Can people under 45 get colorectal cancer?
In general, it is very uncommon for younger people to get colorectal cancer if there is no family history and if the person is under 30.
However, there are two well-recognized hereditary syndromes in which cancer can develop in young people. The first is Familial Adenomatous Polyposis (FAP). This is a disease in which affected people develop hundreds to thousands of precancerous polyps in the colon. Unless the colon is removed, 100% of these patients will get colorectal cancer, usually by their late 30s.
The other disorder is Hereditary Non-Polyposis Colorectal Cancer (HNPCC). In this syndrome, cancers also occur early and develop from polyps. The disease also can present at a later age. The standard recommendation is colonoscopy in at-risk younger people of affected families beginning at age 25 and repeated every two years. Genetic testing may also be helpful.
See below for more information about hereditary syndromes that increase a person's risk for CRC.
In addition, recent studies have reported an increase in colorectal cancer (CRC) in people younger than 50 years of age (early-onset CRC), despite a decrease in the incidence of CRC in older individuals (late-onset CRC. Tumors from early-onset CRC patients tend to have certain characteristics, features and location within the colon. The reasons for this increase in CRC in younger people who do not have the two well-recognized hereditary syndromes are not well understood.
We do know that, even without one of the above syndromes, children of people who developed colon cancer at a young age are at higher risk for early colon cancers themselves. When discussing screening with your doctor, make sure to note the age at which any relative had their first polyp or when they developed cancer. This will help to determine at what age you should begin screening -- typically ten years earlier than the age at which your family member was diagnosed.
In addition, experts recommend that physicians keep this early-onset trend in mind when evaluating patients who report rectal bleeding or other symptoms that could indicate CRC.