HT protects against rectal cancer in women

Digestive Disease Week 2008

Oral contraceptives do not appear to provide protection against rectal cancer, according to data presented at Digestive Disease Week 2008.

“There are significant differences in the rates of colorectal cancer between men and women,” said Millie Long, MD, a fellow in gastroenterology at the University of North Carolina, Chapel Hill. “These data may explain the lower incidence of rectal cancer in women and suggest that hormones may play a significant role in the chemoprevention of rectal cancer.”

Long and colleagues analyzed whether there was a relationship between the use of oral contraceptives or hormone therapy with rectal cancer and whether the associations were different according to the duration of use.

They collected data on oral contraceptive use, hormone therapy use, duration of use, patient demographic and risk factors by conducting in-person interviews of women enrolled on the North Carolina Colon Cancer Study-II. This was a population-based case-control study of incident rectal cancer conducted between 2001 and 2006.

For this study, the researchers identified 443 women with rectal cancer from the North Carolina Colon Cancer Study-II. They also included 405 women controls that were identified by randomized recruitment using North Carolina DMV records.

Ever use of hormone therapy was associated with a reduced incidence of rectal cancer, with an odds ratio of 0.52 (95% CI, 0.38-0.72). The reduction was higher with increased duration of hormone therapy use.

The incidence of rectal cancer was not influenced by the ever use of oral contraceptives. The duration of oral contraception use had no effect on the incidence of rectal cancer. There were also no differences on the effects of oral contraception or hormone therapy according to race or specific location of the cancer. – by Emily Shafer

For more information:
Long M, Martin C, Sander RS. #421. Presented at: Digestive Disease Week 2008; May 17-22; San Diego.