ISSN 2398-2969      



Synonym(s): OSA


  • Definition: malignant mesenchymal tumor of primitive bone cells. 
  • 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 ('away from the elbow, close to the stifle').
  • Also affects axial skeleton and (rarely) soft tissues (extraskeletal OSA).
  • Appendicular OSA most common in large and giant breeds (95% for dogs weighing more than 40 kg).
  • 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.
  • A hereditary basis has been suspected based on increased prevalence in related families and genetic loci have been identified to contribute to heritable OSA in Greyhounds, Rottweilers, and Irish Wolfhounds.   
  • Mutation within tumor suppressor genes (p53, retinoblastoma, PTEN) are genetic factors suspected to cause OSA.

Predisposing factors


  • Size of animal: breeds weighing >35 kg are 60 times more at risk compared with breeds <10 kg. There is speculation that because OSA is more common in heavy dogs, it could be induced by multiple minor trauma in the physeal region.
  • Breeds 20-35 kg are 8 times more at risk compared with breeds <10 kg.
  • OSA has been associated with metallic implants (for fracture repair or TPLO/TTA), chronic osteomyelitis, radiotherapy (incidence of less than 5% for the latter).


  • Malignant tumor of bone cells.
  • Fast growing, rapidly metastasize to lungs (hematogenous route) 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.
  • Skip metastases (ie synchronous regional bone metastases) have been reported in dogs.
  • If treated with surgery and chemotherapy, 50% of cases develop bone metastases and 50%, pulmonary metastases Osteosarcoma: pulmonary metastases at post-mortem.
  • OSA has been shown to secrete nociceptive ligands potentially generating pain.


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


This article is available in full to registered subscribers

Sign up now to start a free trial to access all Vetlexicon articles, images, sounds and videos, or Login


This article is available in full to registered subscribers

Sign up now to start a free trial to access all Vetlexicon articles, images, sounds and videos, or Login


This article is available in full to registered subscribers

Sign up now to start a free trial to access all Vetlexicon articles, images, sounds and videos, or Login

Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Edmunds G L, Smalley M J, Beck S, Errington R J, Gould S et al (2021) Dog breeds and body conformations with predisposition to osteosarcoma in the UK: a case-control study. Canine Med Genet 8, 2 PubMed.
  • Al-Khan A A, Nimmo J S, Tayebi M, Ryan S D, Simcock O (2020) Parathyroid hormone receptor 1 (PTHR1) is a prognostic indicator in canine osteosarcoma. Sci Rep 10, 1564 PubMed.
  • Hoddinott K, Oblak M L, Wood G A, Boston S, Mutsaers A J (2020) Effect of timing of bisphosphonate administration on canine osteosarcoma cells undergoing radiation therapy. Can J Vet Res 84(3), 225-229 PubMed
  • Sharma S, Boston S E, Riddle D, Isakow K (2020) Osteosarcoma of the proximal tibia in a dog 6 years after tibial tuberosity advancement. Can Vet J 61(9), 946-950 PubMed
  • Tremolada G, Thamm DH, Milovancev M, Seguin B (2020) Biological behaviour of primary osteosarcoma of the digits, metacarpal and metatarsal bones in dogs. Vet Comp Oncol Sept 2020 PubMed.
  • Laver T , London C A, Vail D M, Biller B J, Coy J, Thamm D H (2018) Prospective evaluation of toceranib phosphate in metastatic canine osteosarcoma. Vet Comp Oncol 16(1), E23-E29 PubMed.
  • Kim C, Matsuyama A, Mutsaers A J, Woods J P (2017) Retrospective evaluation of toceranib (Palladia) treatment for canine metastatic appendicular osteosarcoma. Can Vet J 58(10),1059-1064 PubMed
  • Sabattini S, Renzi A, Buracco  P, Defourny S, Garnier‐Moiroux M (2017) Comparative Assessment of the Accuracy of Cytological and Histologic Biopsies in the Diagnosis of Canine Bone Lesions. J Vet Intern Med 31(3), 864-871 PubMed
  • Skorupski K A ,Uhl J M , Szivek A, Allstadt Frazier S D, Rebhun R B, Rodriguez Jr C O (2016) Carboplatin versus alternating carboplatin and doxorubicin for the adjuvant treatment of canine appendicular osteosarcoma: a randomized, phase III trial. Vet Comp Oncol 14(1), 81-87 PubMed
  • London C A, Gardner H L,Mathie T, Stingle N, Portela R et al (2015) Impact of Toceranib/Piroxicam/Cyclophosphamide Maintenance Therapy on Outcome of Dogs with Appendicular Osteosarcoma following Amputation and Carboplatin Chemotherapy: A Multi-Institutional Study. PLoS One 10(4), e0124889 PubMed.
  • Shor S, Fadl-Alla B A, Pondenis H C, Zhang X, Wycislo K L (2015) Expression of nociceptive ligands in canine osteosarcoma. J Vet Intern Med 29(1), 268-275 PubMed
  • Amsellem P M, Selmic L E, Wypij J M, Bacon N J, Culp W T N et al (2014) Appendicular osteosarcoma in small-breed dogs: 51 cases (1986-2011). J Am Vet Med Assoc 245(2), 203-210 PubMed.
  • Bracha S, Walshaw R, Danton T, Holland S, Ruaux C, Obradovich J (2014) Evaluation of toxicities from combined metronomic and maximal-tolerated dose chemotherapy in dogs with osteosarcoma. J Small Anim Pract 55(7), 369-374 PubMed
  • Culp W T N, Olea-Popelka F, Sefton J, Aldridge C F, Withrow S J (2014) Evaluation of outcome and prognostic factors for dogs living greater than one year after diagnosis of osteosarcoma: 90 cases (1997-2008). J Am Vet Med Assoc 245(10), 1141-1146 PubMed.
  • Sartor A J, Ryan S D, Sellmeyer T, Withrow S J, Selmic L E (2014) Bi-institutional retrospective cohort study evaluating the incidence of osteosarcoma following tibial plateau levelling osteotomy (2000-2009). Vet Comp Orthop Traumatol 27(5), 339-345 PubMed
  • Selmic L E, Lafferty M H, Kamstock D A, Garner A, Ehrhart N P et al (2014) Outcome and prognostic factors for osteosarcoma of the maxilla, mandible, or calvarium in dogs: 183 cases (1986-2012). J Am Vet Med Assoc 245(8), 930-938 PubMed.
  • Selmic L E, Ryan S D, Boston S E, Liptak J M, Culp W T N et al (2014) Osteosarcoma following tibial plateau leveling osteotomy in dogs: 29 cases (1997-2011). J Am Vet Med Assoc 244(9), 1053-1059 PubMed.  
  • Selmic L E, Burton J H, Thamm D H, Withrow S J, Lana S E (2014) Comparison of carboplatin and doxorubicin-based chemotherapy protocols in 470 d5ogs after amputation for treatment of appendicular osteosarcoma. J Vet Intern Med 28(2), 554-63 PubMed.
  • Neihaus S A, Locke J E, Barger A M, Borst LB, Goring R L (2011) A Novel Method of Core Aspirate Cytology Compared to Fine-Needle Aspiration for Diagnosing Canine Osteosarcoma.  
    J Am Anim Hosp Assoc 47(5), 317-323 PubMed
  • 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.

Other Sources of Information

  • Ehrart N, Christensen N I, Fan T H (2020) Cancer chemotherapy. In: Small Animal Clinical Oncology. 6th edn. Eds Withrow & MacEwen’s. Elsevier Saunders, St. Louis. pp 524-550. 

Related Images



Want more related items, why not
contact us

Can’t find what you’re looking for?

We have an ever growing content library on Vetlexicon so if you ever find we haven't covered something that you need please fill in the form below and let us know!


To show you are not a Bot please can you enter the number showing adjacent to this field