Colon cancer is a significant health concern worldwide, ranking among the most common cancers and a leading cause of cancer-related deaths. Early detection plays a major role in achieving successful treatment outcomes, as the disease is often more manageable in its initial stages. Endoscopy, a medical procedure allowing doctors to visualize the inside of the body, has emerged as a primary tool for detecting and diagnosing colon cancer. It captures detailed images of the colon’s lining, providing direct visual evidence of any abnormalities.
The Role of Endoscopy in Colon Cancer Detection
A colonoscopy is a specific type of endoscopy that examines the large intestine, including the colon, rectum, and anus. During this procedure, a long, flexible tube called a colonoscope, equipped with a camera and a light, is inserted through the rectum. The colonoscope transmits images of the colon to a monitor, providing a clear view. To improve visibility, the tube inflates the bowel with air or carbon dioxide, expanding the colon.
Colonoscopy serves several purposes. It is widely used for screening, which involves looking for early signs of cancer, such as polyps. It also diagnoses suspicious symptoms such as changes in bowel habits, rectal bleeding, or abdominal discomfort. Additionally, it is used for surveillance in individuals with a higher risk of developing colon cancer, such as those with a personal history of polyps or inflammatory bowel disease.
Before a colonoscopy, patients undergo bowel cleansing preparation to ensure the colon is clear for optimal viewing. This preparation involves consuming a liquid that helps empty the bowel. During the procedure, patients are given a sedative to help them relax and minimize discomfort, though they may still experience pressure, bloating, or cramping. The procedure takes about 30 to 60 minutes, with additional time for preparation and recovery.
Interpreting Endoscopy Images of the Colon
During a colonoscopy, clinicians examine the images captured by the colonoscope for any deviations from a healthy colon lining. A healthy colon appears pink, smooth, and displays distinct, well-organized blood vessels. The surface should be uniform in texture.
In contrast, abnormal findings indicate areas of concern. Polyps are growths that protrude from the inner lining of the colon. Some polyps are “pedunculated,” meaning they have a stalk. Others are “sessile,” attaching to the lining with a broad base. Polyps can also be “flat” or slightly “depressed.”
Polyps are categorized into different types, such as hyperplastic polyps, which are harmless, and adenomatous polyps, which can develop into cancer if left untreated. Sessile serrated lesions also have a higher potential to become cancerous.
Early-stage colon cancer can present as subtle changes. These include slight alterations in color or texture, ulcerations, or irregular lumps. These early lesions may be difficult to distinguish and may require specialized imaging techniques to enhance visibility.
As colon cancer progresses, the signs become more apparent. Advanced cancer may appear as larger masses or tumors that project into the colon’s lumen. Ulcerated lesions, characterized by open sores on the lining, indicate advanced disease. A narrowing of the colon, known as a stricture, can also be a sign of an invasive tumor. While these images provide clues, a definitive diagnosis of cancer cannot be made from images alone; they only identify suspicious areas that warrant further investigation.
What Happens After Endoscopy
Following a colonoscopy, patients spend about an hour in a recovery area, allowing the effects of sedation to wear off. It is common to experience bloating or gas pains as air is cleared from the colon. Some individuals might also notice blood in their bowel movements, especially if polyps were removed or biopsies were taken. While generally safe, very rarely, a tear in the bowel wall can occur, which might require surgery.
If the endoscopist identifies any suspicious areas or polyps during the examination, tissue samples, known as biopsies, are collected. These samples are sent to a laboratory for examination by a pathologist, a doctor specializing in diagnosing diseases by studying tissues. The pathologist analyzes the cells to determine if they are benign (non-cancerous), precancerous (having the potential to become cancerous), or malignant (cancerous). This analysis is compiled into a pathology report, which becomes available.
Upon receiving the pathology report, the doctor will discuss the findings with the patient. If polyps were removed, the report will specify their type and whether they showed any precancerous changes. If cancer is confirmed, further tests might be ordered to determine the extent of the disease and its spread. Based on the results, follow-up actions can vary, ranging from surveillance colonoscopies at specific intervals to treatment planning, which may involve surgery, chemotherapy, or radiation therapy.