Who is at risk for colon cancer and how can you decrease your risk?
Updated: Sep 13, 2020
Can we decrease your risk of colon cancer?
Colorectal Cancer Risk Factors
Different cancers have different risk factors. Some risk factors, like smoking, can be changed; whereas others, like a person’s age or family history, can’t be changed. Realize that having a risk factor, or even many risk factors, does not mean that you will get colon cancer, and many people who get colon cancer do not have any known risk factors. Researchers have found several risk factors that might increase a person’s chance of developing colorectal polyps or colorectal cancer.
Colorectal cancer risk factors you can change:
Being overweight or obese:
If you are overweight or obese (very overweight), your risk of developing and dying from colorectal cancer is higher. Being overweight raises the risk of colon and rectal cancer in both men and women, but the link seems to be stronger in men. Getting to and staying at a healthy weight may help lower your risk. Not being physically active: If you're not physically active, you have a greater chance of developing colon cancer. Regular moderate to vigorous physical activity can help lower your risk.
Certain types of diets: A diet that's high in red meats (such as beef, pork, lamb, or liver) and processed meats (like hot dogs and some luncheon meats) raises your colorectal cancer risk. Cooking meats at very high temperatures (frying, broiling, or grilling) creates chemicals that might raise your cancer risk, although it’s not clear how much this might increase your colorectal cancer risk.
Having a low blood level of vitamin D may also increase your risk. Following a healthy eating pattern that includes plenty of fruits, vegetables, and whole grains, and that limits or avoids red and processed meats and sugary drinks probably lowers risk.
Smoking People who have smoked tobacco for a long time are more likely than non-smokers to develop and die from colorectal cancer. Smoking is a well-known cause of lung cancer, but it's linked to a lot of other cancers, too. If you smoke and want to know more about quitting, please talk to me or your primary care provider for help with this.
Alcohol use Colorectal cancer has been linked to moderate to heavy alcohol use. Even light-to-moderate alcohol intake has been associated with some risk. It is best not to drink alcohol. If people do drink alcohol, they should have no more than 2 drinks a day for men and 1 drink a day for women. This could have many health benefits, including a lower risk of many kinds of cancer.
Colorectal cancer risk factors you cannot change:
Being older Your risk of colorectal cancer goes up as you age. Younger adults can get it, but it's much more common after age 50. Colorectal cancer is rising among people who are younger than age 50 and the reason for this remains unclear.
A personal history of colorectal polyps or colorectal cancer If you have a history of adenomatous polyps (adenomas), you are at increased risk of developing colorectal cancer. This is especially true if the polyps are large, if there are many of them, or if any of them show dysplasia. If you've had colorectal cancer, even though it was completely removed, you are more likely to develop new cancers in other parts of the colon and rectum. The chances of this happening are greater if you had your first colorectal cancer when you were younger.
A personal history of inflammatory bowel disease. If you have inflammatory bowel disease (IBD), including either ulcerative colitis or Crohn’s disease, your risk of colorectal cancer is increased. IBD is a condition in which the colon is inflamed over a long period of time. People who have had IBD for many years, especially if untreated, often develop dysplasia. Dysplasia is a term used to describe cells in the lining of the colon or rectum that look abnormal, but are not cancer cells. They can change into cancer over time. If you have IBD, you will need to start getting screened for colorectal cancer when you are younger and be screened more often. Please note that inflammatory bowel disease is different from irritable bowel syndrome (IBS), which does not appear to increase your risk for colorectal cancer.
A family history of colorectal cancer or adenomatous polyps. It is important to note that most colorectal cancers are found in people without a family history of colorectal cancer. Still, as many as 1 in 3 people who develop colorectal cancer have other family members who have had it. People with a history of colorectal cancer in a first-degree relative (parent, sibling, or child) are at increased risk. The risk is even higher if that relative was diagnosed with cancer when they were younger than 50, or if more than one first-degree relative is affected. The reasons for the increased risk are not clear in all cases. Cancers can “run in the family” because of inherited genes, shared environmental factors, or some combination of these. Having family members who have had adenomatous polyps is also linked to a higher risk of colon cancer. (Adenomatous polyps are the kind of polyps that can become cancer.) If you have a family history of adenomatous polyps or colorectal cancer, talk with your primary care physician or me about the possible need to start screening before age 45. If you've had adenomatous polyps or colorectal cancer, it’s important to tell your close relatives so that they can pass along that information to their doctors and start screening at the right age.
Having an inherited syndrome About 5% of people who develop colorectal cancer have inherited gene changes (mutations) that cause family cancer syndromes and can lead to them getting the disease. The most common inherited syndromes linked with colorectal cancers are Lynch syndrome (hereditary non-polyposis colorectal cancer, or HNPCC) and familial adenomatous polyposis (FAP), but other rarer syndromes can increase colorectal cancer risk, too.
Your racial and ethnic background. African Americans have the highest colorectal cancer incidence and mortality rates of all racial groups in the US. The reasons for this are not fully understood. Jews of Eastern European descent (Ashkenazi Jews) have one of the highest colorectal cancer risks of any ethnic group in the world.
Having type 2 diabetes People with type 2 (usually non-insulin dependent) diabetes have an increased risk of colorectal cancer. Both type 2 diabetes and colorectal cancer share some of the same risk factors (such as being overweight and physical inactivity). But even after taking these factors into account, people with type 2 diabetes still have an increased risk. They also tend to have a less favorable prognosis (outlook) after diagnosis.
Factors with unclear effects on colorectal cancer risk:
Night shift work Some studies suggest working a night shift regularly might raise the risk of rectal cancer. This might be due to changes in levels of melatonin, a hormone that responds to changes in light. More research is needed.
Previous treatment for certain cancers Some studies have found that men who survive testicular cancer seem to have a higher rate of colorectal cancer and some other cancers. This might be because of the treatments they have received, such as radiation therapy. Several studies have suggested that men who had radiation therapy to treat prostate cancer might have a higher risk of rectal cancer because the rectum receives some radiation during treatment. Most of these studies are based on men treated in the 1980s and 1990s, when radiation treatments were less precise than they are today. The effect of more modern radiation methods on rectal cancer risk is not clear, but research continues to be done in this area.