Are you at high risk of developing large intestinal cancer?

We, doctors  have not found out what causes colon cancer. But the understanding of the sequential genetic damages that lead to cancer was formulated in Colon cancer. However, we know some of the risk factors that can lead to cancer. These risk factors can be habits, things in the environment, or genes that are passed down from parents to children . If one or more risk factors apply to you, it does not mean you’ll get colon cancer, but only that you will need closer observation than the rest of the people.

Please understand that colon cancer occurs in some people who have no known risk factors.

The following blog discusses the risk factors for large bowel cancer.

Older age - As you age, your risk for colon cancer increases . In fact, 90 % of patients with colon cancer are diagnosed at age 50 or older. The average age of all people diagnosed with colon cancer is above 65 years of age.

Family history of large intestinal cancer - Family history is the most important risk factor for colon
cancer. If a close blood relative has been diagnosed with colon cancer, you’re at risk. Your risk is even higher if your relative had cancer at a young age or if multiple relatives have had colon cancer.

Prior cancer in the same patient - You may have had surgery for colon cancer before. Even if all the cancer was removed, your chances of forming  new adenomas are higher than someone without prior colon cancer. You are also at risk for the return of colon cancer.

Some people with other cancers have a high risk for colon cancer. The higher risk is because of a genetic
condition that causes both cancers. Examples of cancers linked with colon cancer because of a genetic
condition are endometrial, uterine, pancreatic, and ovarian cancers.

Colon polyps - Polyps simply are projections in the lining of the large intestine. Not all polyps are the same. They all grow from the mucosa, but they differ in size, shape, and how their cells look. The odds of cancer forming in polyps differs by the type of polyp. There are three types of colon polyps, but you must understand that only one of them has a risk of colon cancer - It is the adenomatous polyp. This is detected only by microscope. So we remove all the polyp and send it for microscopic examination.

Adenomatous polyps, or adenomas, have cells that don’t look like normal colon cells. Most do not become cancerous, but most polyps with cancer started as adenomas. Your risk for cancer forming in adenomas is high if 3 or more adenomas are found, the adenomas are bigger than 1 cm, and the adenomas called villous adenomas.

Genetic conditions

Some genetic conditions are known to increase the odds of getting colon cancer. Lynch syndrome is the most common type of genetic condition to cause colon cancer. Even so, only 2 out of 100 people with colon cancer have Lynch syndrome. Familial adenomatous polyposis is a rare genetic condition that often leads to colon cancer by age 40. It starts with hundreds of polyps forming in the colon and rectum. A third genetic condition linked to colon cancer is MYH-associated polyposis. This condition also causes many polyps to form.

What I tell my patients is that the certain risks are modifiable. The most important modifiable risk factor is the polyp. This is the happiest news about a colon cancer risk. The detection and removal of polyps in the colon reduces the risk of death from colon cancer. This is based on the wonderful work on cancer formation by Dr. Fearon and Dr. Vogelstein and this spawned the research on the models for cancer formation.

The most important aspect is that you should understand your risk and reach out to your gastroenterologist for screening for cancer detection. That is the best thing you would do to your own self in gaining victory over colon cancer.