Study results suggest that hormone replacement therapy (HRT) that combines estrogen with progestin may dramatically reduce a women’s risk of developing colorectal cancer.
Jill R Johnson and colleagues at University of Minnesota School of Public Health studied data from 56,733 postmenopausal women who participated in the Breast Cancer Detection Demonstration Project follow-up study. Results showed that use of any type of estrogen HRT was associated with an overall 17% reduced risk of colorectal cancer, with risk reduction climbing to 26% in those who had been taking estrogen for ten or more years.
However, results also showed that women who had ever used estrogen in combination with progestin – the combination used in the Women’s Health Initiative Study, which led to millions of women discontinuing HRT because of breast cancer fears – had a 22% reduced risk of colorectal cancer. They then went on to find that women who had used progestin sequentially or for less than 15 days a month had a 36% reduced risk. Women who had used estrogen and progestin at least five years ago were found to have a highly significant 45% reduced risk of the disease.
Johnson JR, Lacey JV, Lazovichi D, et al. Menopausal Hormone Therapy and Risk of Colorectal Cancer. Cancer Epidemiology Biomarkers & Prevention. 209;18:196-203. doi:10.1158/1055-9965.EPI-08-0596
