Photodynamic therapy/oncology

One of the greatest problems of the medical world is cancer, the second most important cause of death on Earth. During the last decade an increase of malignant tumors was seen in Romania, cancer being, after the cardiovascular diseases, the most frequent cause of mortality. The powerful impact of cancer on human life is obvious not only in the death rate but in the number of new cases and living diseased. Therefore, early diagnosis and treatment of cancer has become one of the priorities of the medical world. Current ways of treating cancer (surgery, radiotherapy, chemotherapy) are sometimes only palliatives, that’s why research for new methods to cure cancer is a continuous struggle around the world. Such research have lead to new ways of dealing with this disease based on the induced photochemical effect of light radiation on tumors, known as photochemotherapy or photodynamic therapy. Photodynamic therapy is a method of local treatment of the tumor by administrating a photosensitizing substance which is selectively absorbed by the tumor cells and which, during the irradiation with optical radiations, ends in destroying the tumoral tissue. Although in experimental phase, the obtained results of phototherapy in the latest period are remarkable and have lead to growing interest to this method. The application of photodynamic therapy in current practice raises some problems: the type of potosensitizer (the way of administration, how to prepare it, therapeutic concentration), the radiation source (type, irradiation parameters: wavelength, energy, exposure time, pulse duration, pulse frequency, etc), methods of determining the biologic response, etc. Until now, there are numerous studies on each of these matters. A synthesis of these studies is the subject of this article.