Colon Cancer Screening
Colon cancer screening is one of the most important health maintenance topics. Based on large studies, colonoscopy and other methods of screening saves lives and helps prevent colon cancer related deaths. Here we provide a summary of general information on the topic.
What is Colon Cancer?
Colon cancer is one of the most common cancers. After excluding skin cancers, it is the third most common cancer in both males and females. It is estimated to have approximately 150 thousand cases between colon and rectal cancers. Moreover, it is expected to have about 50 thousand colon cancer related death in 2020.
What Causes Colon Cancer?
Colon cancer results from changes in the genetic structure of the cell, leading to an increase in cell growth or limited cell death. Those genetic changes can be new mutations during life, or inherited. The most common form is new mutations that we acquire during life. Usually cancer is not a result of single genetic issue, but the APC gene appears to be on of the common causes.
While most colon cancers are secondary to new genetic mutations during life, inherited gene mutations are well known.
Known genetic mutations that increase the risk of colon cancer:
- APC gene mutation: Familial Adenomatous Polyposis (FAP), Gardner Syndrome and Attenuated Familial Adenomatous Polyposis (AFAP)
- Mismatch repair genes including MLH1, MSH2, MLH3, MSH6, PMS1, and PMS2. This is the cause of Hereditary Nonpolyposis Colorectal Cancer (HNPCC) or Lynch syndrome.
- MYH gene: MYH Associated Polyposis or MAP.
These are some examples, however the important part of the above is that, while colon cancer can be associated with genetic predisposition, most colon cancers are a result from new mutations with no significant family history.
How to Prevent Colon Cancer?
As treatment of colon cancer is difficult, and many times require a combination of multiple treatment methods including surgery and chemotherapy, it is better to ask how to prevent it.
Scientists studied factors affecting risk of colon cancer, the following table summarizes factors associated with increased and decreased risk of cancer:
| Factors Considered Protective | Factors Associated With Increased Risk |
|---|---|
| High fiber diet | Alcohol consumption |
| Adequate calcium intake | Tobacco use |
| Adequate vitamin D intake | Red and processed meat consumption |
| Fish consumption | Obesity |
Physicians recommend multiple methods that help in the early diagnosis and prevention of colon cancer. The main categories are endoscopic visualization, radiographic testing and stool testing.
Methods of Colon Cancer Prevention and Early Diagnosis:
- Colonoscopy: This is the gold standard and the most sensitive testing for detection of polyps, early diagnosis and prevention of colon cancer. The added benefit is removal of polyps, which is the precancerous tissue before it becomes cancerous. Depending on various factors, we recommend colonoscopy for an average risk person without family history or personal history of colon cancer and polyps at 50 years of age, and earlier screening in certain populations. Age of colonoscopy will change depending on factors including family history, and suspicion of hereditary predisposition.
- Non invasive testing: This includes multiple stool tests and blood tests. Testing for blood in the stool on yearly basis is a screening alternative. Also, the multitarget stool DNA tests with fecal immunochemical testing is another alternative. The addition of DNA testing increases the detection of larger polyps and small cancers. However, this test does not detect small polyps very well.
- Imaging: There are multiple imaging modalities that can evaluate for colon cancer. Barium enema, and the more detailed CT colonography can provide valuable information in patients who had incomplete procedures, or sometimes as the initial screening method. The drawback is once abnormality is noted, a colonoscopy is recommended to evaluate the abnormality and sample the tissue or remove the polyp.
The information provided is general, and before making any decision make sure you discuss with your primary physician or us. If you have any questions or you want to schedule a colonoscopy you can request an appointment by clicking here.
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