Men might need to be screened for colorectal screening at an earlier age than women, a new study suggests.

Most national guidelines recommend screening for colorectal cancer by age 50 for both men and women of average risk. 

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Colonscopy is considered the most effective way to check for the early signs of colorectal cancer. (Jean-Paul Pelissier/Reuters)

When Austrian researchers analyzed the results of more than 40,000 colonoscopies, they found that men had a higher rate of advanced tumours at ages 40 to 49, a decade earlier than women.

The finding "indicates a significantly higher rate of these lesions among men compared with women in all age groups, suggesting that male sex constitutes an independent risk factor for colorectal carcinoma and indicating new sex-specific age recommendations for screening colonoscopy," Dr. Monika Ferlitsch of the Austrian Society for Gastroenterology and Hepatology in Vienna and her co-authors concluded in Wednesday's issue of the Journal of the American Medical Association.

The study was conducted between 2007 and 2010. Participants had an average age of 60 and there was about the same number of men and women.

Participants had colonoscopy screenings to look for adenomas or benign polyps as well as advanced adenomas and colorectal cancer.

Earlier screening under study

Among men aged 50 to 54, five per cent had advanced adenoma compared with 2.9 per cent of women.

The researchers also estimated the number needed to screen — how many people need to be screened for a given time to prevent one death or adverse event. The higher the number, the less effective the screening.

In 50- to 54-year-old women, the number needed to screen was nearly twice as high as in men at the same age: 9.3 compared with 5.4.

The study's authors called for more research to show how effective screening is at different ages before current screening recommendations are reconsidered.

They noted limitations of their study. For example, age and sex were considered but other risk factors such as family history, obesity and smoking were not. The study also included only a small number of patients younger than 30.

In the U.S., the American of Gastroenterology recommends screening African-Americans starting at age 45 because of a higher incidence of colorectal cancer at a younger age and higher mortality compared with white individuals, the researchers said.

Approximately 22,200 new cases are expected to be diagnosed in Canada in 2011, and roughly 8,900 Canadians will die from the disease this year.

The study was funded by the Fund for Preventive Check-ups and Health Promotion.