A colonoscopy serves as both a screening and a diagnostic medical procedure, allowing a gastroenterologist to visually examine the entire length of the large intestine, or colon. This examination uses a flexible tube equipped with a camera to look for abnormalities within the bowel lining. Finding a growth or lesion during this process is a relatively common occurrence. The ability to identify these findings early is the primary way a colonoscopy helps prevent colorectal cancer. Discovering something during the procedure is the beginning of a systematic process that determines the nature of the finding and establishes a plan for managing it.
Immediate Actions Taken During the Procedure
Upon the identification of any abnormal tissue, the gastroenterologist will take immediate action using specialized instruments passed through the colonoscope. The course of action depends largely on the appearance and size of the lesion. For the vast majority of growths, known as polyps, the goal is to remove them completely during the procedure in a process called a polypectomy.
Small to medium-sized polyps, typically under one centimeter, are removed using a wire loop, or snare, sometimes with an application of electrical current to cauterize the tissue base and prevent bleeding. Larger or flatter polyps may require a technique called Endoscopic Mucosal Resection (EMR). This involves injecting a fluid beneath the growth to lift it away from the colon wall, making the complete removal safer and more effective. The entire removed growth is then retrieved and sent to a pathology laboratory for detailed analysis.
If a lesion appears particularly large, deeply invasive, or has characteristics that suggest a high likelihood of malignancy, the approach shifts from complete removal to a targeted tissue biopsy. In these cases, the physician takes only a small sample of the tissue to confirm the diagnosis and determine the depth of any potential invasion before recommending a more extensive treatment plan. The immediate removal or biopsy during the colonoscopy is the first step in preventing cancer or diagnosing it early.
Understanding the Pathology Report
After the tissue sample is removed, it is sent to a laboratory where a pathologist examines it under a microscope, generating a report that dictates the next steps. This pathology report provides the definitive diagnosis by classifying the cells within the growth. One of the most common and important terms found is adenoma, which refers to a precancerous polyp that has the potential to develop into cancer over time.
Adenomas are further classified by their microscopic growth patterns, which affect their risk level.
- Tubular adenomas are the most common type and are generally considered lower risk.
- Villous adenomas or tubulovillous adenomas contain more complex structures and carry a higher risk of turning cancerous.
- Sessile serrated adenomas are often flatter, found in the right side of the colon, and represent a distinct pathway to cancer.
The term dysplasia describes how abnormal the cells look compared to healthy tissue, and it is crucial for determining risk. Polyps with low-grade dysplasia appear mildly abnormal and are considered a low-risk finding. Conversely, polyps showing high-grade dysplasia contain cells that are significantly more abnormal, classifying the finding as high-risk for progression. A diagnosis of carcinoma means the pathologist has confirmed the presence of cancer, specifically noting if it is confined to the polyp or has invaded deeper layers of the colon wall.
The report may also identify benign findings, such as hyperplastic polyps, which are non-neoplastic and carry a negligible risk of becoming cancerous. Understanding these terms allows the patient and physician to accurately assess the risk associated with the removed lesion.
Developing a Treatment and Surveillance Plan
The pathology report serves as the foundation for the long-term management strategy, establishing a plan for future monitoring and any necessary treatment.
For patients with low-risk findings, such as one or two small tubular adenomas with low-grade dysplasia, the surveillance interval is often extended. Current guidelines recommend a repeat colonoscopy in five to ten years for this low-risk group, similar to the interval for an average-risk screening.
A finding of high-risk characteristics triggers a much shorter surveillance timeline. Patients are typically advised to return for a surveillance colonoscopy in three years to ensure no new or recurring polyps have developed. High-risk characteristics include:
- Three or more adenomas.
- Any adenoma larger than one centimeter.
- A polyp with villous features.
- High-grade dysplasia.
Management of Carcinoma
If the pathology report confirms a diagnosis of invasive carcinoma, the management plan immediately shifts to a multidisciplinary approach involving several specialists. This team may include a colorectal surgeon and an oncologist to determine the extent of the cancer and the most effective treatment strategy. Treatment often involves surgery to remove the affected section of the colon, and may be followed by chemotherapy or radiation therapy, depending on the cancer’s stage. For patients who have had cancer removed, a follow-up colonoscopy is usually performed within one year to check the surgical site and the rest of the colon for recurrence or new growths.