A new study has shown that hormone replacement therapy can significantly reduce the risk of colorectal cancer in postmenopausal women.
The researchers found that women who had completed use of estrogen plus progestin five or more years previously were 45 pct less likely to develop colorectal cancer
"Compared to women who had never taken these hormones, the use of estrogen plus progestin was associated with a reduced risk of colorectal cancer," said Jill R. Johnson, M.P.H., a doctoral student at the University of Minnesota School of Public Health.
During the study, the research team led by Johnson extracted data from 56,733 postmenopausal women who participated in the Breast Cancer Detection Demonstration Project follow-up study.
They identified 960 new cases of colorectal cancer in this population.
The findings revealed that any use of estrogen therapy was associated with a 17 percent reduced risk in colorectal cancer.
Among those who used estrogen, the largest reductions were seen among those who were current users (25 percent reduced risk) and users of ten or more years duration (26 percent reduced risk).
However, a 22 percent reduced risk was observed among those who had ever used estrogen plus progestin in combination.
They further found a 36 percent reduction in risk among those who had used progestin sequentially or less than 15 days per month.
Past users of estrogen plus progestin, who had stopped at least five years ago, had a 45 percent risk reduction.
The study is published in the January issue of Cancer Epidemiology, Biomarkers and Prevention, a journal of the American Association for Cancer Research.