In a study published in the Journal of Cancer Research, Dr. Fahed Hakim, of Rambam Health Care Campus, concluded that poor-quality sleep marked by frequent awakenings can speed cancer growth, and increase tumor aggressiveness, malignancy, and invasiveness. This is the first time a connection has been made between poor sleep and cancer.
For the project, Hakim, a pediatric pulmonary and sleep expert at Rambam, spent two years at the University of Chicago, and led a joint team, composed of researchers from that institution and the University of Louisville.
While studies have long connected fragmented sleep with fatigue and irritability, this research project indicated far more dramatic effects. According to Hakim, over the long term, disrupted sleep dampens the immune system’s ability to eradicate tumor cells and contributes to the spread of the disease.
Hakim and his fellow researchers observed two sets of mice. One group was allowed to sleep normally, while the other had its sleep interrupted. The mice were injected with two different types of cancer cells—all the mice began to develop malignant tumors. After a month, the researchers found that tumors of mice with fragmented sleep were twice as large as those from mice that had slept normally.
In a subsequent experiment, researchers found that the cancerous tumors in sleep-disrupted mice were not only larger, but more malignant and aggressive than those in mice that slept normally. The tumors of the sleep-disrupted group were not static, but invaded surrounding muscle and bone tissues.