A polyp is a general term used for any growth that might be benign. A precancerous polyp by itself is not malignant but if left untreated can become cancerous. It is very common for adults to have polyps in their colon. Precancerous lesions can usually be surgically extracted to avoid cancer. There are two types of polyps hyperplastic polyps and adenomatous polyps.
Hyperplastic polyps are benign and non-cancerous growths. They are small and usually found in the rectum and are not cancerous. Similarly hyperplastic polyps can also be found in the right side of the colon. These polyps pose a risk of cancer. These are treated as precancerous lesions and removed to prevent the spread of cancer.
Adenomatous polyps are precancerous polyps which cannot be left untreated. These are usually found in the inside lining of the colon and have high potential of becoming cancerous if not removed. Adenomatous polyps are of two types’ tubular adenomas and villous adenomas. Tubular adenomas are common and can become villous adenomas which are cancerous. Villous adenomas are serious and have a very high risk of becoming cancerous. People having villous adenomas have to be screened frequently for colon cancer.
Some polyps with abnormal cells are also called dysplasia. They can be high grade or low grade dyplasia depending on the severity of them turning into cancer.
Stages of a precancerous polyp progressing to cancer
The symptoms mentioned below are that of precancerous symptoms of colorectal cancer.
Medical history and physical exam
The individual is examined for a personal and family history of inflammatory bowel disease, colorectal cancer and hereditary non-polyposis carcinoma. A digital rectal examination (DRE) checks for abnormalities in the rectum or prostate.
This is a CT scan which creates images of the colon without inserting an endoscope.
It presents three dimensional and cross section images of the organs and is useful to check the spread of cancer to other body parts.
The CT scan helps to guide the needle to perform a biopsy and presence of precancerous cells in a tumor. The suspected tissues are removed and examined under the microscope for malignancy.
Blood chemistry tests
Urea and liver enzymes tests help measure chemicals in the blood and the level at which the colorectal cancer is staged. Higher levels of chemicals are indicative of the cancer having spread to the kidney and liver.
Flexible sigmoidoscopy and colonoscopy
Both tests enable to view the lining of the rectum and colon, respectively for the presence of polyps in the area. If they are found, they are removed and biopsied.
Precancerous Polyps treatment
small polyps can be left alone and can be observed periodically. Large polyps (> 1cm) will require endoscopic removal.