Canis ISSN: 2398-2942


Synonym(s): OSA

Contributor(s): Laura Garrett, Andy Moores


  • 85% of all bone tumors (50% of all bone tumors in small breeds).
  • 75% of all OSA affect the appendicular skeleton.
  • Most commonly affects distal radius; other common sites are distal femur, proximal tibia and proximal humerus.
  • Also affects axial skeleton and (rarely) soft tissues (extraskeletal OSA).
  • Appendicular OSA most common in large and giant breeds.
  • Signs: sudden onset lameness/metaphyseal swelling.
  • Treatment: surgery and chemotherapy.
  • Prognosis: poor long-term as metastatic spread common, if treated, good short-term prognosis.
    Print off the owner factsheet on Canine osteosarcoma Canine osteosarcoma to give to your client.



  • Unknown.

Predisposing factors

  • Size of animal: breeds weighing >35 kg are 60 times more at risk compared with breeds <10 kg.
  • Breeds 20-35 kg are 8 times more at risk compared with breeds <10 kg.


  • Affect metaphyseal areas of long bones. Most common site is distal radius (27%) followed by proximal humerus (27%), distal femur (14%), proximal (14%) or distal (7%) tibia. Thus the most common sites are 'away from the elbow, close to the stifle'.
  • Malignant tumor of bone cells.
  • Fast growing, rapidly metastasize to lungs Osteosarcoma: pulmonary metastases at post-mortem , spread to local lymph nodes is uncommon.
  • Radiographic evidence of metastasis to other bones in 6.4% of cases at time of diagnosis.
  • If treated with surgery and chemotherapy, 50% of cases develop bone metastases and 50%, pulmonary metastases Osteosarcoma: pulmonary metastases at post-mortem.


  • Untreated - most cases are euthanased withing weeks due to unremitting pain.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Hillers K R, Dernell W S, Lafferty M H, Withrow S J & Lana S E (2005) Incidence and prognostic importance of lymph node metastases in dogs with appendicular osteosarcoma: 228 cases (1986-2003). JAVMA 226 (8), 1364-1367 PubMed.
  • Fuchs B & Pritchard D J (2002) Etiology of osteosarcoma. Clin Orth Rel Res 397, 40-52 PubMed.
  • Dickerson M E, Page R L, LaDue T A et al (2001) Retrospective analysis of axial skeleton osteosarcoma in 22 large-breed dogs. JVIM 15 (2), 120-124 PubMed.
  • Langenbach A, McManus P M, Hendrick M J, Shofer F S & Sorenmo K U (2001) Sensitivity and specificity of methods of assessing the regional lymph nodes for evidence of metastasis in dogs and cats with solid tumours. JAVMA 218 (9), 1424-1428 PubMed.
  • Mehl M L, Withrow S J, Seguin B, Powers B E et al (2001) Spontaneous regression of osteosarcoma in four dogs. JAVMA 219 (5), 614-617 PubMed.
  • Blackwood L (1999) Bone tumours in small animals. In Practice 21 (1), 31-7 VetMedResource.
  • Ehrhart N et al (1998) Prognostic importance of alkaline phosphatase activity in serum from dogs with appendicular osteosarcoma - 75 cases (1990-1996). JAVMA 213 (7), 1002-1006 PubMed.
  • Bergman P J et al (1996) Amputation and carboplatin treatment of dogs with oesteosarcoma - 48 cases (1991 to 1993). J Vet Intern Med 10 (2), 76-81 PubMed.
  • McEntee M C et al (1993) Palliative radiotherapy for canine appendicular osteosarcoma. Vet Radiol 34 (5), 367-370 VetMedResource.
  • Ogilvie G K et al (1993) Evaluation of single-agent chemotherapy for treatment of clinically evident oesteosarcoma in dogs - 45 cases (1987-1991). JAVMA 202 (2), 304-306 PubMed.
  • Berg J et al (1992) Treatment of dogs with osteosarcoma by administration of cisplatin after amputation or limb-sparing surgery - 22 cases (1987-1990). JAVMA 200 (12), 2005-2008 PubMed.
  • Spodnick G J et al (1992) Prognosis for dogs with appendicular oesteosarcoma treated by amputation alone - 162 cases (1978-1988). JAVMA 200 (7), 995-999 PubMed.
  • Straw R C, Cook N L, LaRue S M, Withrow S J & Wrigley R H (1989) Radiographic bone surveys. JAVMA 195 (11), 1458 PubMed.
  • Powers B E, LaRue S M, Withrow S J, Straw R C & Richter S L (1988) Jamshidi needle biopsy for diagnosis of bone lesions in small animals. JAVMA 193 (2), 205-210 PubMed.
  • Carberry C A & Harvey H J (1987) Owner satisfaction with limb amputation in dogs and cats. JAAHA 23 (2), 227-232 VetMedResource.