Timing chemotherapy with body clock may improve cancer treatment

When it comes to treating cancer, most of us focus on the type of drugs used, the dosage, and the overall treatment plan. However, new research shows that timing might be just as important. Scientists have discovered that aligning chemotherapy and other cancer treatments with our body's natural biological rhythms — known as the circadian clock — can significantly improve the effectiveness of these treatments.This emerging field is called chronotherapy.
What is the Circadian Clock?
Our bodies follow a 24-hour cycle called the circadian rhythm, which regulates everything from sleep and wakefulness to body temperature, metabolism, and cell growth. Every cell in our body, including cancer cells, is influenced by this rhythm. This internal clock influences how cells respond to external factors, including medications.
How Does Timing Affect Cancer Treatment?
Recent study has found that cancer cells, like healthy cells, are more vulnerable to certain treatments at specific times of the day. In this study, a team of scientists used advanced methods to investigate how cancer and healthy cells responded to chemotherapy drugs at different times of the day. They found that drugs can be more effective and less toxic if administered at times when cancer cells are more vulnerable and healthy cells are more resistant.
For example, one of the drugs studied, cisplatin, used to treat various cancers, was found to work best when administered in alignment with the body's circadian clock. Timing the treatment properly helped reduce the side effects in healthy cells while maximizing the drug's impact on cancer cells.
Triple-Negative Breast Cancer (TNBC) An Example
This concept of chronotherapy is especially important in the treatment of triple-negative breast cancer (TNBC), one of the most aggressive forms of breast cancer with limited treatment options. Live imaging was used to monitor the circadian rhythms, growth cycles, and medication responses of these cancer cells in real-time. Drug 5-fluorouracil (5-FU), a common chemotherapy agent, showed peak effectiveness against certain cancer cells between 8am and 10 am. The key genetic factors, known as ‘core clock genes' (genes that regulate the body's daily cycles), that heavily influence how responsive cancer cells are to treatments based on the time of day. By understanding these genes, we can better predict when chemotherapy will be most effective.
Personalized Approach To Cancer Therapy
This research is significant because it suggests that treatments could be more personalized. By understanding a patient's circadian rhythm, oncologists could plan chemotherapy at times that offer the best chance of success while reducing harm to healthy cells. This approach could be particularly important for cancers like acute myeloid leukemia (AML), where the body's natural processes, like the p53 tumor suppressor pathway (a natural defense system against cancer), are critical to treatment success.
Reducing Side Effects
One of the biggest challenges in cancer treatment is balancing the effectiveness of the therapy with the side effects. Chemotherapy often damages healthy cells, leading to unwanted side effects like fatigue, nausea, and hair loss. By using chronotherapy, doctors may be able to give cancer patients treatments at times when healthy cells are least likely to be affected, potentially reducing side effects.
While this approach is still being explored, the implications are promising.
In the future, cancer treatment could be personalized not only based on the type of cancer and genetic factors but also on the time of day — a small adjustment that could make a huge difference in outcomes. As researchers continue to explore the timing of chemotherapy treatments, the future holds promising potential for more effective, personalized cancer therapies.
(The writer is a US-based medical scientist)