Adjuvant electrochemotherapy for the treatment of incompletely resected canine mast cell tumors

Background: Electrochemotherapy (ECT) is a novel anticancer therapy that combines the delivery of trains of appropriate waveforms with the local administration of chemotherapy agents. The purpose of this investigation was to assess the adjuvant potentials of ECT for the treatment of incompletely excised mast cell tumors (MCT). Materials and Methods: Twenty-eight privately-owned dogs with incompletely removed MCT were treated with intralesional bleomycin (1.5 IU/cm2) followed by the application of trains of biphasic pulses (8 pulses, 1300 V/cm, 50 + 50 μs duration, 1 Hz frequency). Results: The overall response rate was 85% with a mean estimated time to recurrence of 52.76±6.5 months (range: 39.99 to 65.54 months, 95% CI). At the time of writing this report, the median survival time was not reached. Three dogs died of metastatic disease that they developed at the same time of local recurrence, one developed multiple cutaneous nodules at different locations and one with recurrence was re-treated and is currently disease-free after 22 months. No major local or systemic toxicities were noted for the duration of the study. Conclusion: ECT is a safe and effective therapy for incompletely excised MCTs in companion animals. Its ease of administration, lack of toxicities and low cost make it an attractive alternative to standard treatments and warrants further investigation.