The Role of Electrochemotherapy in the Cutaneous and Subcutaneous Metastases from Breast Cancer: Analysis of Predictive Factors to treatment from an Italian Cohort of Patients

The treatment of cutaneous and subcutaneous localizations from breast cancer is still a therapeutic challenge. Electrochemotherapy (ECT) is one of the available options, and it is characterized by the association between the administration of a chemotherapic agent (Bleomycin) with the temporary raise of permeability of the cellular membrane induced by the local administration of electrical impulses (electroporation). ECT represents an effective therapy for loco-regional control of this disease. We decided to evaluate the response to this treatment in 55 patients who underwent ECT between January 2013 and March 2020 at our Institute. We performed a monocentric retrospective cohort study. ECT was administered following the ESOPE (European Standard Operative Procedure of Electrochemotherapy) guidelines, a set of criteria updated in 2018 by a panel of European experts on ECT who defined the indications for selecting the patients who can benefit from ECT treatment and the ones for technically performing the procedure. The responses were evaluated with the RECIST criteria (Response Evaluation Criteria in Solid Tumor). We found after 12 weeks of treatment a complete response (CR) in 64% of our patients. From the analysis divided for subgroups of covariates is emerged that lower BMI, reduced body surface and absence of previous radiation treatment could be predictive for a better complete response. This study suggests that the efficacy of the ECT treatment is related to the concurrent systemic therapies while administering ECT. The association between ECT and immunotherapy has offered better results than the association between ECT and chemotherapy (p-value = 0.0463). So, ECT is a valuable tool in the treatment of cutaneous and subcutaneous metastases from breast cancer and its efficacy in local control of these lesions improves when it is well planned in a therapeutic scenario. The treatment of cutaneous and subcutaneous localizations from breast cancer is still a therapeutic challenge. Electrochemotherapy (ECT) is one of the available options, and it is characterized by the association between the administration of a chemotherapic agent (Bleomycin) with the temporary raise of permeability of the cellular membrane induced by the local administration of electrical impulses (electroporation). ECT represents an effective therapy for loco-regional control of this disease. We decided to evaluate the response to this treatment in 55 patients who underwent ECT between January 2013 and March 2020 at our Institute. We performed a monocentric retrospective cohort study. ECT was administered following the ESOPE (European Standard Operative Procedure of Electrochemotherapy) guidelines, a set of criteria updated in 2018 by a panel of European experts on ECT who defined the indications for selecting the patients who can benefit from ECT treatment and the ones for technically performing the procedure. The responses were evaluated with the RECIST criteria (Response Evaluation Criteria in Solid Tumor). We found after 12 weeks of treatment a complete response (CR) in 64% of our patients. From the analysis divided for subgroups of covariates is emerged that lower BMI, reduced body surface and absence of previous radiation treatment could be predictive for a better complete response. This study suggests that the efficacy of the ECT treatment is related to the concurrent systemic therapies while administering ECT. The association between ECT and immunotherapy has offered better results than the association between ECT and chemotherapy (p-value = 0.0463). So, ECT is a valuable tool in the treatment of cutaneous and subcutaneous metastases from breast cancer and its efficacy in local control of these lesions improves when it is well planned in a therapeutic scenario.乳腺癌皮肤及皮下受累部位的治疗仍为临床治疗难题。电化学治疗（Electrochemotherapy, ECT）是现有可选治疗方案之一，其核心特征为将化疗药物博莱霉素（Bleomycin）的给药与局部给予电脉冲诱导的细胞膜通透性暂时性升高（电穿孔，Electroporation）相结合。ECT是实现该疾病局部区域控制的有效治疗手段。本研究纳入2013年1月至2020年3月于本机构接受ECT治疗的55例患者，旨在评估该治疗的应答效果。本研究为单中心回顾性队列研究。 ECT治疗严格遵循ESOPE（欧洲电化学治疗标准操作流程，European Standard Operative Procedure of Electrochemotherapy）指南：该指南由欧洲ECT专家小组于2018年更新，明确了可从ECT治疗中获益的患者遴选指征，以及该操作的技术实施规范。 疗效评估采用RECIST（实体瘤疗效评价标准，Response Evaluation Criteria in Solid Tumors）。治疗12周后，本队列中64%的患者达到完全缓解（Complete Response, CR）。 针对协变量亚组的分析显示，较低的身体质量指数（Body Mass Index, BMI）、较小的体表面积以及未接受过既往放射治疗，可能是更佳完全缓解的预测因素。 本研究提示，ECT治疗的疗效与治疗期间同步实施的全身治疗相关。ECT联合免疫治疗的效果优于ECT联合化疗（p值=0.0463）。因此，ECT是治疗乳腺癌皮肤及皮下转移灶的有效工具，若在治疗方案中进行合理规划，其局部病灶控制效果可进一步提升。 乳腺癌皮肤及皮下受累部位的治疗仍为临床治疗难题。电化学治疗（Electrochemotherapy, ECT）是现有可选治疗方案之一，其核心特征为将化疗药物博莱霉素（Bleomycin）的给药与局部给予电脉冲诱导的细胞膜通透性暂时性升高（电穿孔，Electroporation）相结合。ECT是实现该疾病局部区域控制的有效治疗手段。本研究纳入2013年1月至2020年3月于本机构接受ECT治疗的55例患者，旨在评估该治疗的应答效果。本研究为单中心回顾性队列研究。 ECT治疗严格遵循ESOPE（欧洲电化学治疗标准操作流程，European Standard Operative Procedure of Electrochemotherapy）指南：该指南由欧洲ECT专家小组于2018年更新，明确了可从ECT治疗中获益的患者遴选指征，以及该操作的技术实施规范。 疗效评估采用RECIST（实体瘤疗效评价标准，Response Evaluation Criteria in Solid Tumors）。治疗12周后，本队列中64%的患者达到完全缓解（Complete Response, CR）。 针对协变量亚组的分析显示，较低的身体质量指数（Body Mass Index, BMI）、较小的体表面积以及未接受过既往放射治疗，可能是更佳完全缓解的预测因素。 本研究提示，ECT治疗的疗效与治疗期间同步实施的全身治疗相关。ECT联合免疫治疗的效果优于ECT联合化疗（p值=0.0463）。因此，ECT是治疗乳腺癌皮肤及皮下转移灶的有效工具，若在治疗方案中进行合理规划，其局部病灶控制效果可进一步提升。