Abstract
ObjectiveTo report demographic characteristics of a contemporary population of dogs with appendicular osteosarcoma and assess the relationship between demographic characteristics, site distribution, and phylogenetic breed clusters.DesignRetrospective case series.MethodsA search of the Veterinary Medical Database was performed for dogs with appendicular osteosarcoma as a new diagnosis. Entries were reviewed for the sex, neuter status, age at diagnosis, breed, affected limb, and tumor location. The reported breed for purebred dogs was used to categorize each dog into one of five phylogenetic groups based on microsatellite analysis.Results744 client-owned dogs were included in the study. Study dogs were represented by a male-to-female ratio of 0.95:1.0, the majority of which (80.9%) were neutered. Most dogs were diagnosed between 7–10 years of age. The majority (77.8%) of dogs were large or giant-breed dogs. Purebred dogs comprised 80.4% of the population. The most common purebred breed affected by OS was the Rottweiler (17.1%). The most common phylogenetic group represented was Mastiff-Terrier (M-T, 26.3%). OS was more commonly located in the forelimb (64.2%) versus the hindlimb (35.8%), and the humerus was the most common site (20.9%). The distribution of age groups and tumor locations were significantly different between phylogenetic clusters. The distribution of age groups and neuter status were significantly different between size groups.Conclusions and significanceThe demographic data of canine appendicular OS are similar to previous reports. The data on phylogenetic associations can guide future studies aimed at evaluating the genomic mutations that contribute to OS development and its biological behavior.
Highlights
A search of the Veterinary Medical Database was performed for dogs with appendicular osteosarcoma as a new diagnosis
The demographic data of canine appendicular OS are similar to previous reports
The demographic characteristics from populations of dogs affected by appendicular OS have been extensively described, with some reports dating back decades.[1,2,3,4,5, 11]
Summary
Osteosarcoma (OS) is the most common canine primary bone tumor and represents up to 85% of all primary malignant bone tumors in the dog.[1,2,3,4,5] Osteosarcoma of the appendicular skeleton occurs more commonly than OS of the axial skeleton.[3, 6,7,8,9,10] The demographic characteristics from populations of dogs affected by appendicular OS have been extensively described, with some reports dating back decades.[1,2,3,4,5, 11] Studies report appendicular OS to be largely a disease of middle-aged to older dogs with the median age at diagnosis generally ranging from 6 to 9 years.[2,3,4, 8, 10, 12,13,14,15,16] Males have been over-represented in some reports but this finding has not been supported in other reports.[2, 3, 7,8,9,10, 12,13,14,15,16,17,18] Endogenous sex hormones may play a role in sarcomagenesis–some studies have identified significantly increased risk of developing OS in neutered compared to intact dogs.[13, 19,20,21] Appendicular OS has been commonly reported in large and giant breed dogs, with increased incidence of disease in certain breeds including boxers, Great Danes, Rottweilers, Saint Bernards, Irish setters, Doberman pinschers, greyhounds, German shepherds, Irish wolfhounds and Leonbergers.[1, 3, 8, 11,12,13,14, 18, 21,22,23,24,25,26] An increased risk of OS development has been identified with increasing weight, height and age.[13] Appendicular OS occurs predominantly at the metaphyses of long bones and affects the bones of the forelimb more commonly than the hindlimb.[3, 7, 15, 22, 27] The distal portion of the radius and the proximal portion of the humerus are the most commonly affected sites.[2, 3, 7, 14, 16, 18, 20, 25, 28] The pathogenesis of canine OS and underlying factors driving its phenotypic manifestations are not well understood
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