Abstract P5-22-23: Electrochemotherapy : A new local therapy for cutaneous metastases of breast cancer

Abstract

Abstract Background : Electrochemotherapy (ECT) is a new local therapy combining the administration of an intravenous chemotherapy (bleomycin) followed by the direct application of electric pulses by an electrode to the treated areas. Electric pulses transiently permeabilize the membrane of the tumor cell ( electroporation), improving intracellular diffusion of a poorly permeant chemotherapeutic agent, ithereby ncreasing its cytotoxicity and decreasing systemic toxicity. ECT can be offered to patients with cutaneous or subutaneous metastases of breast cancer who are no longer suitable for extensive surgery or radiotherapy ( e.g. due to past irradiation of the breast or chest wall). ECT 's applications are palliative. It is -, delivered with the aim of local control of the tumor, relief of symptoms associated with cutaneous recurrence -(ulceration, bleeding, pain),i and mproving patients'quality of life. The aim of this study is to demonstrate that ECT has a high efficacity and a low toxicity profile making it an interesting alternative to conventional therapies. Material and methods : our study is a retrospective study (approved by our local ethics committee) which included 8 patients between June 2013 and June 2016. The patients had histologically proven cutaneous and or subcutaneous metastases of their breast cancer, without any sign of lymphangitis. All the tumors expressed ER and /or PgR and 2 of them were HER2 positive tumors. The patients received a single or multiple courses of ECT ; the outcomes were clinical response, toxicity, local and distant recurrence. The two patients whose tumors expressed HER2, also had synchronous controlateral axillary nodal metastases. They underwent axillary dissection performed during ECT course. Among the six other patients, no other metastases than cutaneous lesions were observed. Results : The 8 included patients had already received chest wall irradiation for the treatment of their primary breast cancer. A total of 37 nodules were treated (mean : 4.5 per patient), whose mean size was 17mm (10-34mm). Six patients(75%) had a complete response after a single course of ECT. Two patients exhibited a partial response and underwent a second course of ECT at 6 months. The two patients with Her2 positive tumors received taxane-based chemotherapy and anti HER2 agents. All the patients were also given endocrine therapy. After a median follow up of 26 months (11-47 months), no patient had a local cutaneous recurrence. Overall survival rate was 75% : 2 patients died following progression of systemic disease (pulmonary and hepatic metastases). No complications due to toxicity were observed. Discussion and conclusion :In selected patients with ( cutaneous and subcutaneous metastases of breast cancer with no sign of lymphangitis), ECT offers a very good rate of clinical response and a durable control of metastases. This innovative technique has the advantage of being minimally –invasive and well –tolerated. Citation Format: Berliere M, Raguzzi E, Bernard M, Gerday A, Coyette M, Piette P, Duhoux F, Lengele B. Electrochemotherapy : A new local therapy for cutaneous metastases of breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-22-23.