Research: Breast cancer cells mainly spread quickly when the patient sleeps

Breast cancer is the number one cancer in the world. In 2020, around 2.3 million people worldwide will be diagnosed with breast cancer. 99% of breast cancer cases are in women, most of them age 40 or older.

The key to successful treatment of breast cancer is early diagnosis. Cancers that are localized to the milk ducts or lobules are less likely to spread and can often be treated effectively.

However, once breast cancer begins to produce circulating tumor cells (CTCs), they can spread throughout the body through the bloodstream, forming metastatic or secondary tumors. Once this happens, the cancer becomes more difficult to treat.

Now, a research team from the Swiss Federal Institute of Engineering (ETH), the University Hospital of Basel and the University of Basel has found that: compared with when the patient is awake, when the patient is asleep, CTCs spread and much faster division.

Research published in the journal Nature shows that time-controlled therapy may be effective for metastatic breast cancer.

(Screenshot of the study posted on Nature)

The study first looked at a group of 30 women, 21 of whom had early stage (not yet metastatic) breast cancer and 9 of whom had stage IV metastatic disease. The study took blood samples at 10:00 a.m. (active) and 4:00 a.m. (sleeping) to analyze the CTCs of these samples: the surprising finding that nearly 80% of the CTCs were found in the CTCs. Blood samples were taken while sleeping.

The same study was then done in a mouse model of breast cancer. In mice, the study found that most of the CTCs present in the samples were taken during the day, which is the time when these nocturnal mammals are resting, since rats have opposite circadian rhythms to humans.

In addition, the study found that compared with other times, during the patient's rest period, the multiplication of CTC-type cells was superior, leading to the cancer cells having the ability to metastasize or spread. spread better. The cells in the primary breast tumor also proliferate more rapidly during rest.

Detecting CTCs that spread more rapidly at night could be useful for both the diagnosis and treatment of breast cancer.

The findings may indicate that healthcare professionals need to systematically document when they do biopsies, said Nicola Aceto, professor of molecular oncology at ETH Zurich, who led the study. .

Dr Kotryna Temcinaite, director of research communications at UK charity Breast Cancer Now, said the findings show how important the timing of breast cancer treatment is.

Professor Aceto and his team plan to study whether other cancers exhibit similar symptoms, to determine whether changing the duration of treatment can make cancer treatment more effective. or not.