Cancer cells are more likely to attack the healthy areas of the body during the night when the affected individual is asleep, a new study has suggested. Cancer cells go through a process called metastasis where they break away from the primary tumour and mingle in the bloodstream to affect other parts of the body.
The study, published in Nature, was a collaborative effort of researchers at ETH Zurich, University of Basel, and the University Hospital Basel. It suggests that these cancer cells have a high activity in the blood stream when the affected person is asleep during the night. Conducted on breast cancer patients, the team of researchers found that the circulating tumour cells (CTCs) are significantly higher in number in the bloodstream during the night as compared to the day.
“When the affected person is asleep, the tumour awakens,” summarised Nicola Aceto, professor at ETH Zurich, in a statement. The researchers included 30 female cancer patients and studied the activity of CTCs in them. They found that not only is the dissemination increased when the host is asleep, the tumour gets divided more quickly during that time too. The CTCs, during the night, gain more potential to effectively indulge in metastases.
Researchers found that the escape of the CTCs from the original tumour into the bloodstream was controlled by melatonin, a hormone that determines the rhythms of day and night for the body. The study also gave insight into how timing of tests and samples can influence the findings of the oncologists.
“Some of my colleagues work early in the morning or late in the evening. Sometimes they will also analyse blood at unusual hours,” said Aceto. It was a matter of wonder how the circulating tumour cells showed varied composition depending on the time of the day.
According to Aceto, the study indicates that healthcare professionals must systematically record time at which they perform biopsies.
The study also lays foundation to various modifications possible in cancer treatments. The next that researchers want to investigate is if existing therapies can be made more effective if done at different times during the day.
