing next-generation sequencing to uncover actionable genomic markers. The findings reveal critical associations between somatic mutations and therapeutic outcomes, providing a foundation for precision medicine in veterinary oncology.
Key discoveries emerged regarding prognostic genetic alterations and targeted therapy efficacy. Mutations in the tumor suppressor PTEN were strongly predictive of poor survival, outperforming even TP53 as a negative prognostic marker, while activating NRAS mutations correlated with improved overall survival, suggesting these tumors may follow a distinct, less aggressive biological program. Notably, dogs receiving targeted therapies showed significantly better outcomes, with ATRX mutations serving as a particularly robust genomic marker for treatment response across therapeutic classes. These results underscore the potential of molecular profiling to guide clinical decision-making in hemangiosarcoma.
The current standard of care for canine HSA—surgical resection followed by doxorubicin-based chemotherapy—provides limited benefits, primarily in stage II disease. The data confirmed that doxorubicin improves survival compared to surgery alone but remains ineffective for advanced-stage HSA. Targeted therapies demonstrated comparable efficacy to doxorubicin in stage II cases, but the most substantial survival benefit occurred when both modalities were combined. Though not statistically significant in stage III disease, a positive trend aligned with observations in human angiosarcoma (AS), where doxorubicin responses are often transient.
The integration of NGS enabled a deeper investigation into how somatic mutations influence survival. Their Cox proportional-hazards model identified PTEN, TP53, and NRAS as key drivers of differential outcomes—genes frequently altered in human angiosarcoma. These findings challenge the current “one-size-fits-all” chemotherapy paradigm, advocating instead for biomarker-driven therapy. Of particular translational relevance, ATRX mutations predicted targeted therapy response in dogs, suggesting potential cross-species clinical applications.
One of the most clinically actionable findings was the efficacy of rapamycin in dogs with PIK3CA or TP53 mutations. This mTOR inhibitor could be repurposed as a standard adjuvant for genetically selected cases, independent of other therapies in the regimen. Such targeted approaches align with the broader shift toward personalized medicine, where treatment decisions are increasingly informed by tumor genetics rather than histology alone.
Together, these results demonstrate that precision oncology can deliver measurable survival benefits for dogs with HSA. Beyond advancing veterinary care, the study reinforces the power of comparative oncology: canine cancers not only mirror human disease biology but also serve as a platform to evaluate novel therapeutics in a natural disease setting.
Future efforts should focus on expanding targeted therapy options, validating these biomarkers in larger cohorts, and fostering bidirectional translation between human and veterinary medicine to accelerate breakthroughs for both species.
