The large intestine is the continuation of the small intestine and is a high-capacity tube that extends from the cecum to the anus (including the rectum). The large intestine consists of the cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, and anus.
Colon and rectal cancer is the most common malignant disease of the digestive system and is the second most frequent and deadly after lung cancer. It can occur at any age, with higher frequency after the fifth decade of life. Its frequency increases with age, and it affects both genders.
Colonoscopy is the preferred examination for screening the large intestine in both symptomatic and asymptomatic patients. It detects all lesions along the colon and offers the possibility of polypectomy and biopsy sampling. It is important to examine the entire length of the colon to identify possible simultaneous lesions, and if malignant obstruction prevents preoperative colonoscopy, it should be performed later.
Once the diagnosis of colon cancer is made, the patient must undergo imaging to assess the extent of the disease (both local and distant) to determine the appropriate treatment and prognosis. Preoperative clinical staging is done through physical examination (looking for ascites, hepatomegaly, checking for lymphadenopathy, and digital rectal examination for rectal cancer), as well as abdominal-pelvic and chest CT scans.