A Polish study of more than 50,000 volunteers screened for colon cancer has found far more cases among men than women, a discovery suggesting that colonoscopy guidelines may need to be revised.
The rate of advanced neoplasia, a description that includes actual tumors and large growths that could lead to cancer, was 73 percent higher for men than women regardless of age, the researchers report in Thursday's issue of the New England Journal of Medicine.
The team, led by Jaroslaw Regula of the Maria Sklodowska-Curie Memorial Cancer Center in Warsaw, estimates that among people age 50 to 54, only 17 men would have to be screened to find one case of advanced neoplasia.
That compares with 28 women, according to the study.
The study defies conventional wisdom among cancer experts.
The American Cancer Society, for example, says that colorectal cancer is just as common among women as men.
It estimates about 150,000 Americans will be diagnosed with colorectal cancer this year, and more than 55,000 will die, making it the second biggest cause of cancer death among men and women in the United States after lung cancer.
Globally, the World Health Organization says colon cancer will kill 655,000 people this year.
Under current guidelines, people age 40 with a family history of the disease should begin regular colonoscopy screenings. For those with an average risk, the test should be done at regular intervals beginning at age 50.
But those guidelines do not take gender into account.
"It is generally accepted that the lifetime risk of colorectal cancer is similar among men and women," the researchers wrote.
Using records generated with the start of a national colon cancer screening program launched in 2000, they found advanced neoplasia in 2,553, or 5.9 percent, of the volunteers aged 50 to 66 and in 243, or 3.4 percent, of those aged 40 to 49 who had a family history of the disease.