gastrointestinal disorders
Colorectal Cancer
Introduction
Colorectal cancer is extremely common. Symptoms include blood in the stool and change in bowel habits. Diagnosis is by colonoscopy. Treatment is surgical resection and chemotherapy for nodal involvement. Behavioral measures and possibly low-doseaspirinmay decrease risk. Colorectal cancer is the 4th most commonly diagnosed cancer in the United States. Incidence rises sharply around age 40 to 50. In 2023, an estimated 106,970 new cases of colon cancer and 46,050 new cases of rectal cancer will be diagnosed ( General references ). The number of colorectal cancer deaths has steadily decreased in the last several decades and is believed to be the result of improved screening and diagnosis at earlier stages of disease. Overall, more than half of the cases occur in the rectum and sigmoid, and 95% are adenocarcinomas. Colorectal cancer is slightly more common among men than women. Synchronous cancers (more than one) occur in about 5% of patients ( General references ). 