Hormone therapy protects against colon cancer
The use of hormone therapy in older women is associated with a significantly lower colorectal cancer risk, however, the mechanisms for the apparent protective association are still unclear, according to a study led by the United States Mayo Clinic.
The research, presented at the recent annual meeting of the American Association for Cancer Research, was designed to look at possible links between estrogen exposure and colon cancer molecular subtypes, to determine how these hormones might function in fighting the onset of cancer.
“In our large, prospective study, use of hormone therapy seemed to be beneficial with respect to reducing colorectal cancer risk – women who did use these drugs had a 28% lower incidence rate than women who did not use these drugs,” says the study’s lead author, Dr David Limsui, a fellow in the Department of Gastroenterology at Mayo Clinic’s campus in Rochester, Minnesota.
“But we still don’t know how estrogen compounds work in cancer prevention, which is intriguing.”
Women who reported using other hormone preparations, such as oral contraceptives, did not appear to derive any colorectal cancer prevention benefits.
“Based on our findings, we need to continue exploring the cancer pathways that might be affected by these hormones,” Dr Limsui said.
He adds that other studies have also found that hormone therapy protects postmenopausal women against colon cancer.
The largest randomised clinical trial was the 16,000 participant Women’s Health Initiative, which concluded in 2004 that combination hormone therapy (estrogen and progestin) reduced a woman’s risk of colorectal cancer by about 40%, he says.
“But few studies have delved deeper to see how these hormones work at the molecular level,” Dr Limsui said.
