Colorectal cancer refers to malignancies that originate in the rectum or the colon. It is also known as bowel cancer. Formation of adenocarcinomas is the most common feature of colorectal cancer. The cancer starts as a polyp in the inner wall of the colon or rectum. These polyps can be benign or malignant. Some of the risk factors that can cause colorectal cancer are lifestyle changes, old age, genetic disorders, family history, and inflammatory bowel disease. Some of the symptoms of colorectal cancer are blood in stool, decrease in appetite, constipation, weight loss, nausea, bloating, and pelvic pain. Colorectal cancer can be classified into four broad stages. Colorectal cancer can be treated using surgical, chemotherapeutic, biologic, and radiation therapies.