Colon removal or colectomy

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Monday, 26 January 2009 14:11

In patients with potentially curable colon cancer, a properly performed surgical operation is essential for optimal results. In the majority of such cases, operative intervention involves a resection (removal) of the primary cancer and regional lymph nodes, along with the removal of sections on both sides of the normal bowel. There are several different types of surgical procedures used in the treatment and management of colon cancer. The size and spread of the cancer helps determine the appropriate procedure to use. Some patients may still experience a recurrence of their cancer, despite undergoing surgical removal. It is important to realize that some patients with colon cancer already have small amounts of cancer that have spread outside the colon and were not removed by surgery. Undetectable areas of cancer outside the colon are referred to as micrometastases and cannot be detected with any of the currently available tests. The presence of these microscopic areas of cancer causes the relapses that occur after treatment with surgery alone. Surgery is only one component in the treatment of colon cancer and is usually followed by chemotherapy to cleanse the body of micrometastases. Surgical procedures that may be used in the treatment of colon cancer include: Colonoscopy Curative surgery (resection) Conventional surgery (hemicolectomy) Laparascopic surgery Palliative surgery Surgery for lung and liver metastases Primary Surgical Management of Colon Cancer Colonoscopy: Some cancers appear to be less aggressive and are limited to the head of a single polyp. These cancers present no evidence of spread to the lymph system, blood vessels and nervous system, and therefore, may be removed with a local excision. In an effort to avoid unnecessary invasive surgery, these cancers can be treated with a colonoscopy. During a colonoscopy, a long flexible tube that is attached to a camera is inserted through the rectum and is used both to view the internal lining of the colon and to perform the removal of a small cancer (local excision.) A properly performed local excision can be a safe and effective procedure. Curative surgery (resection): Depending on the stage and spread, some colon cancers can be completely removed. A complete curative resection refers to the complete surgical removal of the cancer, with the intent to cure the patient. Advances in surgical procedures have led to greater treatment success and higher cure rates. In the United States, overall colon cancer mortality has declined over the past 20 years. For patients undergoing a "complete" curative resection, the overall 5-year survival rate is between 55 and 75 %. In one clinical study, 696 patients with colon cancer were treated with surgery. Radical surgery for localized cancers was consistently performed, including wide resection margins (healthy tissue surrounding the cancer) and complete removal of the regional lymph nodes. The overall cancer resection rate was 99.3% and complete cancer removal was possible for 84.8% of all patients. The overall post-operative hospital mortality rate was 3.2%. For patients with stage I-III colon cancer where the cancer could be totally removed, the 10-year cure rate was 78.8%. The delivery of adjuvant chemotherapy following surgical resection further reduced cancer recurrences for stage III patients by 52.4%. Conventional surgery (hemicolectomy): Conventional surgery involves an invasive procedure to remove cancer in the colon. This procedure is also called a hemicolectomy and is currently the standard surgical procedure used to remove colon cancer. A hemicolectomy is recommended for cancers that are likely to recur (return), which is the case for most cancers of the colon. A hemicolectomy is an invasive surgery that requires surgeons to create a large opening in the abdomen in order to reach the cancer. This procedure involves the removal of the cancer, along with a some of the normal bowel and lymph nodes that were surrounding the cancer. After this removal, the two cut ends of the colon are sewn together. In some instances, a temporary colostomy is created and the two ends of the colon are reconnected at a later time. A colostomy is an opening where the large intestine is attached to the abdominal wall and allows passage of stool into a replaceable bag. In some instances, when the cancer cannot be completely removed, the two ends are not re-sewn together and the patient has a permanent colostomy. Laparoscopic surgery: Laparoscopic surgery involves the use of a video camera to create a live picture of the inside of the patient’s body, allowing surgeons do procedures by making only a few small incisions, rather than a very larger opening in the abdomen. Extensive surgery can cause serious side effects, including infections, severe pain and a long recovery period. Laparoscopic surgery is a less invasive surgical technique and has been shown to be as effective as standard surgery with fewer side effects. In laparoscopic surgery, a few one-centimeter incisions are made in the patient’s abdomen. Then, a very small tube that holds a video camera can be inserted through the incisions, creating a live picture of the inside of the patient’s body. This picture is continually displayed on a television screen so that physicians can perform the entire surgery by watching the screen. The cancer is removed through a larger incision. This type of surgery is associated with reduced pain and shortened hospitalization. In skilled hands this technique is probably as effective as conventional surgery. When laparascopic surgery and conventional surgery were compared in a clinical trial with patients who had stage I colon cancer, researchers reported that laparoscopic surgery to be as safe and effective as standard surgery. This trial 872 patients diagnosed with early colon cancer. Approximately half of the patients underwent laparoscopic surgery to remove their cancer, and the other half underwent conventional surgery. Approximately the same number of patients in each group lived 3 years or more and the number of patients that had a return of their cancer was similar (see table 1). Patients who underwent laparoscopic surgery used less pain medication and their stay in the hospital was reduced by an average of one day compared to the patients who underwent standard surgery. Palliative surgery: Palliative treatment is treatment that is intended to relieve symptoms, such as pain, but is not expected to cure disease. The main purpose of palliative treatment is to improve the patient's quality of life. Palliative surgery to remove a portion of the colon is generally recommended to prevent bleeding, obstruction, and symptoms related to the cancer. Surgery for Recurrent or Metastatic Disease At the time of diagnosis, 15 to 20% of patients with colorectal cancer have cancer that has spread (metastases) to areas of the body that are distant from the area where the cancer started. The most common sites of metastasis and relapse are the liver, the peritoneal cavity, the pelvis, the retroperitoneum and the lungs. In most patients, metastases occur at multiple sites and are treated with systemic chemotherapy for palliation. Some patients who have cancer that has spread to a single area or recurrence near the original site are candidates for surgery to remove the metastases. Surgery for Liver and Lung Metastases Colon cancer commonly spreads (metastasizes) to the liver and lungs. Physicians from the Mayo Clinic have determined that select patients with colon cancer that has metastasized to the liver and lungs may have an increased chance for long-term survival with surgical removal of these metastases. This trial involved 58 patients with colon cancer who had metastases to both the liver and lungs, but no relapse of their cancer at the original site. All patients underwent the surgical removal of their metastases at the Mayo Institution between 1980 and 1988. There were no deaths during surgery. Five years following surgery, 55% of patients remained cancer-free. The patients that responded best to treatment did not have thoracic lymph node involvement and did not have an elevated carcinoembryonic antigen, which is a type of protein found on the surface of cancer cells. Liver metastases: Liver metastases may be treated with a variety of techniques. However, because the liver metastases that are left untreated is associated with a poor prognosis, the risks associated with surgery may be worthwhile for patients that are able to undergo major surgery. Hepatic resection for liver metastasis is associated with an average survival of 20 to 40 months and a five-year survival rate of 25 to 48%. Long-term disease-free survival has been reported in 12 to 19% of cases. The patients who experience optimum survival are those who have a prolonged disease-free interval after resection of the primary cancer, fewer than four metastases, limited liver involvement and the absence of symptoms. The presence of cancer outside the liver, whether removed or not, is associated with poor survival and is a relative contraindication to surgery. In carefully selected cases, there has been an observed benefit of repeat resection for liver-only recurrences. The primary advantage of cryosurgery (destruction of tissue by the freeze-thaw process) over resection is the preservation of normal liver cells. It has been used to treat both resectable and unresectable liver metastases, with local control rates of 14 to 30%. Although cryosurgery remains an investigational therapy, it may prove useful in treating colorectal liver metastases in patients with cirrhosis, cancer spread to other sites or isolated liver recurrence after hepatic resection.

Last Updated on Wednesday, 25 February 2009 18:00