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Researchers say different cancer treatments may be more effective at certain times of day. Povozniuk/Getty Images
  • Circadian rhythms are our internal body clocks that regulate our sleep patterns and other functions.
  • Now, researchers say they may also be a way to monitor when certain types of cancers metastasize.
  • They say this information can be used to determine what time may be most optimal for certain types of cancer.

A new review paper reports that cancer is intrinsically linked to the body’s circadian rhythms.

The researchers note that this timing could help medical professionals determine what time of the day a treatment may be most effective.

Researchers from the ETH Zurich, a private research university in Switzerland, released their findings today in the scientific journal Trends in Cell Biology.

Experts interviewed by Healthline say that the data is in line with our understanding of the role of circadian rhythms in human biology.

They add that applying these lessons in cancer treatment creates the potential for a low-cost intervention with positive results.

One of the many things that virtually all living creatures have in common is the need to rest and recharge every day by following a daily cycle of approximately 24 hours.

The name given to this, circadian rhythm, originates from a Latin phrase: circa dies, which means approximately day.

Circadian rhythms have been understood, to some degree, for centuries. However, the new data shows an intriguing layer to the process.

Researchers say that since circadian rhythms dictate cellular function within the body and because cancer spreads via cells, the spread of cancer differs throughout the day. For instance, breast cancer tends to metastasize at night while prostate cancer does the same during the day.

By applying this data, the researchers say it stands to reason that administering treatments such as chemotherapy and immunotherapy at certain targeted times of the day can yield better results.

Dan Ford, a licensed psychologist who specializes in insomnia treatment and serves as clinical director at The Better Sleep Clinic in Auckland, New Zealand, told Healthline that these findings match up with the current understanding of how circadian rhythms work.

“Because most biological organisms have predictable rhythms that increase and decrease in strength throughout the day, we can improve the effectiveness of medications and other interventions, and therefore treatment outcomes, by paying attention to when we time their delivery,” Ford explained.

“In fact, circadian-related changes are recognized in more than 100 different medications and there are guidelines when to take these drugs for specific illnesses, including for cancer and for cardiovascular disease,” he added.

Dr. J. Wes Ulm, a physician, medical researcher, and bioinformatics expert based in the United States, said the effective timing of cancer interventions is a low-cost way to boost the treatment.

“This is accomplished by applying cell and molecular biology-based insights into the daily variation of processes that govern the pathophysiology of cancer cells — the particular facets of how they pose a disease burden, in particular their growth and spread to other tissues,” he told Healthline.

Human sleeping patterns can vary significantly, with disorders such as insomnia and commitments like shift work affecting a person’s ability to get a good night’s sleep.

“Genetics and age can influence how late or early the body clock runs,” said Ford. “Extremely late clocks, what we commonly term ‘night owls,’ can interfere with a person’s ability to fall asleep or get up at times that meet work, study, or life obligations, and can be diagnosed with delayed sleep phase disorder. Likewise, extremely early clocks or ‘morning larks’ can potentially be diagnosed with advanced sleep phase disorder.”

While life commitments might shift sleep schedules around, this can be mitigated somewhat by following a set schedule.

“The human body prefers a somewhat predictable routine, with regularity in sleep and wake cycles and concomitant (naturally occurring) exposure to sunlight and external stimuli,” explained Ulm. “Staying at least broadly in sync with such rhythms helps the body’s circadian-dependent systems to strike the right balance and better achieve homeostasis, or the maintenance of well-functioning cellular processes that contribute to overall health.”

Ulm added that following your rhythms is important for many reasons, pointing out that it’s virtually unheard of in the natural world for any species to evolve so it can go without sleep or ignore its daily rhythms.

“This, among other observations, bolsters the case that regular sleep and recovery are imperative at a fundamental biological level for good cell and tissue function, essentially helping our bodies to heal their components and better carry out elemental tasks like cellular repair and learning consolidation,” he said.

“American work and social culture especially are often in direct conflict with achieving this, but based on the outcomes of recent research, adequate rest and ‘circadian hygiene’ are pivotal enough to warrant prioritizing them in one’s calendar and general planning,” Ulm added.