276P - Electrochemotherapy for breast cancer - results from the INSPECT database

Abstract

Cutaneous recurrence from breast cancer can pose a clinical challenge. It may be the only disease site, or be part of disseminated disease, and often profoundly impacts quality of life. Electrochemotherapy is a palliative treatment for cutaneous metastases. Using electric pulses to locally permeabilize tumor cells, bleomycin cytotoxicity is significantly increased. Collaborating in the International Network for sharing Practice on ElectroChemoTherapy (INSPECT), we consecutively and prospectively accrued data on patients treated with electrochemotherapy for skin metastases of breast cancer. Patients with cutaneous metastases were treated with electrochemotherapy at 10 European centers. Treatment data and results were entered into the INSPECT database. Patients were treated with either local injection (1000 IU/ml intratumoral injection) or systemic infusion (15.000 IU/m2) of bleomycin, and under either local or general anesthesia, depending on tumor size. Pulse sequences (8 pulses of 0.1 ms) were sequentially applied to the tumor area, using an electroporation system with needle or plate electrodes (IGEA, Italy). 104 patients were included. Median age was 65 years. Patients had previous received chemotherapy (87%), radiotherapy (83%), endocrine therapy (46%) and HER2 targeted therapy (20%). Primary location was the chest (87%), median diameter of the cutaneous metastases being 26 mm (range 1 mm to 550 mm). 75 patients were available for response evaluation after 2 months. Complete response was observed in 38 (51%) patients, partial response in 13 (17%), stable disease in 14 (19%), and progressive disease in 5 (9%), 3 patients were not evaluable. Common side effects were ulceration, long lasting hyperpigmentation, and slight increase in pain. No serious adverse events were observed. Electrochemotherapy showed high response rates, particularly in smaller metastases. Electrochemotherapy has high response rates seen after a single treatment, with few side effects and can be used as an adjunct to systemic therapies as well as a sole treatment. We therefore highly recommend to consider electrochemotherapy for patients with cutaneous metastases, where radiotherapy and surgery is not an option.