Aggressive Breast Cancers Tied To Lack Of Sleep
August 28, 2012

Aggressive Breast Cancers Tied To Lack Of Sleep

Connie K. Ho for — Your Universe Online

It is known that a lack of sleep can cause short-term difficulties and also a number of long-term health issues, including depression, stress, and cognitive impairment. And now, new research has also uncovered a possible link between sleep deprivation and certain aggressive forms of breast cancer.

This study was the first of its kind to demonstrate that there was a link between lack of sleep and tumors that were biologically more aggressive. The lack of sleep was also connected to the possibility of cancer recurrence. The findings were recently featured in Breast Cancer Research and Treatment.

"This is the first study to suggest that women who routinely sleep fewer hours may develop more aggressive breast cancers compared with women who sleep longer hours," explained lead author Cheryl Thompson, an assistant professor at Case Western Reserve University School of Medicine, in a prepared statement. "We found a strong correlation between fewer hours of sleep per night and worse recurrence scores, specifically in post-menopausal breast cancer patients. This suggests that lack of sufficient sleep may cause more aggressive tumors, but more research will need to be done to verify this finding and understand the causes of this association."

Research was conducted by physician-scientists from University Hospital Case Medical Center´s Seidman Cancer Center and Case Comprehensive Cancer Center at Case Western Reserve University. The team of investigators studied medical records and survey responses from 412 breast cancer patients who were post-menopausal and treated at the UH Case Medical Center with a test that looked at treatment in the beginning stages of cancer. Due to a certain expression level from the mix of 21 genes, the test, called Oncotype Dx, would give a tumor a recurrence score.

The participants also told researchers the average number of hours they slept within the last two years. Based on the results, the scientists concluded that women who had slept an average of six hours or less before their breast cancer diagnosis also scored higher on their Oncotype Dx tumor recurrence exams. Even though there was a strong correlation between lack of sleep and high tumor recurrence scores for women who were post-menopausal, this same association was not seen in menopausal women. The researchers believe that there are different factors at play for pre-menopausal and post-menopausal breast cancers.

Overall, the data pooled from the study shows that sleep could impact carcinogenic pathways that are related to the progression of post-menopause breast cancer and not pre-menopausal cancer.

"Short sleep duration is a public health hazard leading not only to obesity, diabetes and heart disease, but also cancer," noted study co-author Dr. Li Li, a family medicine physician in the Department of Family Medicine at UH Case Medical Center and Associate Professor of Family Medicine, Epidemiology and Biostatistics at Case Western Reserve University School of Medicine, in a prepared statement. "Effective intervention to increase duration of sleep and improve quality of sleep could be an under-appreciated avenue for reducing the risk of developing more aggressive breast cancers and recurrence."

The study was funded by grants from the National Cancer Institute.