Does sex matter in colon cancer screening?

Middle-aged men are twice as likely as women to end up with a cancer diagnosis after colonoscopy, according to an Austrian study that challenges screening guidelines.

Guidelines currently advise that people at average risk of colon cancer start screening for the disease at age 50, regardless of gender.

But the new work, published in the Journal of the American Medical Association, shows a discrepancy of nearly 10 years between men and women in the development of colon and rectal tumors.

That means the same number of 55-year-old men would need to undergo colonoscopies - in this case, around 80 - to spot one cancer, as would be true for 65-year-old women. The same logic held true for the pre-cancerous growths called advanced adenomas, which doctors also scout for during colonoscopies.

However, a U.S. expert warned about making decisions regarding when to start screening based on the new findings.

"I would discourage women from looking at this study and saying, 'Gee, I can wait longer,'" said Dr. Michael LeFevre of the U.S. Preventive Services Task Force, a federally supported expert panel. "And I would discourage men from saying, 'Gee, I should start sooner.'"

Sex, Age And Ethnicity Assciated With Colorectal Cancer Survival The interaction of sex, age and ethnicity has a significant impact on overall survival in metastatic colorectal cancer (MCRC) patients, a study led by researchers at the University of Southern California (USC) and USC/Norris Comprehensive Cancer Center suggests.

While age and ethnicity are well-established factors that impact survival in colorectal cancer, the study found that gender also plays an important role in overall survival, says Andrew Hendifar, M.D., MPH, fellow in the division of hematology/oncology at the Keck School of Medicine of USC and lead author of the study. Researchers found that pre-menopausal women with metastatic colorectal cancer (18-44 years old) lived longer than younger men, while older women (75 and older) had significantly worse overall survival than older men.

The study adds to the growing evidence that female hormones are protective for colon cancer, researchers say.

"This study provides further evidence that estrogen may play an important role not only in colon cancer development but also progression of the disease, and may impact how we develop therapies for women and men with colon cancer," says Heinz-Josef Lenz, M.D., professor of medicine at the Keck School of Medicine and a senior investigator on the study.

Researchers screened 56,598 patients with metastatic colorectal cancer from 1988 to 2003, using the Surveillance, Epidemiology and End Results (SEER) registry. Models were created using the patients' age at diagnosis, sex, ethnicity and overall survival. Independent of age, there were no survival differences between men and women with MCRC. However, when age was added to the model, sex became significantly associated with survival across all ethnicities.