Breast cancer metastases form more efficiently when people go to bed, according to a new study.
In a new study published in the journal Nature, scientists analyzed blood samples from 30 women with breast cancer (21 patients with early breast cancer who did not have metastases, and nine patients with stage IV metastases). The researchers also conducted experiments on mice.
The results showed that 78% of the circulating tumor cells found in the blood samples were taken at night. On the other hand, a much smaller number of tumor cells were detected in the daytime samples.
The researchers also found that cells circulating at night have a higher chance of metastasis formation, as they tend to divide more rapidly.
The new discovery refutes the previous theory, according to which metastasis of breast cancer occurs at the same rate around the clock.
According to the World Health Organization (WHO), breast cancer is one of the most common forms of cancer. 2.3 million people are diagnosed with this disease every year. Metastasis is the cause of 90% of all cancer deaths.
Now researchers know that “the output of circulating cancer cells from the original tumor is controlled by hormones such as melatonin.”
The study also shows that the time during which blood samples or tumor samples are taken can change the results of the analysis.
According to scientists, medical professionals should systematically record the time at which they perform a biopsy. This approach will make the results more accurate.
The authors plan to conduct additional research to find out if there is a link between the time of day and other types of cancer.