In the laboratory, the principle of this "electrochemotherapy" baptized method is already old hat. For more than twenty years, scientists have been putting cultured cells under power for a short time in order to infiltrate chemical substances or even foreign genetic material. The trick behind it: In response to extremely short electrical pulses with a high voltage, small pores form in the outer envelope of the cells, which disappear again after a short time, but in the meantime enable the most diverse substances to access the cell interior.
Some of the substances that enter cells in this way unfold unimaginable effects there. "Back in 1987, we discovered that a substance called bleomycin is one thousand to ten thousand times more lethal when it is introduced into the cells using electric fields, " says French scientist Lluis Mir, referring to ddp. Since bleomycin has been used for many years in cancer therapy, it was natural to try the method on tumors. The French therefore first treated cancers in animals and then first volunteers with the combination of chemotherapy and short electric shocks - with good success, says Mir, who works at the French National Center for Scientific Research (CNRS).
Other scientists also worked with electrochemotherapy. However, the final leap from research to practical medicine failed, according to Mir, because different groups used different devices and different approaches. "Without a standard procedure, however, it is very difficult to test a new therapy, " explains the researcher. For this reason, the European project ESOPE was launched in 2003. Under the guidance of Mir, scientists from medical centers in Ireland, Slovenia, France and Denmark worked to standardize the method and set guidelines for their application. display
At the same time, the new therapy was tested in several European clinics. A total of 62 patients with tumors on or directly under the skin who had failed other therapies were treated. "The drug bleomycin or the also commonly used chemotherapeutic agent cisplatin can be administered in two ways, " Mir explains the course of therapy. Either the patient receives an infusion so that the drug enters the bloodstream, or the drug is injected directly into the tumor. Subsequently, small electrodes are placed on the affected area or stung into the tissue and set for fractions of seconds under power. "The only important thing is that the electric field completely surrounds the tumor, " says Mir.
According to project manager Mir, of the 171 treated tumors, 75% disappeared completely and 11% decreased significantly. There were also practically no side effects, says the doctor. This is made possible by the drastically reduced drug dose, which is about 20 times lower in electrochemotherapy than with conventional chemotherapy.
The ESOPE researchers have now extended the clinical trials to other hospitals in Italy, Spain and the UK, with more to follow as soon as possible. Also a further development of the method is planned, in order to be able to use it also during an operation.
However, my German colleagues are not so euphoric when assessing the method. "This will remain a niche application, " comments, for example, the Buxtehuder dermatologist Peter Mohr, board member of the Dermatological Oncology Association. His reasoning: Electrochemotherapy can only be used in locally limited tumors, which can almost always be surgically removed. "In such a case, the operation is always preferable, because only then can be checked whether the tumor has already scattered, " said Mohr. Only in hard-to-reach places is electrochemotherapy a possible alternative.
Local application also has another drawback: while conventional chemotherapy can detect and kill cancer cells throughout the body, electrochemotherapy can only affect the cells of the primary tumor, leaving any untreated metastases unaltered Culling is the ultimate goal of chemotherapy, explains Mohr.ddp / science.de Ilka Lehnen-Beyel