Canis ISSN: 2398-2942

Osteosarcoma: chemotherapy protocols

Contributor(s): Jane Dobson, Corey Saba

Protocol 1: Single-agent carboplatin

  • Week 1: CBC. Carboplatin Carboplatin 300 mg/m2 IV.
  • Week 2: No chemotherapy. Recheck CBC.
  • Week 3: No chemotherapy. Recheck CBC.
  • Week 4: Recheck CBC. Carboplatin 300 mg/m2 IV.
  • Week 7: Recheck CBC. Carboplatin 300 mg/m2 IV.
  • Week 10: Recheck CBC. Carboplatin 300 mg/m2 IV.

Important considerations

Carboplatin is a potent cytotoxic drug and should only be administered by trained personnel.

  • For dogs weighing <15 kg, reduce carboplatin dose to 250-270 mg/m2.
  • Myelosuppression, specifically neutropenia and/or thrombocytopenia, is the most common side effects of carboplatin. Neutrophil nadirs are variable with this drug and can occur at roughly 7, 14, and/or 21 days post-treatment. Gastrointestinal effects, such as anorexia and/or vomiting, may occur but are less common.
  • Perform a complete blood count (CBC Hematology: complete blood count (CBC) ) with platelet count Hematology: platelet count within 48 hours prior to every dose of chemotherapy. Delay chemotherapy by 3-7 days and recheck CBC if neutrophils <2000 cells/uL and/or if platelets <75,000 cells/uL.
  • Perform a CBC with platelet count 7 and 14 days after the first dose of carboplatin to assess degree of myelosuppression. Consider prophylactic antibiotics in afebrile, apparently healthy patients with neutrophil counts <1000 cells/uL. Consider hospitalization and treatment for sepsis (IV fluids and broad spectrum antibiotics) in febrile and/or sick patients with neutropenias. Once the nadir(s) has been established, 7 and 14 day post-chemotherapy CBCs are unnecessary unless the patient becomes ill and/or if dose reductions are required (see below).
  • Reduce carboplatin dose by 25% in patients experiencing significant myelosuppression, GI toxicity, and/or in those requiring hospitalization due to toxicity. Following dose reduction, recheck CBC with platelet count 7 and 14 days after treatment.
  • Recheck thoracic radiographs prior to 3rd or 4th treatment. If pulmonary metastasis is evident, discontinue carboplatin. Otherwise, continue treatments for 4-6 doses total.

Protocol 2: Single-agent doxorubicin

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Protocol 3: Alternating carboplatin/doxorubicin

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Legal and safety precautions

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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Phillips B, Powers B E, Dernell W S et al (2009) Use of single-agent carboplatin as adjuvant or neoadjuvant therapy in conjunction with amputation for appendicular osteosarcoma in dogs. J Am Anim Hosp Assoc 45 (1), 33-38 PubMed.
  • Bacon N J, Ehrhart N P, Dernell W S et al (2008) Use of alternating administration of carboplatin and doxorubicin in dogs with microscopic metastases after amputation for appendicular osteosarcoma: 50 cases (1999-2006). J Am Vet Med Assoc 232 (10), 1504-1510 PubMed.
  • Kent M S, Strom A, London C A et al (2004) Alternating carboplatin and doxorubicin as adjunctive chemotherapy to amputation or limb-sparing surgery in the treatment of appendicular osteosarcoma in dogs. J Vet Intern Med 18 (4), 540-544 PubMed.
  • Bergman P J, MacEwen E G, Kurzman I D et al (1996) Amputation and carboplatin for treatment of dogs with osteosarcoma: 48 cases (1991 to 1993). J Vet Intern Med 10 (2), 76-81 PubMed.
  • Berg J, Weinstein M J, Springfield D S et al (1995) Results of surgery and doxorubicin chemotherapy in dogs with osteosarcoma. J Am Vet Med Assoc 206 (10), 1555-1560 PubMed.