The colon and rectum are both a part of the large intestine but they start in different places. The colon is about five feet long, and the rectum is the last six to 12 inches of the colon that extends to the anus.
Rectal cancer starts in the rectum, which is the last 12 centimeters (nearly 5 inches) of the colon. It’s where the body stores stools until you have a bowel movement. Colon cancer can begin anywhere in the colon, which is about five feet long and absorbs water from stool. Both cancers have very similar risk factors, symptoms and treatments.
Forty-five is the recommended age to begin colorectal to begin colorectal cancer screening, unless there is a family history, in which case screenings should start earlier. Other factors such as obesity, sedentary lifestyle, smoking and the amount of intake of red meat can all increase the risk of colorectal cancer. Some families are more colorectal cancer-prone than others due to genetic predisposition to colorectal cancer, referred to as Lynch syndrome. Through genetic testing, Lynch syndrome, often called hereditary nonpolyposis colorectal cancer, can be identified.
Possible symptoms of colorectal cancer may include a change in bowel habits, such as diarrhea, constipation, narrowing of the stool, that lasts for more than a few days, or a feeling that you need to have a bowel movement that is not relieved by doing so. Other symptoms may be rectal bleeding or blood in the stool, which may make it look dark, cramping or abdominal (belly) pain, weakness and fatigue, or unintended weight loss. Please consult with your doctor if you experience any of these symptoms.
Source: cancer.org