Abstract
Chronotherapy consists of chemotherapy delivery according to circadian rhythms. These genetically based rhythms modulate cellular metabolism and cell proliferation in normal tissues. As a result, both the host tolerance and antitumor efficacy of 5-fluorouracil (5-FU) and oxaliplatin (l-OHP), like 30 other anticancer drugs, vary largely according to the dosing time in laboratory rodents. The transfer of this concept to the clinic is aimed primarily at increasing the dose-intensity of the therapy through adjustment of drug-delivery to 24h rhythms in host tolerance. A specific technology (programmable-in-time infusion pumps) enables administration of chronotherapy to fully ambulatory patients. Phase I–III clinical trials show chronotherapy significantly increases tolerance to high doses of cancer drugs and improves antitumor activity in patients with metastatic colorectal cancer. These safe conditions of drug-delivery led to the first demonstration of the high activity of the 5-FU–leucovorin–l-OHP protocol. Chronotherapy with these three drugs also allows surgical removal of previously unresectable liver and lung metastases. This novel medico-surgical management provides hope for the cure of metastatic disease in patients with unresectable colorectal cancer metastases.