Colon and Rectal Cancer: Screening, Diagnosis, and Treatment of a Bowel Malignancy

Colon and rectal cancer, collectively termed colorectal cancer, is the third most common type of cancer in the United States. It is estimated that, in 2017, close to 150,000 new cases of colorectal cancer will appear in the United States with approximately 50,000 deaths from the disease. Because of its high rate of incidence, efforts are being made to raise public awareness about colorectal cancer risk factors, screening, diagnosis, and treatment. Getting a colonoscopy is not a nice-ity, its a necessity.

Risk Factors

Colorectal cancer has been associated with various risk factors. For example, genetics play a large role in the development of colon cancer, because individuals with a personal or family history of colorectal cancer have a risk for developing future colorectal cancer. Hereditary conditions that lead to colorectal cancer, such as hereditary nonpolyposis colorectal cancer and familial adenomatous polyposis, and the inflammatory bowel conditions, Crohn’s disease and ulcerative colitis are also positive risk factors.

As for environmental risk factors, several have been proposed and evaluated. The prevention methods of a low-fat high-fiber diet and use of nonsteroidal anti-inflammatory drugs (NSAIDs) appear to prevent colon adenomas, but not necessarily malignant colorectal cancer like adenocarcinoma. However, removal of colonic polyps and, for women, use of estrogen and progesterone after menopause may reduce the risk of colorectal cancer.


Screening of colorectal cancer involves a combination of different methods. One is the fecal occult blood test (FOBT) in which a physician inserts a finger through the anus, wipes a stool sample onto a special test card, and applies a testing fluid to see if the sample contains blood. Although lower gastrointestinal bleeding has many causes, colon cancer is a major one and should not be missed. In addition to FOBT, the patient undergoes a procedure, usually colonoscopy, to evaluate the inside of the large intestine. Other methods of screening, such as virtual colonoscopy with computed tomography (CT), are under investigation. At this time, guidelines recommend colorectal cancer screening to begin at 50 years of age with FOBT done annually and colonoscopy performed every 10 years.


Patients whose colorectal cancer is symptomatic and not detected by screening may report noticeable rectal bleeding, change in bowel movements, intestinal obstruction, and abdominal pain. Further evaluation is performed with colonoscopy, barium enema, and CT to rule out metastatic colorectal cancer.


Surgery is the mainstay therapy for colon cancer, involving resection of the affected bowel segment or the entire colon if much of the colon is affected. Chemotherapy is an option for those with metastatic cancer. For patients with sole rectal cancer, radiation therapy may also be beneficial to minimize the risk of recurrence. The treatment regimen is tailored to the individual patient, based on factors such as the cancer stage and coexisting conditions that may limit treatment success.

Final Words

As with any online health information, the above should serve only for educational purposes. Those in need of additional information should consult a physician, especially as advances are made in colorectal cancer management.