Would a routine colonoscopy prevent colon cancer if done every 10 years, since this type of cancer grows so slowly and usually starts as a benign polyp?
The colonoscopy is a marvel of medical technology that allows physicians to detect precancerous growths in the large colon called polyps.
Knowing that colon cancer can take years to develop (and hence why a routine colonoscopy is recommended for average-risk people every 10 years beginning at age 50), I wondered if, in a 50-year-old who has a clean colonoscopy, could colon cancer be prevented if he or she continues having colonoscopies every 10 years; after all, how quickly can a polyp form and morph into a malignancy between 10-year screenings?
“First, there are outliers in terms of age of cancer development; some sporadic cases in their 20s or 30s,” begins Whitney Jones, MD, Clinical Professor of Medicine, University of Louisville, and Founder, Colon Cancer Prevention Project.
“The 40-year age group is a different question altogether.”
Thus, the question pertains strictly to average-risk (of colon cancer) people who begin having the routine colonoscopy.
Unless there is a family or personal history of colon cancer, a person will not be advised to begin colonoscopy screening until age 50.
Dr. Jones continues, “Second, there are outliers in terms of the biological behavior and rapidity of growth of the classic polyp-to-cancer sequence that have aggressive growth, resulting in cancer in small growths that evidently turn into cancer, and may even spread to blood vessels and lymph nodes while being very small (i.e., sub 1 centimeter).”
Finally, Dr. Jones explains that there are technical issues. He says, “All cancer screening tests are by their nature imperfect:
“Polyps are missed (up to 10-15 percent); blind spots for the endoscopist in the colon are a reality despite evolving technology; preps are not always optimal; there are significant performance differences between individuals who perform colonoscopy.
“Standardized preps including split dose preps, withdrawal time tracking and adenoma detection-rate tracking are helping endoscopists improve on this third and important variable.”
Despite the “imperfect” nature of the colonoscopy, it’s a glaring fact that the number of people who avoid colon cancer screening via colonoscopy is directly related to the mortality rates of this disease.
By the time symptoms first start presenting (e.g., change in bowel habits, change in stool caliber, diarrhea, blood in stools, ribbon-like or pencil-thin stools, abdominal pain, nausea, vomiting, fatigue, unexplained weight loss, constipation — especially if it alternates with diarrhea), the malignancy has likely already spread beyond the large colon and even into surrounding organs.
Thus, routine colonoscopies are life-saving and make a tremendous difference in the development and survival rates of colon cancer.
Note: If you have any of the above symptoms, don’t jump to the conclusion it must be a malignancy.
The above symptoms are common and can be explained by many benign gastrointestinal disorders.
However, if symptoms haven’t resolved within two weeks, see a gastroenterologist — with the exception of bloody or “tarry” stools: In that case, make an appointment ASAP.