title: Appendicular osteosarcoma in small-breed dogs: 51 cases (1986-2011).
abstract: OBJECTIVE
  To describe outcomes for small-breed dogs with appendicular osteosarcoma.
  
  
  METHODS
  Multi-institutional retrospective case series.
  
  
  METHODS
  51 small-breed dogs.
  
  
  METHODS
  Records from participating Veterinary Society of Surgical Oncology members were searched for dogs that weighed ≤ 15 kg (33 lb) with a histologic diagnosis of appendicular osteosarcoma. The Kaplan-Meier method was used to determine median survival times (MSTs), and Cox regression was performed to identify variables associated with survival time.
  
  
  RESULTS
  Tumors were most commonly located on the humerus (n = 15) and femur (14). Of the 51 study dogs, 9 were treated nonsurgically, 16 underwent amputation of the affected limb only, and 26 underwent curative-intent treatment, with MSTs of 112, 257, and 415 days, respectively. The MST did not differ significantly between dogs in the amputation-only and curative-intent groups. For dogs in the nonsurgical group, MST decreased significantly as the tumor histologic score increased. For dogs in the amputation-only group, MST decreased as body weight increased.
  
  
  CONCLUSIONS
  For the small-breed dogs with appendicular osteosarcoma of the present study, tumor histologic grade and mitotic index were subjectively lower and MST following amputation of the affected limb without adjuvant chemotherapy was longer, compared with those for similarly affected larger dogs. Results indicated no significant advantage in MST for dogs that underwent curative-intent treatment versus dogs that underwent amputation only, and further investigation of the importance of adjuvant chemotherapy is warranted.
authors.affiliation: Departments of Companion Animals, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, C1A 4P3, Canada.
authors.forename: Pierre M
authors.initials: PM
authors.lastname: Amsellem
authors.forename: Laura E
authors.initials: LE
authors.lastname: Selmic
authors.forename: Jackie M
authors.initials: JM
authors.lastname: Wypij
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Bacon
authors.forename: William T N
authors.initials: WT
authors.lastname: Culp
authors.forename: Nicole P
authors.initials: NP
authors.lastname: Ehrhart
authors.forename: Barbara E
authors.initials: BE
authors.lastname: Powers
authors.forename: Henrik
authors.initials: H
authors.lastname: Stryhn
authors.forename: James P
authors.initials: JP
authors.lastname: Farese
mesh_terms: D000671:Amputation, Surgical / Q000662:veterinary*; D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D049628:Body Size; D004283:Dog Diseases / Q000473:pathology / Q000628:therapy*; D004285:Dogs; D005121:Extremities / Q000473:pathology*; D012516:Osteosarcoma / Q000188:drug therapy / Q000601:surgery / Q000662:veterinary*; D012189:Retrospective Studies
chemical_list: D000970:Antineoplastic Agents