Electrochemotherapy is a combined use of certain chemotherapeutic drugs and electric pulses applied to the treated tumour nodule. Local application of electric pulses to the tumour increases drug delivery into cells, specifically at the site of electric pulse application. Drug uptake by delivery of electric pulses is increased for only those chemotherapeutic drugs whose transport through the plasma membrane is impeded. Among many drugs that have been tested so far, bleomycin and cisplatin found their way from preclinical testing to clinical use. Clinical data collected within a number of clinical studies indicate that approximately 80% of the treated cutaneous and subcutaneous tumour nodules of different malignancies are in an objective response, from these, approximately 70% in complete response after a single application of electrochemotherapy. Usually only one treatment is needed, however, electrochemotherapy can be repeated several times every few weeks with equal effectiveness each time. The treatment results in an effective eradication of the treated nodules, with a good cosmetic effect without tissue scarring.
Increase in cytotoxicity of bleomycin by exposure of cells to electroporative electric pulses was first described by Okino M and Mir LM 3,4. Thereafter electrochemotherapy was demonstrated to be effective also for cisplatin 5. Extensive preclinical data were collected on in vitro and in vivo tumour models in the following years. Treatment effectiveness was determined in relation to drug dosage, route of its administration, timing of drug injection and application of electric pulses, intensity of the electric field, coverage with sufficiently high electric field (E), and appropriate selection of electrodes and positioning with respect to the tumour 1,6,7,8. Furthermore, mechanisms underlying the effectiveness of electrochemotherapy were elaborated, demonstrating that, besides direct effect of electrochemotherapy to tumour cells, vascular disrupting effect and immune response are involved 1,6,9. All of these collected data enabled translation of electrochemotherapy into the clinics.
The first clinical trials demonstrated effectiveness of electrochemotherapy on head and neck and melanoma tumour nodules 10. Later on, its effectiveness was demonstrated on other tumour types, such as basal cell carcinoma of the skin, cutaneous metastases of melanoma, mammary tumours, hypernephroma and Kaposi's sarcoma. There are several reports evaluating collectively all clinical data published on electrochemotherapy with bleomycin and cisplatin 11-15. Overall, the response rate of the treated tumours was approximately 80% objective responses and approximately 70% complete responses 15,16. The effectiveness can be even higher by repetitive treatment 17.
All of these clinical data have enabled electrochemotherapy to be adopted in some European countries as standard treatment, with palliative intent, on various tumours. The future of this treatment is to introduce electrochemotherapy in treatment of internal tumours and metastases, and in combined treatment, either with gene therapy or radiation therapy. These attempts are already under way.
1. Mir, L.M. Bases and rationale of the electrochemotherapy. EJC Suppl. 4, 38–44 (2006).
2. Mir, L.M., Gehl, J., Sersa, G., Collins, C.G., Garbay, J.R., Billard, V., Geertsen, P., Rudolf, Z., O’Sullivan, G.C., Marty, M. Standard operating procedures of the electrochemotherapy: instructions for the use of bleomycin or cisplatin administered either systemically or locally and electric pulses delivered by the CliniporatorTM by means of invasive or non-invasive electrodes. EJC Suppl. 4, 14–25 (2006).
3. Okino, M., Mohri, H. Effects of high-voltage electrical impulse and an anticancer drug on in vivo growing tumors. Jpn. J. Cancer Res. 78, 1319-1321 (1987).
4. Mir, L.M., Banoun, H., Paoletti, C. Introduction of definite amounts of nonpermeant molecules into living cells after electropermeabilization: direct access to the cytosol. Exp. Cell Res. 175, 15-25 (1988).
5. Sersa, G., Cemazar, M., Miklavcic, D. Antitumor effectiveness of electrochemotherapy with cis-diamminedichloroplatinum(II) in mice. Cancer Res. 55, 3450–3455 (1995).
6. Sersa, G., Cemazar, M., Miklavcic, D., Rudolf, Z. Electrochemotherapy of tumours. Radiol. Oncol. 40, 163–174 (2006).
7. Miklavcic, D., Beravs, K., Semrov, D., Cemazar, M., Demsar, F., Sersa, G. The importance of electric field distribution for effective in vivo electroporation of tissues. Biophys. J. 74, 2152-2158 (1998).
8. Miklavcic, D., Corovic, S., Pucihar, G., Pavselj, N. Importance of tumour coverage by sufficiently high local electric field for effective electrochemotherapy. EJC Suppl. 4, 45–51 (2006).
9. Sersa, G., Jarm, T., Kotnik, T., Coer, A., Podkrajsek, M., Sentjurc, M., Miklavcic, D., Kadivec, M., Kranjc, S., Secerov, A., Cemazar, M. Vascular disrupting action of electroporation and electrochemotherapy with bleomycin in murine sarcoma. Brit. J. Cancer. 98, 388-398 (2008).
10. Mir, L.M., Belehradek, M., Domenge, C., Orlowski, S., Poddevin, B., Belehradek, J. Jr., Schwaab, G., Luboinski, B., Paoletti, C. Electrochemotherapy, a new antitumor treatment: first clinical trial. C. R. Acad. Sci. III 313, 613–618 (1991).
11. Mir, L.M., Glass, L.F., Sersa, G., Teissie, J., Domenge, C., Miklavcic, D., Jaroszeski, M.J., Orlowski, S., Reintgen, D.S., Rudolf, Z., Belehradek, M., Gilbert, R., Rols, M.P., Belehradek, J.Jr., Bachaud, J.M., DeConti, R., Stabuc, B., Cemazar, M., Coninx, P., Heller, R. Effective treatment of cutaneous and subcutaneous malignant tumours by electrochemotherapy. Brit. J. Cancer 77, 2336–2342 (1998).
12. Gothelf, A., Mir, L.M., Gehl, J. Electrochemotherapy: results of cancer treatment using enhanced delivery of bleomycin by electroporation. Cancer Treat. Rev. 29, 371-387 (2003).
13. Byrne, C.M., Thompson, J.F., Johnston, H., Hersey, P., Quinn, M.J., Hughes, M., McCarthy, W.H. Treatment of metastatic melanoma using electroporation therapy with bleomycin (electrochemotherapy). Melanoma Res. 15, 45–51 (2005).
14. Sersa, G. The state-of-the-art of electrochemotherapy before the ESOPE study: advantages and clinical uses. EJC Suppl. 4, 52–59 (2006).
15. Sersa, G., Miklavcic, D., Cemazar, M., Rudolf, Z., Pucihar, G., Snoj, M. Electrochemotherapy in treatment of tumours. EJSO 34, 232-240 (2008).
16. Marty, M., Sersa, G., Garbay, J.R., Gehl, J., Collins, C.G., Snoj, M., Billard, V., Geertsen, P.F., Larkin, J.O., Miklavcic, D., Pavlovic, I., Paulin-Kosir, S.M., Cemazar, M., Morsli, N., Soden, D.M., Rudolf, Z., Robert, C., O’Sullivan, G.C., Mir, L.M. Electrochemotherapy – an easy, highly effective and safe treatment of cutaneous and subcutaneous metastases: results of ESOPE (European Standard Operating Procedures of Electrochemotherapy) study. EJC Suppl. 4, 3–13 (2006).
17. Quaglino, P., Mortera, C., Osella-Abate, S., Barberis, M., Illengo, M., Rissone, M., Savoia, P., Bernengo, M.G. Electrochemotherapy with intravenous bleomycin in the local treatment of skin melanoma metastases. Ann. Surg. Oncol. 15, 2215-2222 (2008).