Electrochemotherapy for Mammary Tumour in Dogs

Background: Mammary neoplasms are the most common tumours in the bitch. Even though surgery remained the treatment of choice for mammary gland tumours except those with inflammatory carcinomas or distant metastasis; it did not seem to reduce the chances of recurrence in case of malignancy in dogs. Other alternatives to surgery are chemotherapy, immunotherapy, radiation therapy, hormonal therapy etc. The major disadvantage of chemotherapeutic agents was the lack of selectivity for tumour cells. To overcome this problem, electrochemotherapy could be used as a single or as an adjuvant therapy to surgery which could be used for treatment of inoperable tumours. Cisplatin and bleomycin are the two chemotherapeutic agents used in veterinary oncology for electrochemotherapy. This study was carried out on clinical cases of mammary tumours to study and compare the efficacies of electrochemotherapy using Cisplatin and bleomycin Methods: The research was carried out on clinical cases of canine mammary tumour presented to the Small Animal Surgical Out-Patient Unit of Madras Veterinary College Teaching Hospital for a period of one year from September 2018 to May 2021. Routine Clinical, Haematological, Biochemical and Radiographic evaluations were performed. Twelve dogs with mammary tumours, with a single solitary lump were selected for the study irrespective of the age, breed and location. Group I Cases were treated by electrotherapy with cisplastin and Group II were treated by electrotherapy with bleomycin intralesionally following which surgical excision was performed. Result: Most cases in the cisplatin group produced partial response (3/6) according to the response evaluation criteria, whereas most cases in the bleomycin group produced complete response (100% regression). Bleomycin was comparatively more efficient (1.7 times) than cisplatin in electrochemotherapy for mammary tumours. The time under anaesthesia was low which makes this procedure a suitable alternative to geriatric dogs that cannot be anaesthetised for a longer duration for surgery.