August 6, 2010
Dear Mayo Clinic:
I've heard of stents being used to treat heart disease, but recently I saw a news story that talked about using stents as an alternative to colostomy in people who have colon cancer. How does this work? Is it safe?
Although they are most often associated with treatment for heart disease, expandable metal tubes (stents) can be used for a variety of purposes, including opening up a blocked colon due to cancer. In some people with colon cancer, placing a stent may be a useful alternative to a temporary or permanent colostomy to relieve a blockage. Stent placement can also decrease the amount of surgery needed to treat the disease, in some cases.
Stents were initially developed to clear blockages in heart (coronary) arteries. They came to be used in the gastrointestinal tract, including the colon, later on. But the concept of stenting is the same, no matter where in the body stents are used. Stents are placed by threading a thin guide wire across a blockage, followed by passage of a catheter over the wire. A collapsed stent, which is loaded on the tip of the catheter, is passed over the wire and centered in the area of blockage. The stent is then released, allowing it to expand. This opens the blockage and keeps the area open.
Some people who have colon cancer experience blockage of the colon due to tumor growth. A blocked colon can cause serious illness and requires immediate treatment. Before stent placement was an option, these patients usually needed to undergo emergency surgery to divert the colon around the blockage and remove the tumor. Typically, that included creating a temporary colostomy — in which a portion of the colon is brought to the surface of the abdomen, and an opening (stoma) is created to allow stool to pass out of the body into a pouch that's attached to the skin. The colon could not be put back together during the same surgery because the colon above the blockage couldn't be cleansed prior to surgery. A second surgery at a later date was necessary to reattach the two ends of the colon, allowing for elimination of the colostomy.
Placing a stent rather than using emergency surgery to divert the colon provides a number of benefits. First, if successfully placed, the stent can reduce surgical risk and result in shorter recovery time for the patient. Second, it allows the colon to continue functioning, so that no colostomy is required. Third, surgery performed later to remove the tumor and the stent in one section of the colon may be done laparoscopically, again resulting in a quicker recovery.
The risk of complications associated with stent placement in people with colon cancer is low when the stent is placed by an experienced physician. In addition, research has compared the outcomes of colon cancer patients with complete blockage of the colon who had a stent placed followed by surgical removal of a tumor, to outcomes of a group of colon cancer patients who didn't have stents. Results showed no significant difference in cancer recurrence rates between the two groups. This suggests that using stents poses no greater risk of recurrence than other comparable treatment approaches for colon cancer.
Stent placement can also be helpful in people whose colon cancer has progressed to an advanced stage, when removing the tumor isn't an option. In such situations, placing a stent to relieve a blockage may help reduce a person's symptoms, avoid a permanent colostomy and improve quality of life. Stents can be used in a similar way for inoperable tumors that obstruct the esophagus, stomach or small intestine.
— Todd Baron, M.D., Gastroenterology, Mayo Clinic, Rochester, Minn.