[Metronomic chemotherapy: a new approach in cancer therapy]

Tumor angiogenesis offers a new target for anticancer therapy. In addition to the recently developed molecularly targeted antiangiogenic agents and drugs, it was found that well-know and widely applied chemotherapeutic agents, e.g. cyclophosphamide and etoposide, also show antiangiogenic activity. Unfortunately, the antiangiogenic effect of conventional anticancer therapy based on Maximum Tolerated Doses is usually limited by the treatment protocol. The cells involved in angiogenesis may regenerate during the three- to four-week interval between the doses which is applied to avoid undesired toxic effects. Taking advantage of the fact that endothelial cells are about 10-100 times more susceptible to chemotherapeutic agents than cancer cells, therapy based on daily, oral, low-dose chemotherapeutic drugs was designed. This new approach, called metronomic therapy, appears promising mainly due to the fact that its antiangiogenic and antitumorigenic effects are accompanied by low toxicity. Limited side effects, oral dosing, and no need for hospitalization makes this new therapeutic program not only more comfortable for the treated patient, but also less expensive.