Colon Cancer Surgery

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. Therefore, surgery is only one component in the treatment of colon cancer and may be followed by chemotherapy, which aims to eliminate micrometastases.

Surgical procedures that may be used in the treatment of colon cancer include:

• Colonoscopy
• Conventional surgery (open colectomy)
• Laparoscopic 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.

Conventional surgery (open colectomy): Conventional surgery for colon cancer 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 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 outside of the patient's body. 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, also called minimally invasive surgery, allows surgeons to do procedures by making only a few small incisions in the abdomen. A small tube that holds a video camera is inserted into the abdomen, creating a live picture of the inside of the patient's body. This picture is displayed on a television screen so that physicians perform the entire surgery by watching the screen. The cancer is removed through another, slightly larger incision.

Comparison of Conventional and Laparoscopic Surgery

• The short-term advantages of laparoscopic surgery include[1]:
• Faster recovery of bowel function (2 days versus 5 days)
• Decreased time in hospital (40% decrease in days spent in hospital)
• Decreased requirement for painkillers
• Reduction in number of infections, including abdominal, bladder and lung (pneumonia) infections

In the long-term, it is currently unknown whether survival rates after laparoscopic surgery are identical to those of conventional, open surgery. In general, long-term survival rates are similar, although some trials have found lower cancer recurrence rates with conventional surgery.

Conventional and laparoscopic surgery were compared in a clinical trial of 872 patients with stage I colon cancer. Researchers reported that laparoscopic surgery was as safe and effective as conventional surgery. In the short term, 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 conventional surgery.[2] In the long term, cancer recurrence and 3-year survival rates were similar across both groups (table 1).

Table 1. Laparoscopic surgery versus conventional surgery in the treatment of early stage colon cancer

	Laparoscopic surgery	Conventional surgery
Cancer recurrence	16%	18%
3-year survival	86%	85%

A study of 233 patients in the United Kingdom evaluated the long-term survival rates of open resection compared with laparoscopic resection. The overall survival rates were similar in both groups, but traditional, open surgery was associated with a lower cumulative recurrence rate.[3] The results mean that patients undergoing traditional surgery had a lower rate of cancer recurrence compared with the laparoscopic group.

Another recent trial comparing laparoscopic and conventional surgery concluded that recurrence rates were slightly higher in laparoscopic patients, although this difference was not statistically significant. A total of 872 patients underwent either conventional surgery or laparoscopy with overall survival rates of 68% in the conventional surgery group and 67% in the laparoscopic group.[4] Local recurrence rates 2.5% and 0.6% in the laparoscopic group and the conventional group, respectively, but the differences were not statistically significant (meaning they could have happened by chance). Further studies have not found conclusive evidence that laparoscopic surgery leads to higher rates of local recurrence.

When choosing between open and laparoscopic abdominal surgery, patients and their doctors must weigh the potential short-term benefits of laparoscopic surgery with a possible small increase in cancer recurrence that may be associated with laparoscopic resection. Patients may choose based on their own health and the expertise and recommendations of their surgeon.

Surgery for Recurrent or Metastatic Disease

At the time of diagnosis, 10 to 20% of patients with colorectal cancer have cancer that has spread (metastasized) 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, lungs, kidneys, duodenum, pancreas and pelvis (including the bladder). In most patients, metastases occur at multiple sites and are treated with systemic chemotherapy for palliation (relief of symptoms but not cure). 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.

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 may be recommended for some patients with advanced colon cancer to prevent bleeding, obstruction, and symptoms related to the cancer.

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.[5]

Liver metastases: Liver metastases may be treated with a variety of techniques, including hepatic resection, chemotherapy, radiation, cryosurgery and radioablation (the latter two still experimental). Untreated liver metastases are associated with a poor prognosis, so surgery may be worthwhile for patients that are able to tolerate a major procedure. 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. Patients with liver metastases are frequently treated with chemotherapy as well, which can improve overall survival.

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 that has spread to other sites, or isolated liver recurrence after hepatic resection.

Lung metastases: Lung metastases are cancer cells that have spread to the lungs. In some cases, these metastases can be surgically removed with the potential for long-term survival. Patients who are well enough to undergo surgical removal of these tumors and whose tumors are amenable to surgery have 5-year survival rates of up to 44%.[6] If surgery is not an option, because the tumors are too large or the patient is too sick to undergo partial lung resection, chemotherapy may be an option.

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