digestive disorders
Colorectal Cancer
Treatment of Colorectal Cancer
Surgery Sometimes chemotherapy, radiation therapy, or both In most cases of colon cancer, the cancerous segment of the intestine and any nearby lymph nodes are removed surgically, and the remaining ends of the intestine are joined. If the cancer has penetrated the wall of the large intestine and spread to a very limited number of nearby lymph nodes, chemotherapy after surgical removal of all visible cancer may lengthen survival time, although the effects of these treatments are often modest. For rectal cancer, the type of operation depends on how far the cancer is located from the anus and how deeply it has grown into the rectal wall. The complete removal of the rectum and anus means the person needs a permanent colostomy. A colostomy is a surgically created opening between the large intestine and the abdominal wall. The contents of the large intestine empty through the abdominal wall into a colostomy bag. If doctors can leave part of the rectum and the anus is intact, the colostomy may be temporary. After these tissues have had time to heal (over several months), another surgery can be done to rejoin the rectal stump to the end of the large intestine, and the colostomy can be closed. In a colostomy, the large intestine (colon) is cut. The healthy end of the large intestine, which is before the blockage, is brought to the skin surface through a surgically created opening in the abdominal wall. It is then stitched to the skin of the opening. Stool passes through the opening and into a disposable bag. The colostomy allows the remaining part of the large intestine to rest while the person recovers. After the person recovers from the surgery and the colon heals, the two ends can be reattached so that stool can pass normally. When rectal cancer has penetrated the rectal wall and spread to a very limited number of nearby lymph nodes, giving chemotherapy plus radiation therapy (see Combination Cancer Therapy ) before or after surgical removal of all visible cancer may lengthen survival time. When cancer has spread to lymph nodes far from the colon or rectum, to the lining of the abdominal cavity, or to other organs, the cancer cannot be cured by surgery alone. However, surgery is sometimes done to relieve any intestinal obstruction and ease symptoms. Chemotherapy with a single drug or combination of drugs may shrink the cancer and prolong life for several months. The doctor usually discusses end-of-life care with the person, the family, and other health care professionals (see Treatment Options at the End of Life ). Stage 0: Cancer is limited to the inner layer (lining) of the large intestine (colon) covering the polyp. Stage 1: Cancer spreads to the space between the inner layer and muscle layer of the large intestine. (This space contains blood vessels, nerves, and lymph vessels.) Stage 2: Cancer invades the muscle layer and outer layer of the colon. Stage 3: Cancer extends through the outer layer of the colon into nearby lymph nodes. Stage 4 (not shown): Cancer spreads to other organs, such as the liver, lungs, or ovaries, or to the lining of the abdominal cavity (peritoneum). When the cancer has spread (metastasized) only to the liver, doctors sometimes remove tumors surgically. Alternatively, doctors may inject chemotherapy drugs or radioactive beads directly into the artery supplying the liver with blood. A small pump inserted surgically beneath the skin or an external pump worn on a belt allows the person to be mobile during the treatment. This treatment may provide more benefit than ordinary chemotherapy, but more research is needed. Radiofrequency ablation, which uses high-frequency alternating electric current (AC current) to heat and destroy tissue, is an alternative therapy for selected people who have liver tumors. Also, radiation therapy focused on the tumors can be used for palliation (to help relieve symptoms without necessarily aiming for a cure). If the cancer is obstructing the colon in a person who cannot tolerate surgery because of poor health, doctors may try to relieve symptoms in other ways. One treatment involves shrinking the tumor with a probe that applies an electric current (electrocautery) or sometimes with a laser. Alternatively, doctors may use an expandable wire mesh tube (stent) to hold open the obstructed area. All of these treatments can be done through a colonoscope. Although the person often feels better for a while, these treatments do not lengthen survival time. After surgery, colonoscopy should be done within 1 year. A second colonoscopy should be done 3 years after that if no polyps or tumors are found. Thereafter, colonoscopy should be done every 5 years. Doctors also do a physical examination and blood tests such as a complete blood count, liver tests, and carcinoembryonic antigen level at regular intervals after surgery. Imaging tests ( Computed Tomography and Magnetic Resonance Imaging of the Digestive Tract ) are done every 6 to 12 months for 5 years. 