Cancer: Time of day may matter for diagnosis, treatment

The circadian rhythm is basically a master clock for the body.

ISLAMABAD, (Online) - The body’s circadian rhythm — the natural 24-hour cycle that happens throughout the day — has an impact on sleep.

However, previous research has also found the circadian rhythm to have an effect on a number of health concerns, including mental health disorders, epilepsy, cardiovascular disease, and diabetes.

A study in April 2021 found that a person’s circadian rhythm may influence how effective certain medications are depending on what time of day they are administered.

Now, researchers from the Swiss Federal Institute of Technology (ETH) Zurich believe that the circadian rhythm may also impact cancer diagnosis and treatment success.

The study was recently published in the journal Trends in Cell Biology.

What is the circadian rhythm?

The circadian rhythm is basically a master clock for the body.

Every day, the body goes through a cycle of processes that last for about 24 hours. This includes physical, behavioral, and mental changes, including hormonal activity and digestion. The circadian rhythm ensures the body goes through these processes.

Circadian rhythm also regulates the body’s sleep/wake cycle. During the day, the circadian rhythm helps us feel awake and alert. At night, it helps ensure the body rests through sleep.

Certain things can disrupt the body’s natural circadian rhythm, including:

• light

• unhealthy sleep habits

• shift work

• travel to a different time zone

• underlying sleep disorders.

If a person’s circadian rhythm becomes disrupted, they can have a circadian rhythm sleep disorder.

And previous studies in mice have linked disrupted circadian rhythm to cancer development.

How circadian rhythm affects cancer treatment

In this study, the research team analyzed current data known about circadian rhythm and cancer development, diagnosis, and treatment. The scientists found that metastasis — the spread of cancer cells from the original site to another area of the body — is connected to the circadian rhythm. For example, the authors state, breast cancer is more likely to metastasize at night while a person is asleep, whereas prostate cancer is more likely to metastasize at other times during the day.

The authors believe that a person’s circadian rhythm could influence the effectiveness of chemotherapy and immunotherapy treatments. A process called chronotherapy can be used to coordinate treatment delivery with the body’s circadian rhythm.

Study researchers also found that the time of day a person receives cancer treatment may impact how successful it is.

The scientists cited a study in 2021 showing that people with melanoma who received immunotherapeutic drugs before 4:30 p.m. were almost twice as likely to survive as people who received the treatment later in the day.

The research team reported that the circadian rhythm might help doctors with cancer diagnosis.

As cancer cells make proteins at different times of the day, researchers believe that knowing when these proteins are at their highest concentration can help decrease misdiagnosis and help when performing biopsies.

How might this help doctors in the future?

After reviewing this study, Dr. Santosh Kesari, a neuro-oncologist and director of neuro-oncology at Providence Saint John’s Health Center, chair of the Department of Translational Neurosciences and Neurotherapeutics at Saint John’s Cancer Institute in Santa Monica, California, and regional medical director for the Research Clinical Institute of Providence Southern California, said this is a new concept that is not yet well understood.

Dr. Kesari, who was not involved in the research, told Medical News Today that, nevertheless:

“[B]ased on a variety of mostly preclinical data, and maybe some clinical data too, it seems like the circadian rhythm can have some profound effects, not just obviously on sleep and other functions, but a lot of biology in terms of cancers developing and also treating cancers and how the circadian rhythm can affect the effectiveness of the various treatments — immunotherapy and chemotherapy — that we give patients.”

Dr. Manmeet S. Ahluwalia, deputy director, chief scientific officer, chief of medical oncology, and Fernandez Family Foundation Endowed Chair in Cancer Research with Miami Cancer Institute, part of Baptist Health South Florida, who was also not involved in this study, weighed in on the argument.

He said that, if this concept is validated in a prospective setting, in the future it may help doctors recommend treatments at a particular time of the day to enhance efficacy or minimize side effects.

“For example, in patients with ovarian cancer who receive Adriamycin in the morning and cisplatin in the evening, they experience fewer side effects than patients who received Adriamycin in the evening and cisplatin in the morning,” he noted.