Colorectal cancer is the uncontrolled growth of abnormal cells in the lining of the large intestine that begins as benign growth, called a polyp. Removing polyps is extremely effective in preventing the development of colorectal cancer.
Most polyps cause no symptoms at all, so people do not usually know they even have a polyp. Fortunately, it takes several years for a polyp to turn into cancer, which is why screening for polyps and cancer can be very helpful in preventing cancer.
If you have colorectal cancer, you are not alone. It is the third most common cancer. While it primarily occurs after the age 50, even those as young as 20-30 may develop the disease.
The most effective way to prevent colorectal cancer is early and regular screening, especially if you have any of the known risk factors.
Risk Factors for Colorectal Cancer
Several conditions are associated with increased risk of colorectal cancer. High risk factors include:
- Family history of polyps or colorectal cancer
- Genetic mutation in one of several genes associated with developing colorectal cancer: Lynch syndrome and familial polyposis.
- Inflammation of the colon (IBD)
- Personal history of having a polyp or colorectal cancer
All of these higher risk situations indicate that you should have frequent screenings, preferably with a colonoscopy.
While there is no known cause of colorectal polyps and cancer, a diet low in fiber, fruits, and vegetables, but high in animal fat and red, processed meat may be a contributing factor. Regular alcohol and cigarette use, and obesity are also risk factors.
Screening for Colorectal Cancer
There are several ways to screen for colorectal cancer and polyps. Colonoscopy is the gold standard. It allows your doctor to visualize the entire colon and rectum. If a polyp is found, it can be removed immediately. If a cancer is found, it can be sampled to confirm the diagnosis. Sigmoidoscopy is like colonoscopy but it only examines the lower half of the colorectal area. There is also CT colonography, known as a virtual colonoscopy that is performed by radiologists using a CT scanner. If a polyp or other growth is found during a CT colonography, a colonoscopy is then recommended to remove or sample the growth or lesion.
There are also at-home screening tests that require a sample of stool, which is then analyzed by the laboratory for traces of blood or abnormal genetic material. While a stool sample test is convenient, it is less accurate than colonoscopy or CT colonography. There are several types of these tests:
- A fecal immunochemical test (FIT): detects invisible traces of blood in the stool
- Fecal occult blood test (FOBT): a chemical test that detects traces of blood in the stool
- Cologuard: a new test that detects blood in the stool and also discovers the presence of any abnormal genetic material
If a stool-based test is positive, you should have a colonoscopy to determine if a polyp or cancer caused the positive test.
Screening is associated with a reduction in the incidence of colorectal cancer. You and your doctor can decide the appropriate screening option for you. The best test is the one that gets done.
Signs and Symptoms of Colorectal Cancer
Usually, colorectal cancer has no symptoms. However, you may develop symptoms of colon cancer such as:
- Abdominal pain or cramps,
- Black stool color
- Blood in the stool
- Changes in bowel habits
- Lack of appetite
- Unintentional weight loss
Diagnosing Colorectal Cancer
Your doctor will be able to make a diagnosis following a colonoscopy screening. Abnormal growths are removed completely or a sample is taken. In either case, the tissue is examined carefully under a microscope for your diagnosis.
In some cases, you may have a computed tomography (CT) scan that shows images of the entire abdominal cavity. It can show if abnormal tissue is present that will then be examined through a colonoscopy. The CT scan can also show if other organs are affected.
If during routine blood tests, you have a low blood count (anemia), your doctor may recommend a colonoscopy to see if the cause of the anemia is colorectal cancer.
Treatments We Offer
At Mount Sinai, we take a multidisciplinary approach to colorectal cancer treatment. You will receive care from a team of physicians, oncologists, surgeons, radiologists, nutritionists, and social workers who are dedicated to your care. Depending on the stage of your cancer, we treat colorectal cancer with surgery, chemotherapy, and radiation therapy.