Sigmoid Colon Cancer

Submitted by Nic on October 19, 2012

The last part of the colon, which connects the descending colon to the rectum, is known as the sigmoid colon. All fecal matter is stored in this S-shaped part of the colon before it is expelled. When cancer cells are present in the lining of the sigmoid colon, it is termed as sigmoid colon cancer.

Sigmoid colon cancer can be divided into three separate stages, depending on how far the cancer has spread.

  • Stage 1: Presence of small tumors (polyps) in the sigmoid colon that have not yet reached the mucosal layer of the colon.
  • Stage 2: Cancer has spread to the mucosal layer.
  • Stage 3: Cancer has spread beyond the mucosal layer and affected nearby lymph nodes as well.

Risk Factors

Factors that put you at a higher risk of developing sigmoid colon cancer (or colon cancer) include:

  • Low fiber diet
  • Ulcerative colitis
  • Crohn’s disease
  • Presence of intestinal polyps
  • Excessive drinking/smoking
  • Family history of cancer

Symptoms and Diagnosis

Similar to colon cancer in general, there are no specific signs and symptoms in the earlier stages. Some non-specific symptoms do begin to manifest toward the later stages. If you experience any of the following, you should consult your doctor and get tested.

  • Diarrhea
  • Blood in your stool
  • Smaller or narrower stool
  • Abdominal pain or discomfort
  • Anemia
  • Sudden weight loss

A sigmoidoscopy is the standard procedure with which a doctor will check the inside of the sigmoid colon and rectum. If polyps are found, the tissue will be sent for testing in order to confirm whether the polyps are benign or cancerous.


If the polyps are found to be cancerous, a colonoscopy may be performed to check whether there are polyps in other parts of the colon.

Depending on the spread of the cancer; treatment may include surgery, chemotherapy, radiation, or all three.

In the earlier stages of the cancer, only surgery is necessary; however, in latter stages (stage 3) of the cancer, chemotherapy or radiation or a combination of the two will be required after surgery to kill the remaining cancer cells. In stage 1 of the cancer, a simple polypectomy to remove the polyps may be all that is required. In other stages, surgery for sigmoid colon cancer will include removal of all or part of the sigmoid colon as well as the surrounding lymph nodes if they are affected. The surgeon will connect the descending colon directly to the rectum if the entire sigmoid is removed.

If the cancer has spread to the rectum or anus, surgery options include:

  • Proctosigmoidectomy, where the diseased section of the rectum and sigmoid colon are both removed.
  • Abdominoperineal resection, where the anus, rectum, and sigmoid colon are all removed.


Prognosis of sigmoid colon cancer will depend on the stage at which your cancer was when you were diagnosed. If detected in the earlier stages, chances of survival are high, and if the cancer does not return after five years, following treatment, the patient is said to have recovered completely. However, in most cases, the cancer is detected at later stages when the symptoms begin to manifest. The five year sigmoid colon cancer survival rate is 62%, albeit this will vary depending on the stage in which the cancer is diagnosed. Survival rates for stage 4 colon cancer are as low as 8%.


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