According to a report published in the January issue of Cancer Epidemiology, Biomarkers and Prevention, the combination of estrogen plus progestin may decrease the risk of colorectal cancer. Many women stopped taking these hormones following the news that it may increase their risk of breast cancer.
Jill R. Johnson, M.P.H., at the University of Minnesota School of Public Health believes this may surprise many physicians: “Compared to women who had never taken these hormones, the use of estrogen plus progestin was associated with a reduced risk of colorectal cancer,” she said.
A quite significant reduction. The largest, approximately 45 percent, was seen among women who had completed use of estrogen plus progestin for five or more years previously.
Johnson and her colleagues extracted data from 56,733 postmenopausal women who participated in the Breast Cancer Detection Demonstration Project follow-up study. During an average 15 years of follow-up, Johnson and colleagues identified 960 new cases of colorectal cancer in this population. Any use of estrogen therapy was associated with a 17 percent reduced risk of that 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).
Researchers also found a 22 percent reduced risk among those who had 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.
Further studies will be conducted and, as always, women should check with their doctors to see what the latest recommendations are. At the very least, it's nice to see something positive from the hormone supplementation that many postmenopausal women had been on for years.