"Women may be overwhelmed with mixed messages about physical activity or exercise recommendations and opt to be inactive because they feel that they cannot meet the recommended amount of physical activity," said Kirsten Moysich, senior author of both studies.
"Our findings suggest that any amount of regular, weekly recreational physical activity may reduce the risk for and improve survival from ovarian cancer, while a lack of regular exercise throughout adulthood is associated with an increased risk of developing and dying from ovarian cancer," Moysich, a professor of oncology at Roswell Park Cancer Institute, in Buffalo, N.Y., said in an institute news release.
In one study, the researchers analyzed data from more than 8,300 ovarian cancer patients and more than 12,600 women without ovarian cancer. Those who said they had done no recreational physical activity during their lives were 34 percent more likely to develop ovarian cancer than those who exercised regularly, the researchers found.
The link between inactivity and a higher risk of ovarian cancer was seen in both normal-weight women and those who were overweight or obese, according to the study. The findings were recently published online in the journal Cancer Epidemiology, Biomarkers & Prevention.
The other study of more than 6,800 ovarian cancer patients found that women who were inactive in the years before the diagnosis were 22 percent to 34 percent more likely to die of the disease than those who had done at least some regular weekly exercise. Again, this was true in both normal-weight women and those who were overweight or obese.
The study was published online June 14 in the British Journal of Cancer.
"While the current evidence regarding the association between different amounts of physical activity and ovarian cancer remains mixed, our findings demonstrate that chronic inactivity may be an important independent risk and prognostic factor for ovarian cancer," said Rikki Cannioto, first author of both studies and a research affiliate at the cancer institute.
Less than 45 percent of ovarian cancer patients survive five years, the researchers said in background notes. While these studies can't prove that exercise would prevent these cancer deaths, they suggest regular exercise could be of benefit.
The American Cancer Society has more on ovarian cancer.
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