A colonoscopy is a procedure that can help detect various diseases, particularly in the large intestine. Let's take a closer look at how the process can detect colon cancer.
A colonoscopy is a specific endoscopy performed on the lower digestive system. Similar to an endoscopy, a colonoscopy uses a tube-like instrument with a camera at the end.
What is the difference between a colonoscopy and an endoscopy?
As previously explained, a colonoscopy is an endoscope specifically designed to examine the lower digestive tract. The term "endoscopy" is more often used for procedures using similar instruments but aimed at examining the upper digestive tract. A colonoscopy is used to examine the interior of the large intestine, extending from the junction with the small intestine.
Meanwhile, an endoscope used to examine the inside of the stomach and the beginning of the small intestine is called an esophagoduodenoscopy (EGD), often abbreviated as gastroscopy. In other words, endoscopy is a major component of this procedure. The part of the body examined with this method determines the name of the procedure. For example, an examination of the large intestine or colon is called a colonoscopy. An examination of the stomach is called a gastroscopy.
Function of colonoscopy
A colonoscopy aims to examine the interior of the large intestine by capturing images using a camera. It can also be used to obtain samples for biopsy. Sampling during a colonoscopy is performed in some cases requiring further tissue examination.
A biopsy can be performed in cases of colon tumors, polyps, and inflammatory bowel conditions such as ulcerative colitis and Crohn's disease. Furthermore, a biopsy can be performed as a follow-up to therapy. In cases of colon tumors, a colonoscopy with biopsy can be performed to assess whether the tissue shows signs of malignancy or colon cancer, especially if other symptoms suggest colon cancer.
Symptoms of colon cancer
Before performing a colonoscopy, the doctor will perform a preliminary medical interview or history taking, a physical examination, and preliminary diagnostic tests. Patients with colon cancer typically present with significant unexplained weight loss, unexplained rectal bleeding, changes in bowel habits, changes in stool structure, and difficulty defecating or passing gas.
If there is a suspicion of colon tumor or a tendency towards cancer, for further supporting examinations such as laboratory examinations for tumor markers, especially those specifically for detecting colon cancer such as CEA (carcinoembryonic antigen), CA 19-9 and CA 125. Although it is not certain that an increase in the value of these tumor markers indicates colon cancer, this examination can be an initial screening process.
Colonoscopy with biopsy
Tissue obtained from a colonoscopy with a biopsy will be further examined by an anatomical pathologist. They will be assessed for signs of dysplasia or precancerous lesions. These conditions involve abnormal cell changes but are not yet cancerous. This requires further, regular evaluation.
Meanwhile, cells that test positive for cancer will be further assessed to determine the type and stage, thus determining the appropriate therapy, such as surgery, radiotherapy, chemotherapy, or targeted therapy. This will be considered by the treating surgical oncologist. Written by Dr. Valda Garcia. Reviewed by Dr. Ernest Eugene.
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