Research in monkeys suggests the possibility that stress may increase risk for the most common type of uterine cancer, according to a report from Wake Forest University Baptist Medical Center.
The study results also suggest that two drinks a day won’t increase breast or endometrial cancer risk for postmenopausal women who don’t take estrogen.
The results are reported in the current issue of Menopause, the journal of the North American Menopause Society.
“The results from this study tell us that we need to look much more closely at the effects of stress and socioeconomic status on risk for endometrial and breast cancer in women,” says Carol Shively, Ph.D., professor of comparative medicine at Wake Forest Baptist.
“The outcome of this study is a precautionary tale,” said Kathleen Grant, Ph.D., (co-author), in an editorial about the research. “Social stress, perhaps caused by increases in social isolation and hostile social experiences, or lack of control over social interactions, may place postmenopausal women at risk for breast and endometrial cancer.”
Shively and colleagues studied the effects of stress and moderate alcohol consumption on breast and endometrial tissue, which is the lining of the uterus. They evaluated type and quantity of cells, density of tissue, number of dividing cells, and number of progesterone and estrogen receptors. Levels of sex steroids, such as estrogen, and adrenal steroids, such as cortisol, were also measured. All of these may be markers for cancer risk.
For the study, postmenopausal female monkeys were placed in groups so they would naturally establish a social hierarchy from dominant to subordinate. Previous research has shown that subordinate monkeys have increased heart rates, more of the stress hormone cortisol and more cardiovascular disease. The current study showed that compared to dominant monkeys, the socially stressed subordinate monkeys were at increased risk for endometrial cancer, which affects 1 percent to 2 percent of women and is most common in older women.
“We know that lower social status is stressful for both humans and monkeys,” said Shively. “This study shows that in monkeys, social stress was associated with cellular changes that may increase endometrial cancer risk.”
The subordinate monkeys also had changes in their breast tissue, but these were not as significant as the uterine changes. “There may be an effect, but it’s not as strong as in the uterus,” said Shively.