What a perfect time to heighten our understanding of colorectal cancer
Colorectal cancer (CRC) is the third most common diagnosed cancer as well as the third leading cause of cancer deaths in the United States and in Minnesota. CRC is preventable.
Signs and symptoms of CRC include change in bowel habits (diarrhea, constipation, or narrowing of the stools lasting several days); incomplete emptying; rectal bleeding or blood within the stool (bright red blood or maroon or dark stool); abdominal cramping or pain; weakness or fatigue (anemia); and weight loss.
CRC develops slowly over the course of years; 95 percent begin as precancerous polyps inside the colon or rectum. Polyps can grow from the inside of the colon or rectal wall, through the layers of the colon, and eventually to nearby lymph nodes and other organs.
CRC is staged based on the TNM classification: T (depth of tumor penetration through the colon wall), N (lymph node involvement), and M (metastasis or distant spread of cancer outside of the colon).
CRC diagnosis is made by biopsy, and its subsequent staging is determined after obtaining CT scan of the chest, abdomen and pelvis. Overall five-year survival is excellent for early CRC (90 percent for Stage 1, 80 percent for Stage 2, 70 percent for Stage 3, and 14 percent for Stage 4).
Risk factors include:
1) age (risk increases with age, as 90 percent of CRC diagnosed among people 50 years or older);
2) male gender (CRC incidence is greater for men than women);
3) personal history of colon polyps or cancer;
4) family history of colon cancer and genetic syndromes (Familial Adenomatous Polyposis or Lynch Syndrome); and
5) inflammatory bowel disease (IBD), such as ulcerative colitis or Crohn’s disease.
Obesity, physical inactivity, smoking, heavy alcohol use, and diet high in red and processed meats have also been linked to CRC risk.
Importance of screening
There is strong evidence that the most effective prevention of CRC in average risk individuals is screening. Historically, guidelines have recommended screening begin at age 50 in the average risk population.
For unknown reasons, CRC incidence and mortality have been increasing in individuals aged 20-49, especially in the African American population. Consequently, new guidance recommends CRC screening in all average-risk individuals at age 45.
It is important to note that African Americans are more likely to die from CRC when compared to other races/ethnicities. In Minnesota, incidence and mortality are highest for American Indians (63 percent), followed by African Americans (40 percent), then Hispanics and Caucasians (39 percent each).
Screening guidelines for the average risk population have been published by several organizations with these recommendations: Start at age 45; stop at age 75; individualize at ages 76-85. Criteria for screening in the older age group is individualized based on patient preference, life expectancy, overall health and prior screening history.
For those at increased or high risk, referring to the factors discussed above, screening guidelines generally recommend:
- If family history of CRC, begin screening at age 45 or 10 years earlier than family member diagnosed with CRC.
- If family history of familial or genetic syndrome, begin screening in teenage years or early 20s, with surveillance colonoscopy recommended every two years after initial examination.
- If polyps are found on initial colonoscopy, surveillance examination should be scheduled in one, three or five years depending on size, type and number of polyps.
- If you have a personal history of IBD, initial colonoscopy is recommended eight years after IBD diagnosis with surveillance examination every one to two years, depending on risk factors and findings on prior colonoscopy.
- Inflammatory bowel disease (IBD), such as ulcerative colitis or Crohn’s disease.
Screening tests are divided into two types:
Direct visualization | Stool tests* |
---|---|
Colonoscopy every 10 years | Fecal immunohistochemical test (FIT) yearly |
CT colonography (virtual colonoscopy) every 5 years* | Guaiac-based fecal occult blood test (gFOBT) yearly |
Flexible sigmoidoscopy every 5 years* | Multi-target stool DNA test (Cologuard) every 3 years |
*Any abnormal test should be followed with colonoscopy.
If you have any questions regarding your risk of CRC, please talk with a healthcare provider such as myself to discuss your best screening option. Please remember and always keep in mind, the best screening test is the one that gets done.
Sharon Luster Dykes, MD, FACS, FASCRS is a dual board certified colon and rectal surgeon,who received her Bachelor’s Degree as well as her medical degree from Brown University in Providence, RI, in 1988 and 1991, respectively. She has practiced colon and rectal surgery in the Twin Cities of Minnesota since 2003. In 2010 she launched her solo, independent surgical practice and serves as CEO of Minnesota Colon and Rectal Surgical Specialists.
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