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| |  AACR: Hormone Replacement Therapy Not Beneficial In Preventing Polyp Recurrence By Cameron Johnston Special to DG News
NEW ORLEANS, LA -- March 28, 2001 -- A study by the National Cancer Institute has determined that hormone replacement therapies (HRT) do not lessen the risk of colorectal cancer or the formation of colonic polyps among peri- or post-menopausal women. This runs contrary to 12 previous studies that have suggested a protective benefit against colorectal cancers among older women who were using HRT. The study looked prospectively at 620 peri- and postmenopausal women who were enrolled in a dietary intervention study. They all received a colonoscopy at baseline, then again at the one-year and four-year time points. All had had at least one polyp removed within six months of being randomized to the study. There is some biological rationale for the idea that hormone use would reduce the risk of adenoma formation, explained Karen Woodson, one of the principal investigators on the study. On one hand, steroids are thought to suppress bile acid production and bile acid is thought to promote adenomatous formations. Estrogen receptors are also found in colonic tissues and estrogen is also thought to enhance absorption of calcium by colonic tissue. The Polyp Prevention Trial contradicted the findings of previous studies that suggested a gastroprotective benefit to hormone use. Overall, the rate of polyp recurrence was 30 percent among those women of any age who used any form of HRT versus 70 percent for those who did not have any polyp recurrence but were using HRT. Among those who were not using HRT, the rate of polyp recurrence was 34 percent, while for those who were not using HRT and did not have a recurrence, the rate was 66 percent. When the data is broken down into sub-groups, based on whether the women were under or over the age of 62, the results were somewhat different. Among those under 62 years of age, there was a 32 percent recurrence rate among HRT users versus a 21 percent recurrence rate among non-users. However, among those over the age of 62, there was a 26 percent recurrence rate among HRT users and a 43 percent recurrence rate among non-users. "This is the first prospective study to report an increased risk among younger women," Dr. Woodson said. "The increased risk in younger women was confined to the proximal bowel where we observed a three-fold risk increase for adenoma recurrence (nine percent versus 30 percent among HRT users versus non-users). However, among older women, the reduction in risk was seen in the distal and proximal bowel." In the older sub-group, the recurrence rate was 42 percent among non-HRT users and 11 in HRT-users for proximal polyps, and 34 percent in non-HRT users versus three percent for HRT users for distal polyps. "In conclusion, we saw no overall association between current hormone use and adenoma recurrence. But in the sub-group analysis, we saw an inverse association between HRT and adenoma recurrence in older women, but an increase risk in younger women. The increased risk in younger women was limited to the proximal bowel, while the reduced risk observed among older women was observed in both the proximal and distal bowel."
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