According to the American Cancer Society, colorectal cancer is the third most common cancer diagnosed in men and women in the United States (excluding skin cancer). Each year, there are 140,000 new cases of colon cancer and over 50,000 deaths from colon cancer in the U.S. Your lifetime risk of developing colorectal cancer is between four to five percent or about 1 in 22.
The good news is that most of these cancers can be avoided by good preventative care, and getting screened for colon cancer could save your life.
Formation of colon cancer
Scientists have learned that colon cancer is the end result of a series of mutations in genes in the lining cells of the colon. Several of these mutations have to occur in the same cell for cell growth to become uncontrolled, resulting in cancer.
This takes time.
The earliest mutations cause cells to lump up into small mounds, called polyps. These cells have lost some of the controls of cell growth, but have not acquired mutations that allow for invasion into the body. This means that if these polyps can be found and removed, the risk of developing colon cancer is much lower. It has been estimated that it takes five to 10 years for the average polyp to develop and turn into cancer. Therefore, it’s possible to remove the polyps before they go bad.
Who’s at risk?
In order to detect these polyps, physicians look for polyps in individuals at greatest risk for developing them. For most individuals, the risk becomes significantly higher by age 50, but the rate of colon cancer has been rising in younger age groups. African-Americans also reach that high level of risk slightly earlier.
Some individuals may also inherit mutations that promote the development of colon cancer from their parents, and so screening is advised 10 years before their relatives first developed polyps or cancer.
Anyone with a family history of colon cancer in a first-degree relative (parents, siblings or children) needs to begin screening early.
Several screening methods are available for detection of colon cancer. As a gastroenterologist, I generally recommend colonoscopy, a procedure in which a flexible tube is inserted into the colon allowing polyps to be identified and removed on the spot.
In average-risk individuals, a colonoscopy screening only needs to occur every 10 years if the examination was complete. Other alternatives to colonoscopy include annual screening with an immunologic test for blood in stools or screening stool for blood and genetic mutations every five years. If these alternative tests are positive, a colonoscopy must be performed to look for and remove polyps or early cancers.
Make time for your health
Many individuals say that they “don’t have time” to be screened, and it does take some effort. If you have a colonoscopy, the colon will need to be cleaned out as well as possible and you will probably miss a day of work for the procedure.
But consider the cost of not being screened and developing a colon cancer — you may lose years of life.
Maybe this story will convince you: I remember one patient who came to my office because of ‘traveler’s diarrhea’ that she had picked up overseas. She was otherwise in good health but was overdue for a colon cancer screening. I mentioned to her at the time of her visit that she should be screened when she was over her acute illness. She opted not to do this and came back five years later with another episode of ‘traveler’s diarrhea’ — this time with some blood in her stools. A colonoscopy revealed a large, invasive cancer. She received chemo-radiation treatment but developed metastatic disease which has required constant attention. Had she been screened when she initially came in, the whole issue of cancer might have been avoided and she could have looked forward to another 25 years of life.
Long story short, don’t play dice with colon cancer. Get screened.
Looking to get screened? Find a physician nearest you, here.
About the author
Lawrence Schiller, MD, is the Chair of the Institutional Review Boards for Human Subject Protection at Baylor Scott & White Research Institute in Dallas. He received his medical degree from Jefferson Medical College and has been in practice for more than 40 years.