Soft tissue sarcoma in dogs: A treatment review and a novel approach using electrochemotherapy in a case series

Abstract

Canine soft tissue sarcomas (STSs) are locally invasive mesenchymal neoplasms. Electrochemotherapy (ECT) is an antitumour local ablative treatment that uses electric pulses to enhance the intracellular delivery of cytotoxic drugs. The aim of this retrospective study was to review the current treatment for STSs and to evaluate the efficacy and safety of ECT with bleomycin in canine STSs. Fifty‐two dogs with 54 STSs were included. Three groups were arranged: (a) ECT alone, (b) intra‐operative ECT and (c) adjuvant ECT. Signalment, tumour size, location, histological grade and margins and ECT parameters were collected. Recurrence rate (RR) and disease‐free interval (DFI) were calculated. Treatment toxicity was assessed using a 6‐point scale. STSs were mostly located on limbs (77.8%). Median tumour size was 4.3 cm (range 0.4‐17.0 cm). Most STSs were grade I (47.7%) and II (50.0%), and histological margins were incomplete in 94.5% of cases. Two complete remissions, one partial remission and one stable disease were recorded in group 1. Group 2 and 3 were similar for tumour location, size and grade, histological margins, treatment toxicity, pulse frequency and voltage. Moreover, RR and DFI were similar between group 2 and 3 (23% and 25%, 81.5 and 243 days, respectively). Local toxicity post ECT was mild (score ≤ 2) in 66.7% of cases. Higher toxicity score was associated with higher pulse voltage (1200 vs 1000 V/cm) (P = 0.0473). ECT coupled with bleomycin resulted safe and efficient in tumour local control and should be considered as an option for treatment of canine STSs.

Electroporation-Based Treatments in Small Animal Veterinary Oral and Maxillofacial Oncology

“…Generally, ECT/GET treatments are well-tolerated, with most of the dogs in all studies maintaining their normal habits and routines ( 56 , 64 , 65 , 70 , 71 , 85 , 87 ). Conversely, Torrigiani et al ( 34 ) reported higher local treatment toxicity if a higher amplitude to electric distance ratio (1,200 vs. 1,000 V/cm) was used with type II needle electrodes. However, the possible post-treatment complications can be considered much less severe than those of surgery for oral tumors ( 79 ) or radiotherapy ( 89 , 90 ).…”

“…Torrigiani et al ( 34 ) also treated non-metastatic soft tissue sarcomas in dogs with ECT. Of 52 dogs with 54 spontaneous soft tissue sarcomas, five had a (non-oral) tumor on the head without further specification of the exact location.…”

“…In addition, the group compared the treatment outcomes when using two different pulse generators with different ECT parameters. They found no differences in outcomes when comparing the groups treated with different pulse generators, but they observed a higher treatment toxicity score in the group treated with a higher amplitude to electric distance ratio (1,200 vs. 1,000 V/cm) ( 34 ).…”

Recent Advances in Electrochemotherapy

“…The recurrence rate in groups that were treated with electrochemotherapy during or after surgery was similar (23% and 25%). 94 In another study, in addition to an intravenous administration of bleomycin, the tumor bed was also infiltrated with cisplatin. This combination was very effective, 26 of 30 dogs were without evidence of recurrence, and the median estimated disease-free interval was 857 days.…”

“…The results of electrochemotherapy treatment of two large cohorts of dogs with soft tissue sarcoma were recently published. In a study by Torrigiani et al, 94 52 dogs with 54 soft tissue sarcomas were treated either with electrochemotherapy with bleomycin alone, during open surgery, or with electrochemotherapy as an adjuvant to surgery. The recurrence rate in groups that were treated with electrochemotherapy during or after surgery was similar (23% and 25%).…”