Alcohol use, tobacco use, and male gender are all risk factors for earlier onset of colorectal cancer and may one day be used to individualize screening recommendations, according to a new report.

"Most medical groups recommend colon cancer screening at age 50 because that's when the risk really goes up," senior author Dr. Hemant K. Roy, from Northwestern University in Evanston, Illinois, told Reuters Health. "Aside from considering a person's family history of colon cancer, screening really isn't individualized."

Our results support the notion that a "one-size-fits-all" approach is not the best way to screen for colorectal cancer, Dr. Roy said. In particular, "screening should possibly start earlier than 50 years of age in alcohol and tobacco users."

The new findings, which appear in the Archives of Internal Medicine for March 27, are based on analysis of data for 161,172 patients who were diagnosed with colorectal cancer between June 1, 1993 and December 31, 2003.

Current drinkers or smokers developed cancer, on average, 5.2 years earlier than their counterparts who did not drink or smoke. Current drinking and smoking hastened the onset of disease by 7.8 years. Current drinkers and smokers were also slightly more likely to have distal location for their malignancy.

Cancer onset in men was 1.9 years earlier than in women (p < 0.001). Distal disease sites were also more common in men.

The effect of smoking on disease onset was stronger in women than in men. Women smokers developed cancer 6.3 years earlier than their peers who did not drink or smoke compared with 3.7 years in men.

"Smoking and alcohol use are generally accepted risk factors for colorectal cancer, but I was somewhat surprised at the magnitude of the effect they had on disease onset," Dr. Roy said.

Although confirmation in other studies is needed, "our findings are very intriguing and may lead to tailored recommendations for colorectal cancer screening," Dr. Roy noted.