Electrochemotherapy for Breast Cancer-Results From the INSPECT Database.

BACKGROUND: Cutaneous recurrence from breast cancer can pose a clinical challenge. It might be the only disease site, or could be part of disseminated disease, and often profoundly affects quality of life. Electrochemotherapy is a palliative treatment using electric pulses to locally permeabilize tumor cells and thereby significantly increase bleomycin cytotoxicity. Collaborating with the International Network for Sharing Practice on ElectroChemoTherapy (INSPECT), we consecutively and prospectively accrued data on patients treated with electrochemotherapy for cutaneous metastases from breast cancer. PATIENTS AND METHODS: Patients were treated with electrochemotherapy at 10 European centers. Under either local or general anaesthesia patients were treated with either local injection (1000 IU/mL intratumoral) or systemic infusion (15,000 IU/m2) of bleomycin. RESULTS: One hundred nineteen patients were included at 10 institutions in the INSPECT network. The primary location was the chest (89%), the median diameter of the cutaneous metastases was 25 mm. Ninety patients were available for response evaluation after 2 months. Complete response was observed in 45 patients (50%), partial response in 19 (21%), stable disease in 16 (18%), and progressive disease in 7 (8%). Three patients were not evaluable. Common side effects were ulceration, long-lasting hyperpigmentation, and low-grade pain. No serious adverse events were observed. CONCLUSION: Electrochemotherapy showed high response rates after a single treatment. Electrochemotherapy has few side effects and can be used as an adjunct to systemic therapies or as a solo treatment. We therefore recommend considering electrochemotherapy for patients with cutaneous metastases.

Electrochemotherapy - Supplementary Treatment for Loco-regional Metastasized Breast Carcinoma Administered to Concomitant Systemic Therapy.

BACKGROUND: Electrochemotherapy (ECT) is an established procedure for treating breast cancer loco-regional recurrences following surgical intervention and/or radiotherapy. Limited information is available on ECT application as a concomitant procedure to systemic therapy in recurrent breast cancer. The primary objective of this study was to determine if the application of ECT in close temporal relation to systemic chemotherapy could lead to increased local and/or systemic side effects. For this purpose we evaluated the safety of ECT as a supplemental local therapy to systemic therapy. ECT local and systemic toxicity and side effects were recorded and whether the anticipated local therapeutic effect of ECT would be influenced by the concomitant use of systemic therapies was investigated. PATIENTS AND METHODS: This is an observational study. Thirty three patients with loco-regional metastasized breast carcinoma were treated and observed over a period of three years with 46 ECT applications for local tumour control in addition to established systemic therapy. A specific timeline for ECT administration was not fixed up, but was generally performed one week before the following chemotherapy administration with the aim to avoid the so called nadir, this means the peak period with risk of neutropenia. RESULTS: Data was collected over a period of three years on a population of 33 metastatic patients. Fifteen patients, received neo-adjuvant therapy as part of their primary treatment, but still had an advanced stage tumour. Some patients received repeated ECT applications. Objective tumour response was observed in 90% of the treated patients. Patients showed no increased local toxicity, especially no higher dermal toxicity, e.g. formation of local necrosis. CONCLUSIONS: ECT proved to be an effective supplement to a cytotoxic systemic therapy, especially for high-risk patients who did not respond well to systemic therapy of loco-regional metastases, without creating any greater systemic or loco-regional toxicities.

The mutation Y1206S increases the affinity of the sulphonylurea receptor SUR2A for glibenclamide and enhances the effects of coexpression with Kir6.2.

1. ATP-sensitive K(+) channels (K(ATP) channels) are tetradimeric complexes of inwardly rectifying K(+) channels (Kir6.x) and sulphonylurea receptors (SURs). The SURs SUR2A (cardiac) and SUR2B (smooth muscle) differ only in the last 42 amino acids. In SUR2B, the mutation Y1206S, located at intracellular loop 8, increases the affinity for glibenclamide (GBC) about 10-fold. Here, we examined whether the mutation Y1206S in SUR2A had effects similar to those in SUR2B.2. GBC bound to SUR2A with K(D)=20 nM; the mutation increased affinity approximately 5 x. 3. In cells, coexpression of SUR2A with Kir6.2 increased the affinity for GBC approximately 3 x; with the mutant, the increase was 9 x. 4. The mutation did not affect the affinity of SUR2A for openers; coexpression with Kir6.2 reduced opener affinity of wild-type and mutant SUR2A by about 2 x. 5. The negative allosteric interaction between the opener, P1075, and GBC at wild-type and mutant SUR2A was markedly affected by the presence of MgATP and by coexpression with Kir6.2. 6. In inside-out patches, GBC inhibited the wild-type Kir6.2/SUR2A and 2B channels with IC(50) values of 27 nM; the mutation shifted the IC(50) values to approximately 1 nM. 7. The data show that the mutation Y1206S increased the affinity of SUR2A for GBC and modulated the effects of coexpression. Overall, the changes were similar to those observed with SUR2B(Y1206S), suggesting that the differences in the last 42 carboxy-terminal amino acids of SUR2A and 2B are of limited influence on the binding of GBC and P1075 to the SUR2 isoforms.