Metronomic chemotherapy to treat cancer in low-resources countries

Treatment of many types of cancer is based on the use of chemotherapy. According to this approach, some special drugs, the chemotherapeutic agents, are administered in high doses which are lethal for cancer cells with the aim of eradicating them from the body. High dosage causes, however, severe side effects and drug resistance, thus chemotherapy has often to be stopped and/or becomes useless. As an alternative to conventional chemotherapy metronomic chemotherapy is gaining a great interest in the current scenario of oncological therapy. The theory behind “metronomic” chemotherapy is to administer very low doses of conventional anti-cancer drugs to attack vascular cells that supply oxygen and nourishment to the tumor (socalled “antiangiogenic” effect). The dosages are too low to kill the cancer cells directly, but high enough to arrest the growth of vessels that supply nutrients to the cancer cells. In other words, giving the drug in very low doses, and for a prolonged period of time (“metronomic” administration), such a therapy can prevent the formation of new capillaries, keeping the cancer from growing. Several studies have established the efficacy of metronomic chemotherapy in the treatment of a variety of cancer types. The efficacy seems not only to be based upon anti-angiogenic effect but also on the restoration of anticancer immune response and induction of tumor dormancy, as recently discussed by Pasquier et al. in an article which appeared in Nature Review Clinical Oncology. The chance of obtaining a successful treatment while minimizing side effects and drug resistance also means that chemotherapeutic agents can be administered in small cancer centers with minimal supportive care and this is of paramount importance to provide effective cancer treatment in the low-income and low-resources developing countries.  In fact, in many types of childhood and adult cancers, metronomic treatment protocols prove to be effective even if used on a totally outpatient basis and, most importantly, with no significant side effect. Thus the metronomic approach  represents a promising, innovative, simple, and affordable tool to treat cancer patients in the low-resources settings of the world. Metronomic protocols are now being implemented to treat leukemia and malignant lymphomas, but also cancer of the breast, ovary and the gastrointestinal tract.