Electrochemotherapy Fact Sheet

What is electrochemotherapy?

Electrochemotherapy treatment combines the use of a chemotherapeutic agent (usually bleomycin) with the application of electric pulses to the tumour. The chemical and physical characteristics of bleomycin mean it is poorly absorbed by cancer cells under normal conditions. The application of electric pulses causes alterations in the cell membrane that allow bleomycin to better penetrate and remain inside the cell. This allows for high concentrations of the chemotherapeutic agent to reach the tumour, while minimising exposure to the rest of the body, thus minimising side effects.

The same equipment can be used to perform gene transfer to administer immunotherapy (still largely limited to research studies).

In which cases can we use electrochemotherapy?

Electrochemotherapy treatment can be used on virtually any cutaneous or oral tumour, either as first-line treatment when surgery is not an option or as post-operative (adjuvant) treatment when complete tumour removal cannot be achieved with surgery alone.

As treatment causes few side effects, electrochemotherapy can be administered to more sensitive areas of the body such as the footpads, nasal planum and perianal area.

Despite electrochemotherapy being a relatively new treatment, there are several studies reporting its efficacy and tolerability in various tumours in dogs and cats, including mast cell tumours, oral and cutaneous melanoma, oral and cutaneous squamous cell carcinoma, plasma cell tumours, soft tissue sarcomas, perianal adenomas and carcinomas of the anal sac.

What does electrochemotherapy involve?

Treatment can vary depending on the type of tumour, its size, location and the presence of comorbidities. Electrochemotherapy can be administered intraoperatively or postoperatively. Intraoperative treatment is performed at the time of tumour removal, to treat the tumour bed and reduce the risk of tumour recurrence for invasive tumours such as soft tissue sarcoma and infiltrative mast cell tumours.

More commonly, electrochemotherapy treatment is performed following surgery on the residual scar (or on the tumour itself, if the tumour is not amenable to surgery). In these cases, treatment is performed under general anaesthesia. The patient is positioned appropriately, the treatment area is shaved, and chemotherapy is administered either intravenously or directly into the tumour.

After waiting 10 minutes for the chemotherapy drug to penetrate the cells, needles delivering an electric pulse are applied over the tumour area and surgical margins. The number of applications and the depth of these needles depends on the tumour size and location. Following the electrochemotherapy treatment, the patient is kept for a few hours to recover from the anaesthesia and can go home.

In most cases two treatments (administered 2 to 4 weeks apart) are recommended. However, a single treatment can be considered in some cases. Equally, there are certain cases that require more than two treatments.

What we should expect after electrochemotherapy?

The majority of dogs and cats undergoing electrochemotherapy treatment do not require hospitalisation and can go home with a few hours. Post-treatment management depends on the type of tumour treated. Most cases only require some topical ointments and 3 days of anti-inflammatory medications.

Most patients will completely recover in 2 to 4 weeks. During this time, the area might undergo some changes compatible with the regression of the tumour. We suggest wearing a buster collar to prevent the dog or cat from self-traumatising the area (regardless of whether the animal appears bothered by the area or not).

If you have a patient that you think may benefit from electrochemotherapy, or any general enquiries do not hesitate to contact us at [email protected].