People in California and other locations have a natural sleep-wake cycle called the circadian rhythm. This natural cycle controls many things about how the body works, including hormone levels. Doctors are beginning to believe that certain types of cancer respond to treatment better when the treatment is given at a particular time of day controlled by the circadian rhythm. They also think it may be easier to diagnose certain cancers earlier by looking for them at certain times. Likewise, looking for them when levels are naturally low may lead to cancer misdiagnosis.
How the circadian rhythm affects cancer
Doctors believe certain cancer types spread at night while others spread during the day. For example, researchers found that breast cancer cells were more likely to shed into the bloodstream while a person was resting. They also determined that these cells were more likely to grow, spreading breast cancer. Another team of researchers found that prostate cancer was more likely to spread when insulin levels are highest in the body, which typically occurs in the mid-afternoon.
Implications for cancer treatment
Researchers admit that their findings are preliminary, so further testing needs to be done on how it can stop cancer misdiagnosis and impact cancer treatment. Yet, it may be easier to detect cancer when hormone levels causing that cancer type are at their highest. One of the ways that the researchers would like to see their experiment expanded is to give oral cancer drugs at the time of day when the cancer is most likely spreading to see if it results in better outcomes. They admit that changing other types of cancer treatment may be much more challenging.
Early research shows that specific cancers spread at certain times of day, so researchers want to see if giving treatments at those times will result in more people recovering from cancer.