What Are the Causes and Risk Factors for Colon Cancer vs. IBS?
Colon Cancer Causes and Risk Factors
Most colorectal cancers arise from adenomatous polyps. Such polyps are comprised of excess numbers of both normal and abnormal appearing cells in the glands covering the inner wall of the colon. Over time, these abnormal growths enlarge and ultimately degenerate to become adenocarcinomas.
People with certain genetic abnormalities develop what are known as familial adenomatous polyposis syndromes. Such people have a greater-than-normal risk of colorectal cancer. In these conditions, numerous adenomatous polyps develop in the colon, ultimately leading to colon cancer. There are specific genetic abnormalities found in the two main forms of familial adenomatous polyposis. The cancer usually occurs before age 40 years. Adenomatous polyposis syndromes tend to run in families. Such cases are referred to as familial adenomatous polyposis (FAP). Celecoxib (Celebrex) has been FDA approved for FAP. After six months, celecoxib reduced the mean number of rectal and colon polyps by 28% compared to placebo (sugar pill) 5%.
Another group of colon cancer syndromes, termed hereditary nonpolyposis colorectal cancer (HNPCC) syndromes, also runs in families (genetic, inherited). In these syndromes, colon cancer develops without the precursor polyps. HNPCC syndromes are associated with a genetic abnormality. This abnormality has been identified, and a test is available. People at risk can be identified through genetic screening. Once identified as carriers of the abnormal gene, these people require counseling and regular screening to detect precancerous and cancerous tumors. HNPCC syndromes are sometimes linked to tumors in other parts of the body.
Also at high risk for developing colon cancers are people with:
The risk of colon cancer increases two to three times for people with a first-degree relative (parent or sibling) with colon cancer. The risk increases more if you have more than one affected family member, especially if the cancer was diagnosed at a young age.
Other factors that may affect your risk of developing a colon cancer include:
- Diet: Whether diet plays a role in developing colon cancer remains under debate. The belief that a high-fiber, low-fat diet could help prevent colon cancer has been questioned. Studies do indicate that exercise and a diet rich in fruits and vegetables can help prevent colon cancer.
- Obesity: Obesity has been identified as a risk factor for colon cancer.
- Smoking: Cigarette smoking has been definitely linked to a higher risk for colon cancer.
- Drug effects: Recent studies have suggested postmenopausal hormone estrogen replacement therapy may reduce colorectal cancer risk by one-third. Patients with a certain gene that codes for high levels of a hormone called 15-PGDH may have their risk of colorectal cancer reduced by one-half with the use of aspirin.
Irritable Bowel Syndrome Causes and Risk Factors
The cause of irritable bowel syndrome is currently unknown. It is thought to result from a combination of abnormal gastrointestinal (GI) tract movements, increased awareness of bodily functions, and a disruption in the communication between the brain and the GI (digestive) tract.
Risk factors for IBS include:
- Abnormal (too fast or slow, or too strong) movements of the colon and small intestines
- Hypersensitivity to pain caused by gas or full bowels
- A viral or bacterial infection of the stomach and intestines (gastroenteritis)
- Small intestinal bacterial overgrowth (SIBO)
- Reproductive hormones or neurotransmitters may be off-balance in people with IBS.
Anxiety or depression may accompany IBS, though these have not been found to be a direct cause of IBS.