Sept. 29, 2009 -- Younger women with advanced colon cancer live slightly longer than younger men with advanced disease, but the survival advantage disappears as women age and their estrogen levels drop, a new study shows.
Previous research suggests a role for the female hormone in protecting against colorectal cancer. Women are less likely than men to get the disease, and they tend to be diagnosed later in life.
The new study is the first to suggest that estrogen also improves outcomes in premenopausal women and that it may help cancer treatments work better, researcher Heinz-Josef Lenz, MD, of the University of Southern California tells WebMD.
“Young women seem to be benefiting more from the latest, aggressive treatments for colorectal cancer than young men are,” says Lenz, who co-directs the colorectal cancer center at USC’s Norris Comprehensive Cancer Center/Keck School of Medicine.
Estrogen May Help Chemo Work
About 150,000 new cases of colon or rectal cancer will be diagnosed in the United States this year, and nine out of 10 cases will occur in people over the age of 50, according to the American Cancer Society (ACS).
When younger adults do get colorectal cancer, some studies suggest the disease may be more aggressive.
In the newly published research, Lenz and colleagues analyzed data from a large national cancer registry that included about 53,000 patients with advanced colorectal cancer who were diagnosed and treated between 1988 and 2004.
On average, women younger than age 45 lived longer than men of the same age -- 17 months vs. 14 months.
Survival times were about equal for women and men between the ages of 45 and 54. But as a group, older women (55 years and older) with cancer that had spread beyond the colon or rectum had a shorter survival than men -- seven months vs. nine months.
The survival advantage among young women was seen in all ethnic groups, and the gender disparity was greatest among younger patients treated after 1999.
The study appears in the Oct. 15 issue of the journal Clinical Cancer Research.
“Up until eight or nine years ago we had only one drug (5-fluorouracil) to treat colorectal cancer,” Lenz says. “Now we have many more treatment options and this research suggests that young women benefit more from these drugs than men.”
‘Too Soon to Recommend Estrogen’
It is not clear exactly how estrogen protects against colorectal cancer. One theory points to a protein called estrogen receptor beta that helps estrogen work.
As women age and their estrogen production drops, they also produce less estrogen receptor beta. This loss is emerging as an important step in the progression of hormone-dependent tumors, the researchers write.
American Cancer Society Director of Prostate and Colorectal Cancers Durado Brooks, MD, calls the study "intriguing," but he says its relevance for colorectal treatment remains to be determined.
“I can certainly see where some investigator might want to look at whether adding estrogen to chemotherapy in men and older women with colorectal cancer might make a difference in survival,” he says. “But it is way too early to recommend that as a treatment strategy.”