[Tumor dormancy therapy--what do you think of this therapy?]

Abstract

The phrase tumor dormancy means that all tumor cells are in cell-cycle arrest. What then is tumor dormancy therapy? It is theoretically predicted that a poor environment for tumor tissue may induce tumor dormancy; an example is interruption of the tumor blood circulation. Some non-cytotoxic drugs in cancer treatment, for example angiogenesis inhibitors, may be able to induce and maintain tumor dormancy. Recently, some clinician groups in Japan have posited that tumor dormancy can be induced by low-dose chemotherapy. They assert that the aim of low-dose chemotherapy is to prolong time to progression (TTP), not to kill the cancer cells, so it may reasonably be called "tumor dormancy therapy". However, there is no evidence that survival is prolonged and tumor dormancy induced by low-dose chemotherapy. Tumor dormancy and prolonging TTP are very different matters. The term "tumor dormancy therapy" is better not used in cancer chemotherapy using cytotoxic drugs.