Felis ISSN 2398-2950

Mast cell tumor: chemotherapy protocols

Contributor(s): Jane Dobson, Corey Saba

Protocol 1

**Please note:  Protocols are not listed in order of preference or efficacy.

Vinblastine/prednisone protocol

  • Week 1Vinblastine Vinblastine 2-2.5 mg/m2 IV. Prednisone Prednisolone 1 mg/kg PO SID.
  • Week 2Vinblastine2-2.5 mg/m2 IV. Prednisone1 mg/kg PO SID.
  • Week 3Vinblastine2-2.5 mg/m2 IV. Prednisone1 mg/kg PO SID.
  • Week 4Vinblastine2-2.5 mg/m2 IV.  Prednisone1 mg/kg PO SID.
  • Week 5:  No chemotherapy. Prednisone1 mg/kg PO SID.
  • Week 6Vinblastine2-2.5 mg/m2 IV. Prednisone1 mg/kg PO SID.
  • Week 7:  No chemotherapy. Prednisone1 mg/kg PO SID.
  • Week 8Vinblastine2-2.5 mg/m2 IV.
  • Week 9:  No chemotherapy. Prednisone1 mg/kg PO SID.
  • Week 10Vinblastine2-2.5 mg/m2 IV.
  • Week 11:  No chemotherapy. Prednisone1 mg/kg PO SID.
  • Week 12Vinblastine2-2.5 mg/m2 IV. Prednisone1 mg/kg PO SID.

Important considerations

  • Although use of this protocol has not been reported in cats in the veterinary literature, anecdotally it has been used in patients with non-resectable MCT Mastocytoma, metastatic MCT, anaplastic MCT, and/or visceral MCT.
  • For cats weighing <15 kg, use lower end of vinblastine dose (2.0 mg/m2).
  • Myelosuppression and gastrointestinal toxicity (eg inappetence, vomiting, and/or diarrhea) are possible toxicities of vinblastine.
  • Extravasation injury is also an important toxicity. Vinblastine should be administered through a clean stick catheter and given as a bolus.  Careful monitoring of the patient is advised during administration to ensure the catheter remains in place. 
  • A complete blood count (CBC Hematology: complete blood count (CBC)) with platelet count Hematology: platelet count must be performed within 48 hours prior to chemotherapy administration. Ideally this should be done the day of chemotherapy administration. Delay chemotherapy by 3-7 days and then recheck CBC if:
    • Neutrophil count < 2000 cells/µl.
    • Platelet count < 75,000 cells/µl.
    • Patient is exhibiting GI signs secondary to previous chemotherapy.
  • Reduce vinblastine dose by 25% in patients experiencing significant myelosuppression, GI toxicity and/or those requiring treatment delays during weekly administration. 
  • Taper and discontinue prednisone after the final vinblastine treatment.
  • Restage Neoplasia: TNM staging patients prior to final vinblastine treatment.

Protocol 2

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Legal and safety precautions

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Rassnick K M, Williams L E, Kristal O et al (2008) Lomustine for treatment of mast cell tumors in cats: 38 cases (1999-2005). J Am Vet Med Assoc 232 (8), 1200-1205 PubMed.
  • Graham-Mize C A,  Rosser E  J (2004) Bioavailability and activity of
    prednisone and prednisolone in the feline patient.
    Vet Dermatol 15 (Suppl 1), 9-10.
  • Fan T M, Kitchell B E, Dhaliwal R S et al (2002) Hematological toxicity and therapeutic efficacy of lomustine in 20 tumor-bearing cats: critical assessment of a practical dosing regimen. J Am Anim Hosp Assoc 38 (4), 357-363 PubMed.
  • Rassnick K M, Gieger T L, Williams L E et al (2001) Phase I evaluation of CCNU (lomustine) in tumor-bearing cats. J Vet Intern Med 15 (3), 196-199 PubMed.
  • Rassnick K M, Moore A S, Williams L E et al (1999) Treatment of mast cell tumors with CCNU (lomustine). J Vet Intern Med 13 (6), 601-605 PubMed.


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