Final answer:
A colonoscopy is a medical procedure used for the diagnosis and prevention of colorectal cancer by detecting and removing polyps. Alternative methods like flexible sigmoidoscopy, virtual colonoscopy, and noninvasive DNA stool tests serve as preliminary screening tools. Diagnosis and potential therapeutics are conducted using an endoscope for direct visualization of the colon.
Step-by-step explanation:
A colonoscopy is a medical procedure that allows a doctor to inspect the lining of the large intestine for any abnormalities such as cancerous lesions or polyps. Polyps are benign mucosal growths that can develop into cancer if left untreated; therefore, colonoscopy serves as both a diagnostic and a preventive measure against colorectal cancer. In cases where a full colonoscopy isn't performed, a flexible sigmoidoscopy can inspect the rectum and lower third of the colon, where the majority of colorectal cancers occur. However, this procedure does not allow examination of the rest of the colon. An alternative is a virtual colonoscopy, which uses CT scans to create detailed images of the colon and rectum for analysis by a specialist. If polyps or cancerous lesions are detected, a follow-up colonoscopy is necessary. Another noninvasive test involves analyzing a stool sample for DNA from cancer cells, and if the test is positive, a colonoscopy is required.Besides aiding in detection, a colonoscopy can prevent colorectal cancer by enabling the removal of precancerous polyps. During the procedure, an endoscope—a tube with a tiny camera—is inserted into the colon to visualize the area and potentially remove polyps using surgical instruments that can be inserted through the scope. Symptoms that may signal colorectal cancer include constipation or diarrhea, abdominal pain, and rectal bleeding. Screening methods such as fecal occult blood tests and colonoscopies are recommended for individuals over 50 years of age.The colon is an integral part of the large intestine, specifically the section between the small intestine and rectum responsible for absorbing water and salts from liquid food wastes to form feces. The use of an endoscope to look inside the body is not limited to colonoscopies; it is a common tool in various medical procedures with capabilities for both diagnosis and therapeutic interventions. Endoscopes can transmit images to an eyepiece or video screen and accommodate surgical instruments for procedures such as biopsies and polyp removal.