Colon Cancer

Treatment

Surgery is the primary treatment for most patients with colon cancer. Chemotherapy and radiation therapy are often combined with surgery in patients whose initial cancer has an increased risk of relapse if treated with surgery alone, such as when the tumor extends beyond the colon wall or lymph nodes are involved. These combined treatments may also be indicated for patients with cancer relapse at the local site or in nearby lymph nodes after initial treatment. Physicians also use biologic therapy, which uses the body's immune system to combat cancer.

Mayo Clinic offers several procedures for colon cancer that may not be widely available. These include minimally invasive (laparoscopic) surgery, intraoperative radiation therapy, colostomy-sparing surgery and treatments for synchronous tumors (those that have spread from the colon to other organs).

Treatment Team

Highly trained and experienced specialists from Gastroenterology, Surgery, Radiation Oncology, Medical Oncology, Radiology, Pathology and Medical Genetics work together to determine the most appropriate treatment for each patient. Mayo Clinic in Rochester, Minnesota ranked No. 1 among U.S. hospitals in the specialty of digestive disorders in the 2008 U.S. News Best Hospitals ranking.

Surgery

Once the health care team has pinpointed the location of the cancer, the surgeon may remove that section of the colon and reattach remaining sections to preserve function. A common treatment is open colectomy, in which the cancerous part of the colon is removed using standard surgery. In some cases, removal of part of the colon may be necessary, and the patient may be required to undergo a colostomy. This procedure allows waste to be expelled into a small bag worn externally.

Surgery gives physicians a clearer picture of the location and nature of the cancer, and the potential effectiveness of other treatments, including chemotherapy and radiation. Mayo Clinic's unique practice of immediately freezing and analyzing tissue samples taken during surgery helps surgeons remove as much of the cancer as possible. In some cases, this can avert the need for a second surgery. For most traditional colon surgeries, patients remain in the hospital for five to eight days. It usually takes about six more weeks at home to recover from the surgery.

The surgeon may remove the cancer using one of the following surgical procedures:

• Local excision: Surgeons remove only the cancer and some surrounding normal tissue.
• Anterior resection: Surgeons remove the cancer, some surrounding normal tissue including some uninvolved normal colon above and below the cancer, and lymph nodes. The colon is reconnected.
• Low anterior resection: Surgeons remove the cancer in the lower sigmoid colon, some surrounding normal tissue and lymph nodes. The colon is connected to the lower rectum.
• Abdominal perineal resection: When the cancer is located very close to the anal opening, the entire rectum and anus must be removed, making necessary a colostomy. Surgeons make an opening in the abdomen wall, and body wastes are eliminated through the colostomy into a special bag.
• Extended resection: When a locally advanced cancer penetrates the colon wall and invades other organs such as the pelvic or abdominal sidewall, vagina or bladder, surgical removal is extensive and is coordinated with radiation (external and intraoperative) and chemotherapy. In most instances the external beam radiation plus concurrent chemotherapy will be delivered before the extended resection.
• Colostomy-sparing procedures: Mayo offers several procedures that avert the need for a colostomy.
• Minimally invasive surgery

Chemotherapy

Chemotherapy uses drugs to destroy cancer cells. Chemotherapy is usually recommended after surgery if the cancer has spread to the lymph nodes because this approach has been shown to improve survival. It can be used alone for most patients with colon cancer or with radiation therapy for most patients who have rectal cancer. Chemotherapy usually begins about a month after surgery and continues for six months to one year.

Doctors at Mayo Clinic are conducting numerous clinical trials seeking new drugs or new combinations of drugs to prevent the spread or recurrence of cancers. This research was integral to the Food and Drug Administration's approval of a new drug — oxaliplatin — for use in treating metastatic colon and rectal cancer. Prior to the introduction of this drug, the Mayo Clinic-developed regimen of 5-fluorouracil and leucovorin served as a frequent standard to which other chemotherapy regimens were compared.

Radiation Therapy

The health care team may recommend high-energy external beam radiation treatments in combination with chemotherapy before or after surgery. Radiation uses X-rays to kill any cancer cells that remain after surgery or shrink large tumors before an operation so they can be removed more easily. The goal is to destroy or damage the tumor with minimal harm to the surrounding organs or tissues, and therefore involves a planning process called simulation. Radiation fields are designed with sophisticated CT-based systems and 3-D conformal radiation techniques to include the tumor and lymph node sites while excluding as much of the sensitive surrounding tissue as possible. Mayo Clinic radiation oncologists are world leaders in the design and delivery of radiation fields for patients with colon cancer.

Mayo Clinic physicians are also world leaders in radiating tumors when they are exposed during surgery. Done to boost the effective dose of radiation to the tumor, this technique is known as intraoperative radiation therapy (IORT). IORT may be used for patients with locally advanced or locally recurrent colon cancers that attach to or invade other organs or structures or for patients with relapse in nearby lymph nodes.

Biological Therapy

Also called immunotherapy, biological therapy uses the body's immune system to find and destroy cancer cells in the body. Biological therapies may be used to repair, stimulate or enhance the immune system's natural anticancer function. They may be used after surgery and in combination with other treatments. Currently patients receive this treatment by participating in research studies.