The current treatment buzzword is low-dose chemo. Numerous studies in leading oncology journals report that in many cancers, low-dose results are superior to standard dosing. When low-dose chemotherapy is administered on a daily schedule (known as “metronomic” because it is regular and even like the beat of a metronome) the continual death of endothelial cells attempting to form new blood vessels can substantially disrupt the angiogenic process, slowing it down notably.
One of the merits of this metronomic approach centers around cancer drug resistance. Whereas conventional, high-dose chemotherapy tends to select tumor cells that are resistant to the drugs used, metronomic chemotherapy targets normal endothelial cells that do not grow resistant to the drugs.
In other words, metronomic chemotherapy keeps on working when conventional therapy fails. Tumors may be able to adapt to a degree by increasing their production of pro-angiogenic factors that promote endothelial cells survival. This explains why cancers, which initially regress in response to metronomic therapy sometimes grow back despite continuing therapy. The cancer confers this relative resistance; not the endothelial cells themselves.