Purpose: Electrochemotherapy (ECT) is the application of electric pulses to tumour tissue to render the cell membranes permeable to usually impermeant hydrophilic anti-cancer drugs, thereby enhancing cytotoxic effects. We sought to ascertain whether ECT can be an effective palliative treatment for cutaneous metastases of breast cancer.
Methods: This work reports data from the European Standard Operating Procedures for Electrochemotherapy trial (EudraCT Number: 2004-002183-18). In combination with systemic and/or intratumoural bleomycin, optimised electric pulses were delivered to locally recurrent or metastatic cutaneous breast cancer lesions. Follow-up continued until December 2014.
Results: Between February 2004 and December 2014, twenty-four patients were treated. All patients had received prior multimodal therapy. In total, the patient cohort had, or developed, 242 lesions. Two hundred and 36 lesions were treated, with 34 lost to follow-up. An objective response was seen in 161 of 202 lesions (79.7%), with a complete response observed in 130 (64.3%). Thirty-nine lesions (19.3%) did not respond, while 2 (1%) progressed following ECT. 17 (73.9%) patients received two or fewer treatments. A minimum of a partial response was seen in at least 50% of treated lesions in 18 of the 24 (75%) patients. Smaller lesions were more likely to have an objective response (Chi-square test for trend, p < 0.001).
Conclusions: Electrochemotherapy is an effective treatment for cutaneous breast cancer lesions that have proven refractory to standard therapies. As smaller lesions were found to be more responsive, we suggest that ECT should be considered as an early treatment modality, within multimodal treatment strategies.
Keywords: Bleomycin; Breast cancer; Cutaneous metastases; Electrochemotherapy; Locoregional recurrence.