# Casuistry of oncological diseases in dogs, focusing on bone tumors treated at the Veterinary Hospital of the University of the Republic, Uruguay (2018–2023)

## TL;DR

This study analyzed 963 cases of canine cancer in Uruguay, finding that skin tumors were most common, with osteosarcoma being the main bone tumor in large dogs.

## Contribution

The study provides updated epidemiological data on canine cancer in Uruguay, highlighting breed, sex, and age trends.

## Key findings

- Skin and subcutaneous tumors were the most frequently diagnosed, followed by musculoskeletal and hemolymphatic tumors.
- Osteosarcoma was the most common bone tumor, primarily affecting large breeds and the forelimbs.
- Spayed females had higher rates of musculoskeletal tumors, while intact males were more prone to skin tumors.

## Abstract

Cancer is an important cause of morbidity and mortality in the geriatric canine population; however, there are no updated epidemiological data in Uruguay. In this retrospective study, 963 cases of canine cancer diagnosed between 2018 and 2023 at the Veterinary Hospital Center of the Faculty of Veterinary Medicine (VHC–FVM), Uruguay, were analyzed. Data were collected from medical records and analyzed using descriptive statistics and chi-square tests to assess associations between demographic variables and tumor distribution. Neoplasms of the skin and subcutaneous tissue were the most frequently diagnosed, followed by musculoskeletal and hemolymphatic tumors. A higher proportion of cases were observed in females, most of which were spayed. Skin tumors were more common in intact males, whereas spayed females were more frequently affected by musculoskeletal tumors. The highest number of cases occurred in dogs aged 6 to 10 years, followed by those older than 11 years, and the lowest frequency was observed in dogs aged 0 to 5 years. Among bone tumors, osteosarcoma was the most common type, affecting mainly large breeds and predominantly the appendicular skeleton, particularly the forelimbs. These findings emphasize the importance of considering sex, age, reproductive status, and race in cancer surveillance. From a clinical perspective, such information can guide early diagnosis strategies, improve case follow-up, and support preventive initiatives. In addition, the establishment of local and regional cancer registries is essential for advancing veterinary oncology research and strengthening the understanding of cancer epidemiology in Latin America.