Multicenter prospective trial of hypofractionated radiation treatment, toceranib, and prednisone for measurable canine mast cell tumors

J Vet Intern Med. 2012 Jan-Feb;26(1):135-41. doi: 10.1111/j.1939-1676.2011.00851.x. Epub 2011 Dec 19.

Abstract

Background: Mast cell tumors (MCT) are common cutaneous tumors in dogs and when not amenable to surgical excision can present a therapeutic challenge. New treatment protocols for unresectable MCT are needed.

Hypothesis: The combination of toceranib, prednisone, and hypofractionated radiation treatment (RT) will be well tolerated and efficacious.

Animals: Seventeen client-owned dogs with measurable MCT amenable to RT.

Methods: Prospective clinical trial. All dogs received prednisone, omeprazole, diphenhydramine, and toceranib. Toceranib was administered for 1 week before initiating RT, consisting of 24 Gy delivered in 3 or 4 fractions.

Results: On an intent-to-treat basis, the overall response rate was 76.4%, with 58.8% of dogs achieving a complete response and 17.6% a partial response. The median time to best response was 32 days, and the median progression-free interval was 316 days. The overall median survival time was not reached with a median follow-up of 374 days. The most common toxicoses were gastrointestinal and hepatic.

Conclusions and clinical importance: The combination of hypofractionated RT, toceranib, and prednisone was tolerated and efficacious in the majority of dogs. Response rates and durations were higher than those reported for toceranib as a single-agent treatment for MCT. This combination is a viable treatment option for unresectable MCT.

Publication types

  • Clinical Trial
  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use*
  • DNA, Neoplasm / chemistry
  • DNA, Neoplasm / genetics
  • Disease-Free Survival
  • Dog Diseases / drug therapy*
  • Dog Diseases / pathology
  • Dog Diseases / radiotherapy*
  • Dogs
  • Female
  • Indoles / administration & dosage
  • Kaplan-Meier Estimate
  • Male
  • Mast-Cell Sarcoma / drug therapy
  • Mast-Cell Sarcoma / pathology
  • Mast-Cell Sarcoma / radiotherapy
  • Mast-Cell Sarcoma / veterinary*
  • Polymerase Chain Reaction / veterinary
  • Prednisone / administration & dosage
  • Prospective Studies
  • Proto-Oncogene Proteins c-kit / genetics
  • Pyrroles / administration & dosage
  • Radiography
  • Skin Neoplasms / diagnostic imaging
  • Skin Neoplasms / drug therapy
  • Skin Neoplasms / pathology
  • Skin Neoplasms / veterinary*

Substances

  • DNA, Neoplasm
  • Indoles
  • Pyrroles
  • toceranib phosphate
  • Proto-Oncogene Proteins c-kit
  • Prednisone