The fundamental principle of any chemotherapy is the effect on the structures and processes in the ?aggressor? cells, different from those in the ?host? cells. In case of antitumor therapy, this task is extremely difficult, because, unlike infectious diseases where the cells of the causative agent are different from the ?host? cells, the tumor cells develop from the host cells, significantly complicating identification of the ?weak? link. As a result of suppression of the genes that inhibit the development of a tumor and / or transformation of proto-oncogenes into oncogenes, tumor cells start growing. At the same time, rapid development of these cells, which requires the presence of growth factors, intensive nucleic acid metabolism, suppression of apoptosis processes, aneed to create additional specific blood vessels, is the potential target for antitumor agents.
Types of Antitumor Therapy
Chemotherapy which can be cytotoxic, hormonal, targeted, as the only therapy method, without radical surgical removal of the tumor or radical radiation therapy, is administered for a limited number of malignant tumors (leukemia, lymphoma, germ cell tumors, choriocarcinoma, Ewing?s sarcoma / osteosarcoma, nephroblas-toma in children).
Adjuvant (?supplementary?) chemotherapy is a method of antitumor therapy resorted to after surgery in the absence of express metastasis, but directed against possible latent metas-tases, for example, chemotherapy after surgery for breast cancer.
Neoadjuvant chemotherapy is similar to adjuvant therapy, but it precedes the surgery. It allows reducing the tumor to a size that allows for an organ-preserving surgery, for example, in case of laryngeal cancer.
Palliative therapy is performed to reduce the size of the primary tumor and metastasis to support vital functions.