Three different ways of combining chemotherapy and 2-deoxy-glucose. Three different ways of combining chemotherapy and 2-deoxy-glucose: (a) First chemotherapy and later 2DG, (b) 2DG first followed by chemotherapy and (c) both administered at the same time. The first approach kills most of the sensitive cells of tumor but misses some of the resistant ones, as a consequence, the tumor perfusion is improved and more oxygen and glucose is available to the remaining cells, neutralizing the effect of 2DG. The simultaneous administration of Rx and 2DG leads to the same scenario, with sensitive and resistant cells left in a more oxygenated porous tumor mass. In both scenarios, with resistant cells free from the tumor core where they were trapped, the fraction of resistant cells will grow and tumor will slowly become more resistant. The strategy that is rewarded with most benefits is the administration of glucose competitor followed by chemotherapy, what produces a smaller sensitive tumor.