Efficacy and side effects of radiation therapy in comparison with radiation therapy and temozolomide in the treatment of measurable canine malignant melanoma

Vet Comp Oncol. 2016 Dec;14(4):e146-e157. doi: 10.1111/vco.12122. Epub 2014 Nov 10.

Abstract

Prognosis for unresectable canine malignant melanoma (MM) is typically poor, and therapeutic approaches remain largely palliative. A bi-institutional trial was conducted to compare efficacy and safety of radiation therapy (RT) and RT with post-radiation temozolomide in dogs with chemotherapy-naïve, measurable MM. RT consisted of 5 × 6 Gy fractions over 2.5 weeks. Dogs whose owners wished to pursue chemotherapy received adjuvant oral temozolomide (60 mg m-2 for 5 days every 28 days). Fifteen dogs were treated with RT only (Group 1) and 12 dogs subsequently received temozolomide (Group 2). Overall response rate was similar between Group 1 (86.7%) and Group 2 (81.1%). Median time to progression (TTP) was significantly longer in Group 2 (205 days) compared to Group 1 (110 days; p = 0.046). Survival time was not significantly different between groups. Both treatments were well tolerated. Post-radiation temozolomide has a good safety profile, and may improve TTP in MM when compared to coarse fractionated RT.

Keywords: dog; malignant melanoma; radiation therapy; temozolomide.

Publication types

  • Controlled Clinical Trial

MeSH terms

  • Animals
  • Antineoplastic Agents, Alkylating / administration & dosage
  • Antineoplastic Agents, Alkylating / adverse effects
  • Antineoplastic Agents, Alkylating / therapeutic use
  • Combined Modality Therapy
  • Dacarbazine / administration & dosage
  • Dacarbazine / adverse effects
  • Dacarbazine / analogs & derivatives*
  • Dacarbazine / therapeutic use
  • Dog Diseases / therapy*
  • Dogs
  • Melanoma / therapy
  • Melanoma / veterinary*
  • Radiotherapy / veterinary*
  • Temozolomide

Substances

  • Antineoplastic Agents, Alkylating
  • Dacarbazine
  • Temozolomide