March is National Colorectal Cancer Awareness Month. Why is this month so important? Because among men and women, colorectal cancer is the second leading cancer killer in the United States and 60% of these deaths could be prevented if everyone age 50 and older just had regular screening tests.
It is very simple: colorectal cancer screening saves lives. Here’s why:
- Colorectal cancer usually starts from polyps (growths that should not be there) that can develop into cancer.
- Screening tests can find polyps so they can be removed before they turn into cancer.
- Screening tests can find colorectal cancer early when the chance of being cured is higher.
It is recommended that all individuals aged 50 and over talk with their doctors about getting screened. However, some individuals are at increased risk for colorectal cancer due to their personal or family history. These individuals may benefit from earlier and more frequent screening as well as speaking with a genetic counselor. You may be at increased risk if:
- You have inflammatory bowel disease
- You or a close relative have had colorectal cancer or polyps
- You have a personal or family history of any of the following:
- Colorectal or uterine cancer that is diagnosed before age 50
- 2 or more separate colorectal cancers in the same person
- 3 or more blood related individuals with colon or uterine cancer
- Colorectal or uterine cancer and a family history of ovarian, stomach, small intestine, pancreatic, urinary tract cancers, brain tumors, sebaceous adenomas or keratocanthomas
- 10 or more gastrointestinal adenomas or hyperplastic polyps throughout a person’s lifetime
About 5% of all colorectal cancer diagnoses are hereditary and it has been proven that identifying these individuals decreases mortality and morbidity in their at-risk family members. For this reason, Porter Adventist Hospital screens all newly diagnosed colorectal cancers for the hereditary colorectal cancer syndrome called Lynch syndrome, which predisposes individuals to colorectal, uterine, ovarian, and other cancers. More information about the two most common hereditary colorectal cancer syndromes (Lynch syndrome and Familial Adenomatous Polyposis) is below.
Individuals who would like to learn more about their risk for colorectal cancer and what colorectal cancer screening is recommended for them should speak with their doctors, a gastroenterologist, or a genetic counselor. Visit http://1.usa.gov/z4SIan for more information. If you have a family history of colorectal cancer and would like to speak with a genetic counselor, call Porter’s genetic counselor (Melissa Gilstrap, MS, CGC) at 303-765-3923 for more information.
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Lynch syndrome
AKA: Hereditary Non-polyposis Colorectal Cancer
Mutations in a mismatch repair genes (MLH1, MSH2, MSH6, and PMS2) predispose individuals to colon, endometrial, ovarian, stomach, small intestine, hepatobiliary, renal pelvic, pancreatic, and other cancers. Tumors are typically characterized as having microsatellite instability (MSI-high) and demonstrate absence of one or more of mismatch repair proteins on immunohistochemistry (IHC). Individuals with mutations in MSH6 and PMS2 tend to have later ages of onset for cancer (many greater than age 50) than those with MLH1 and MSH2 mutations. MSI or IHC testing should be conducted on any available colon or endometrial tumor samples prior to proceeding with genetic testing.
Familial Adenomatous Polyposis syndrome (FAP)
Mutations in APC predispose individuals to colon cancer due to the development of 100s to 1,000s of precancerous colon polyps. Polyps and cancer of the gastric fundus and duodenum are common findings as well. Osteomas, thyroid cancer, dental anomalies, congenital hypertrophy of the retinal pigment epithelium (CHRPE), soft tissue tumors, desmoid tumors, and other cancers can also occur. Individuals with APC mutations can have variable severities of FAP: Classic FAP, Attenuated FAP, and Gardner syndrome. Virtually all individuals with untreated FAP will develop colon cancer in their lifetime.