Overview

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.

Surgical techniques continue to improve, but some patients may still experience recurrence of their cancer, despite the fact that it has been surgically removed. 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.

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 a local excision. A properly performed local excision can be a safe and effective procedure.

Curative Resection: Depending on the stage and spread, some colon cancers can be completely removed. A complete curative resection refers to the surgical removal of the cancer, with the intent to cure the patient. Advances in surgical procedures have led to greater 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 and complete removal of the regional lymph drainage zones. 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%. Hospital mortality was 1.3% for patients who had potentially curative resections. 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 recurrence for stage III patients by 52.4%. These results, from a large center, are achieved through a consistent surgical approach for potentially curable patients.

Hemicolectomy: A hemicolectomy (radical resection) is currently the standard surgical procedure used to remove colon cancer. A hemicolectomy is recommended for cancers at high risk for recurrence, 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 margin of normal bowel and lymph nodes. 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: Extensive surgery can cause serious side effects, including infections, severe pain and prolonged convalescence. As a result, surgeons have worked to develop less invasive surgical techniques for performing hemicolectomy. Recent advances in minimally invasive technology have allowed complex procedures to be performed with the aid of a video camera. 

A laparoscopic procedure has recently been shown to be effective for performing a hemicolectomy, while decreasing the side effects caused by extensive surgery. With this procedure, 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. Before the section of the colon containing the cancer is removed from the body, the incision through which it will be removed is enlarged to allow its passage with minimal contact. This approach is associated with reduced pain and shortened hospitalization. In skilled hands this technique is probably as effective as conventional surgery.

In a recent clinical study, researchers from Texas evaluated the effectiveness of utilizing a laparascopic approach for hemicolectomies. The physicians involved in this study performed laparoscopic hemicolectomies on 50 patients with stage III colorectal cancer. Three years following surgery over 60% of patients had not died from cancer. Five years following surgery, nearly half of the patients were still alive. These patients experienced significantly fewer infections and shortened hospital stays.

These results suggest that laparoscopic hemicolectomies produce results comparable to those of traditional open surgery, while decreasing surgery-related complications in patients with colorectal cancer.

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. Approximately 20% of patients with colon cancer already have distant metastases at the time of diagnosis. Since the 5-year survival rate in this group of patients is only five percent, palliative colon resection is generally recommended to prevent bleeding, obstruction, and symptoms related to local organ invasion.

Surgery for Recurrent or Metastatic Disease

At the time of diagnosis, 15 to 20 % of patients with colorectal cancer have distant metastases. In addition, 30 to 40 % of patients treated by potentially curative resection relapse, with 80% of relapses detected within three years of surgical treatment. 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. Selected patients with isolated sites of metastasis or local recurrence are candidates for salvage surgery.

Liver Metastases: Liver metastases may be treated by liver resection, cryosurgery, regional chemotherapy, or systemic chemotherapy. Because the prognosis for untreated liver metastases is dismal, a strong rationale exists for surgical intervention in otherwise fit patients. 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.

Lung Metastases: Some patients with isolated lung metastases may benefit from resection, depending on the number and location of metastases. The procedure requires that patients have adequate pulmonary function and medical fitness. Complete resection yields a 5-year survival rate of 20 to 44%. When recurrence after resection of pulmonary metastases is limited to the lung, repeat resection is advocated by some physicians.

Pelvic Recurrence: Pelvic recurrence of colorectal cancer has a poor prognosis. Approximately half of all pelvic recurrences are accompanied by distant metastases and are incurable. Surgical resection is sometimes performed in selected patients for the relief of symptoms. For patients with positive resection margins or small areas of gross residual disease, intra-operative radiation therapy can enhance local control.

Strategies to Improve Treatment

The progress that has been made in the treatment of colon cancer has resulted from improved surgical techniques and the development of neoadjuvant and adjuvant treatments in patients with more advanced stages of cancer and participation in clinical trials. Future progress in the treatment of colon cancer will result from continued participation in appropriate clinical trials.

USED WITH PERMISSION OF CANCERCONSULTANTS.COM

Copyright® 1998, last updated 01/01, CancerConsultants.com – All Rights Reserved.

“The information contained above is  general in nature and is not intended as a guide to self-medication by consumers or meant to substitute for advice provided by your own physician or other medical professional. The reader is advised to consult with a physician or other medical professional and to check product information (including packaging inserts) for changes and new information regarding dosage, precautions, and contra indication before administering any drug, herb, supplement, compound, therapy or treatment discussed herein. Neither the editors nor the publisher accepts any responsibility for the accuracy of the information or consequences from the use or misuse of the information contained herein.”

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