Information from www.pcrm.org:
A recent study from the Ontario Family Colorectal Cancer Registry, established by the U.S. National Cancer Institute, compared the diets of people who had been diagnosed with colorectal cancer to the diets of people who did not have cancer. It turned out that those who ate the most red meat had a 67 percent higher risk of colorectal cancer, regardless of any genetic factors they may have had.
However, some people with specific genes had a much higher risk from meat-eating—up to four times the cancer risk—compared to people who avoid meat.
Every year, 160,000 Americans are diagnosed with colorectal cancer. About half of all cases are already incurable when they are found.
Cotterchio M, Boucher BA, Manno M, Gallinger S, Okey AB, Harper PA. Red meat intake, doneness, polymorphisms in genes that encode carcinogen-metabolizing enzymes, and colorectal cancer risk. Cancer Epidemiology Biomarkers and Prevention. 2008;17:3098-3107.
