Colon cancer: these modifiable factors to reduce the risk
Some of the causes and risk factors for colon cancer can be easily modified to reduce the risk of developing the disease.
Some of the causes and risk factors for colon cancer, such as family history of the disease, are not within your control. But a surprising number of them are.
Scientists are still trying to understand why healthy cells in the colon and rectum become cancerous, growing and spreading out of control. But researchers know that colorectal cancer is the result of damage to a cell's DNA, leading to genetic changes called mutations.
A small percentage of mutations capable of causing colorectal cancer are hereditary, that is, passed down in families. Most, however, are acquired, meaning they develop over the course of a person's life, usually due to environmental or lifestyle factors. For the majority of people who develop colorectal cancer, there is no single genetic pathway to the disease. Scientists are working to better understand the complex interplay of factors that cause this cancer.
Hereditary causes of colon cancer
A small number of people inherit genetic mutations from their families that significantly increase their risk of colorectal cancer. They generally develop certain syndromes (sets of symptoms) linked to this genetic inheritance.
These include:
Familial adenomatous polyposis (FAP), attenuated FAP (AFAP) and Gardner syndrome
These conditions are directly linked to the inheritance of a mutated APC gene. When functioning properly, APC serves as a brake on cell growth. When mutated, it becomes part of a biochemical chain reaction that leads to the formation of hundreds of polyps in the colon, which can become cancerous.
Lynch syndrome (hereditary non-polyposis colon cancer)
It is a hereditary cancer syndrome that increases the risk of many cancers, including colorectal cancer. Mutations usually occur in the MLH1, MSH2, MSH6, PMS2 or EPCAM genes. These genes are involved in DNA repair. When mutated, they are unable to prevent mutations that can lead to cancer.
Peutz-Jeghers syndrome
Mutations in the STK11 gene (also called LKB1) cause most cases of this syndrome. When not mutated, this gene prevents cells from growing rapidly and uncontrollably. Uncontrolled growth, in this case, leads to colorectal polyps which can become cancerous.
Colon Cancer Risk Factors You Can't Control
Some colon cancer risk factors are not within your control. This list includes:
— Age
Although an increasing number of people are being diagnosed with early-onset colorectal cancer, the majority of people with the disease are over the age of 50.
– Personal or family history
If you have had colorectal polyps (abnormal growths in the colon or rectum), you are more likely to develop colorectal cancer. This is especially true if the polyps are large, multiple, or contain cells with noncancerous abnormalities (dysplasia).
– A family history of colorectal cancer is another risk factor. One in three people diagnosed with colon or rectal cancer have family members with the disease.
– Having had colorectal cancer increases the risk of recurrence, even if you were treated successfully the first time.
– Personal history of inflammatory bowel disease (IBD)
Inflammatory bowel diseases, which include Crohn's disease and ulcerative colitis, cause chronic inflammation of the colon. This can lead to dysplasia, which can eventually become cancer.
- Type 2 diabetes
People with this form of non-insulin-dependent diabetes not only have a higher risk of colon cancer and rectal cancer, but also tend to have a poorer prognosis after diagnosis.
Risk factors within your control
There are some risk factors for colorectal cancer that you can modify (at least in theory). These include:
Overweight
Men and women who are overweight or obese face an increased risk of colorectal cancer. Men, especially those who accumulate extra pounds around their waist, are most vulnerable.
Increasing rates of colorectal cancer among young people could also be due to increasing obesity rates. A study published in JAMA Oncology in 2018 tracked the health of more than 85,000 women for 22 years and found that the higher a woman's body mass index (BMI), the greater the risk of developing colorectal cancer before age 50 is important.
The study found that women ages 20 to 49 who were considered overweight or obese were up to twice as likely to develop early-onset colorectal cancer as women who reported the lowest BMIs .
Sedentary lifestyle
There is a strong body of evidence linking a sedentary lifestyle to an increased risk of colorectal cancer and rectal cancer. A meta-analysis of 28 studies, published in the journal Medicine in 2017, found a statistically significant association between daily sedentary time, specifically, watching television, and colorectal cancer risk.
The study also found that people who had jobs requiring prolonged sitting were more likely to develop colorectal cancer.
Researchers found that each two-hour increase in daily TV time increased the risk of colorectal cancer by 7%; two additional hours of work-related sitting resulted in a 4% increase.
A diet rich in meat
A diet high in red meat and processed meat has been linked to an increased risk of colorectal cancer. IARC, the cancer agency of the World Health Organization, has gone so far as to label processed meat a carcinogen and red meat a probable carcinogen. Twenty-two experts from ten countries reviewed more than 800 studies to reach these conclusions. They found that eating 50 grams of processed meat daily, the equivalent of about four strips of bacon or a hot dog, increased the risk of colorectal cancer by 18%.
Alcohol and tobacco
Researchers have linked moderate or heavy alcohol consumption to an increased risk of colon and rectal cancer. Evidence for this link is generally stronger in men than women, but studies have found a link between both sexes.
Smoking Most people know that smoking increases the risk of lung cancer, but it is less well known that it also increases the risk of colorectal cancer.