Timing Cancer Treatment to the Body’s Natural Biological Clock

Circadian rhythms are associated with significant differences in chemotherapy efficacy and toxicity depending on the time of day.

• Marked time-of-day variations in the effectiveness and side effects of chemotherapy, targeted agents, and immunotherapies have been consistently observed in experimental models.
• Chronomodulated chemotherapy using fluoropyrimidines, platinum compounds, and anthracyclines has shown reproducible reductions in treatment-related toxicity in clinical studies.
• Survival outcomes related to chronomodulated treatment can vary and may depend on sex.
• Emerging evidence suggests that the timing of immune checkpoint inhibitor administration may impact both progression-free and overall survival across various tumor types.
• Challenges in implementing chronotherapy in routine oncology practice include individual differences in circadian rhythms, tumor-specific disruptions, and logistical issues with time-specific drug delivery.

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