Metronomic Chemotherapy: Low Dose Less Toxicity Anticancer Strategy

Metronomic chemotherapy is the frequent administration of chemotherapy drugs at doses below the maximum tolerated dose and with no prolonged drug?free break. It thus achieves a sustained low blood level of the drug without significant toxic side?effects. Metronomic therapy leads to sustained plasma concentration of the drug without significant toxic side?effects and hence there is reduced need for supportive therapy. However in case of conventional therapy toxicity is a concern. Metronomic chemotherapy exerts both direct and indirect effects on tumor cells and their microenvironment. It can inhibit tumor angiogenesis, stimulate anticancer immune response and also induces tumor dormancy. Optimizing a metronomic anticancer therapy is still a challenging task. New strategies are being developed to combine metronomic chemotherapy with conventional chemotherapy, radiotherapy and/or targeted therapy. An important disadvantage of this type of regimen is the empiricism in finding the optimal low?dose and in monitoring therapeutic efficacy during the course of treatment.