Metronomic Chemotherapy: Direct Targeting of Cancer Cells after all?

Metronomic chemotherapy (MC) was initially described as an antiangiogenic therapy more than 15 years ago. Over the past few years, additional data have highlighted the impact of MC on the microenvironment beyond angiogenesis, with, most importantly, a potential impact on the immune system. Here, we review and reappraise the fact that MC might be able to directly kill cancer cells. Although long neglected, this question is of critical importance both fundamentally and clinically, especially when considering future associations with immunotherapies.