HRT use cuts colon cancer risk but linked to more advanced
disease


Posted: March 03, 2004


NEW YORK (Reuters Health) - Postmenopausal women who use estrogen and
progestin appear to have a decreased risk of colorectal cancer, data
from the Women's Health Initiative (WHI) trial indicate. However, the
cancers that do occur seem to be more advanced than those seen in non-
HRT users.


Most of the news regarding HRT in recent years has been bad. Just
this week, the National Institutes of Health announced that the
estrogen-only arm of the Women's Health Initiative (WHI) trial was
being stopped early after the therapy was tied to an increased risk
of stroke. This follows the termination of the estrogen/progestin arm
in 2002 due to an observed increase in breast cancer, thrombosis,
stroke, and heart disease events among HRT users (see Reuters Health
reports March 2, 2004 and July 9, 2002).

However, when the estrogen/progestin arm was stopped, the WHI
researchers did notice one potentially beneficial effect for HRT -- a
decreased risk of colorectal cancer, according to a report published
in The New England Journal of Medicine for March 4.

To better understand the link between HRT use and colorectal cancer,
Dr. Rowan T. Chlebowski, from Harbor-UCLA Medical Center in Torrance,
California, and colleagues analyzed data from 16,608 postmenopausal
women who participated in the estrogen/progestin arm of WHI.

Overall, HRT users were 44% less likely to develop colorectal cancer
than non-users (p = 0.003), the researchers found.

"We were quite surprised to find that colon cancers in HRT users were
of higher stage than those seen in controls," Dr. Chlebowski told
Reuters Health. The cancers that occurred in HRT users had a greater
number of positive lymph nodes (p = 0.002) and were more likely to
show regional or metastatic involvement (p = 0.004), the analysis
indicates.

"Our findings are somewhat similar to what was seen in the trial with
finasteride and prostate cancer -- overall risk is decreased but
severe disease is more likely," Dr. Chlebowski noted (see Reuters
Health report June 24, 2003). However, "in that trial, finasteride
use was tied to higher grade tumors, whereas in ours, HRT use was
linked to advanced stage disease but not to higher grade tumors," he
added.

"Interestingly, among HRT users with colon cancer, those with
antecedent vaginal bleeding were the ones most likely to have
advanced stage disease," Dr. Chlebowski pointed out. "This may have
resulted from a delay in diagnosis."

Despite all the unfavorable reports, Dr. Chlebowski believes that HRT
could still be a viable therapy. "One strategy would be to see if the
risks of HRT could be modulated with other agents," he added.