# Canine Splenic Hemangiosarcoma: Biological Behavior, Clinical Challenges and Therapeutic Limitations

## TL;DR

Canine splenic hemangiosarcoma is a deadly tumor that is often diagnosed too late and has limited treatment options, leading to poor survival rates.

## Contribution

This review provides a comprehensive analysis of the biological behavior, diagnostic challenges, and therapeutic limitations of canine splenic hemangiosarcoma.

## Key findings

- The tumor is highly aggressive and often metastasizes before diagnosis.
- Current treatments like surgery and chemotherapy offer only modest survival benefits.
- Alternative therapies such as immunotherapy and targeted approaches have shown inconsistent results.

## Abstract

Splenic hemangiosarcoma is one of the most aggressive malignancies affecting dogs and frequently remains clinically silent until it precipitates acute intra-abdominal hemorrhage following splenic rupture. Due to the highly metastatic nature of this tumor, microscopic metastases are typically present at the time of diagnosis. Surgical excision combined with systemic chemotherapy represents the current standard of care; however, these interventions generally result in only modest prolongation of survival. Alternative strategies, including immunotherapeutic and targeted approaches, have been explored, but outcomes have been variable and inconsistent. This review summarizes the biological behavior of splenic hemangiosarcoma, outlines the principal diagnostic and therapeutic challenges, and discusses the factors contributing to the persistently poor prognosis despite advances in treatment.

Canine splenic hemangiosarcoma is a highly malignant vascular neoplasm and is among the most frequent and clinically relevant splenic tumors in dogs. Its biological behavior is characterized by rapid growth, marked invasiveness, and early metastatic dissemination, contributing to the poor prognosis commonly observed in affected animals. Clinically, splenic hemangiosarcoma often remains subclinical until acute presentation due to splenic rupture and hemoperitoneum, thereby substantially limiting opportunities for early diagnosis and timely therapeutic intervention. Despite advances in diagnostic imaging, surgical techniques, and the use of adjuvant chemotherapy, the impact of current therapeutic approaches on long-term survival remains limited. Splenectomy is primarily palliative for hemorrhage control, and adjuvant doxorubicin-based chemotherapy yields only modest improvements in median survival; alternative approaches (metronomic chemotherapy, immunotherapy, and targeted therapies) have not demonstrated consistent clinical benefit. This review summarizes the biological and pathophysiological features of canine splenic hemangiosarcoma, discusses the main clinical challenges associated with its diagnosis and staging, and critically reviews current therapeutic approaches and their limitations. By integrating biological behavior with clinical and therapeutic evidence, this article highlights the reasons why prognosis remains poor and underscores the need for more effective strategies to improve clinical outcomes in dogs with splenic hemangiosarcoma.