Colon cancer refers to cancer of the large intestine, which is the lower part of the digestive system. Rectal cancer refers to cancer of the last section of the colon. Combined, these are called colorectal cancers.
Some factors can increase the risk of developing colorectal cancer. In particular, having certain inherited syndromes or a family history of colorectal cancer can contribute to this risk. These factors boil down to genetics.
People are more likely to develop colorectal cancer if they inherit particular gene mutations. While these mutations do not make cancer inevitable, they can create a significantly increased risk. Inheriting gene mutations that make individuals more susceptible to colorectal cancer and other cancers is referred to as Lynch syndrome.
If a person is diagnosed with Lynch syndrome, their parents, children, brothers, and sisters also have a 50 percent chance of developing the condition.
Most people with Lynch syndrome unaware they have the condition
Heather Hampel, principal investigator of Ohio Colorectal Cancer Prevention Initiative and licensed genetic counselor at the Ohio State University Comprehensive Cancer Center - Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, points out that most people who have Lynch syndrome are unaware that they have the condition.
"Lynch syndrome increases the risk for several types of cancer. The problem is 95 percent of those who have Lynch syndrome don't know they have it," says Hampel. "One of the keys to beating many types of cancer is catching it early, and the best way to do that is to know a patient's risk so we can monitor them closely and treat them at the first sign of trouble."
Researchers say that an estimated 639 years of life could be saved through early detection of colorectal cancer. In a bid to take preventive action, Hampel and colleagues screened 3,000 individuals who had been newly diagnosed with colorectal cancer and their at-risk family members to find out if they had Lynch syndrome.
"From that, we have actually offered genetic testing to about 370 at-risk relatives, and another 120 have tested positive, so you can see where it balloons once you get to the family members," reveals Hampel.
It has been estimated that about 1 in every 30 colorectal cancer cases are due to Lynch syndrome. People with Lynch syndrome are also at a higher risk of developing colorectal cancer at an earlier age - usually before age 50.
Early cancer detection based on genetic risk factors could save lives
Hampel and collaborators analyzed a subset of colorectal patients who have been diagnosed since 2013, and who are under the age of 50. The team found that 1 in every 6 of the subset had at least one genetic mutation that put them at an increased risk of colorectal cancer.
While the researchers expected a high rate of Lynch syndrome in the subset of colorectal patients under 50 years of age, surprisingly, they also found other gene mutations among the individuals, including mutations in genes typically linked to breast cancer. The findings were published in JAMA Oncology.
"The prevalence of hereditary cancer syndromes among early-onset colorectal cancer patients - including Lynch syndrome - was quite high, which represents a tremendous opportunity for us to save lives through early detection based on genomic risk factors. It is critical that people find out at a young age if they are genetically predisposed to cancer so they can take steps to prevent cancer from occurring at all."
"Knowledge truly is power in this case where if you know that you're at increased risk for something, you can take the steps needed to keep yourself from getting that cancer and prevent it," she adds.
People with Lynch syndrome can develop a cancer screening plan with their doctor to regularly screen for colorectal tumors. Finding and removing abnormal growths, or polyps, early can help to prevent colorectal cancer.
"We hope our efforts through the Ohio Colorectal Cancer Prevention Initiative will have applications nationwide," says Hampel. "In all, 50 hospitals in Ohio tested patients, all of whom were diagnosed with colorectal cancer under the age of 50."
"We hope to potentially expand to the region or to the nation. Really we believe all 50 states should be screening all of their newly diagnosed colorectal cancer patients for Lynch syndrome at the time of diagnosis," Hampel concludes.
The Ohio State University news release, accessed 15 December 2016.
CDC, Colorectal cancer statistics, accessed 15 December 2016.
CDC, Have you or a family member had colorectal cancer? accessed 15 December 2016.
Mayo Clinic, Colon cancer - Overview, accessed 15 December 2016.
Mayo Clinic, Lynch syndrome - Overview, accessed 15 December 2016.