Surgical Treatment of Cancer of the Colon or Rectum
Cancer of the colon and rectum (or colorectal cancer) is the third most common form of cancer and is the second leading cause of cancer mortality in the United States.
Although the majority of colorectal cancers have no identifiable underlying cause, they are thought to arise from a series of genetic events that result in precursor lesions such as polyps (see Management of Colonic Polyps and Adenomas) leading to the formation of cancer. Nearly 20% of patients with colorectal cancer have a positive family history of at least one first or second degree relative with colorectal cancer. Five to ten percent have a known inherited predisposition to develop this disease, with familial adenomatous polyposis (FAP) and hereditary nonpolyposis colorectal cancer (HNPCC) being the two major syndromes. Patients with FAP develop hundreds to thousands of colorectal adenomatous polyps during the second or third decade of life. If untreated, virtually all patients will develop colorectal carcinoma by the age of 45. Patients with HNPCC have a high lifetime risk of developing colorectal cancer and typically are characterized by an early onset of carcinoma (average age 45 years) and a tendency to develop cancers in the proximal colon as well as synchronous and metachronous cancers. Other conditions that predispose to colorectal cancer include ulcerative colitis, Crohn's colitis, schistosomal colitis, exposure to radiation, and non-familial colorectal adenomatous polyps.
Symptoms and Diagnosis
Screening measures used to detect early cancers or premalignant polyps in asymptomatic persons include digital rectal examination, fecal occult blood testing, endoscopy and radiographic imaging,. Colorectal cancer may be asymptomatic. When present symptoms may include anemia, rectal bleeding and change in bowel habits, or tenesmus (painful incomplete fecal evacuation) depending on the location and extent of the tumor. Systemic manifestations such as weight loss and fatigue due to chronic anemia suggest advanced disease. Obstruction, perforation, and acute bleeding may occur as complications of colon cancer.
Physical examination may reveal a palpable abdominal or rectal mass. Abdominal distention suggests high-grade rectal or colonic obstruction, and rarely the presence of malignant ascites.
The entire colon should be examined preoperatively by colonoscopy or barium enema if cancer of the colon or rectum is suspected, unless contraindicated by colonic obstruction or other circumstances. With colonoscopy, cancers can be seen and biopsied, and synchronous neoplastic polyps can be removed if not contained within the segment of resected bowel.
Metastases can be detected by chest X-ray and suggested based on elevation of carcinoembryonic antigen (CEA) level or liver function tests. CEA is not an accurate diagnostic test for colorectal cancer in a curable stage, but may be helpful in detecting recurrence after curative resection. Ultrasound, computed tomography (CT) or magnetic resonance imaging (MRI) scans of the abdomen may be used to search for hepatic metastases. CT or MRI scans of the pelvis or endorectal ultrasonography in patients with rectal cancer may assist in tumor staging and treatment planning.
Preoperative histological confirmation is not required if the primary lesion in the colon or rectum has the characteristics of a cancer not under consideration for preoperative chemoradiation treatment. For suspected liver metastasis, histological confirmation can usually be obtained at the time of surgery.
Surgical removal is the preferred treatment for colorectal cancer. Surgical treatment is indicated in nearly all patients with newly diagnosed cancer of the large intestine unless survival is unlikely or life expectancy is very short due to advanced cancer or other diseases. Even in the presence of metastases, palliative surgical resection of the primary tumor may be advisable to prevent further bleeding and impending obstruction.
Operative treatment for colorectal cancer consists of wide surgical resection of the involved bowel segment and regional lymphatic drainage. Primary anastomosis of a prepared bowel is possible in elective cases. Laparoscopic colectomy for colon neoplasia has been shown to be equivalent to open colectomy when performed by experienced surgeons.
Operative treatment of rectal cancer includes en bloc resection of the rectum as an intact unit with its lymphovascular drainage contained within the fascia propria of the mesorectum using sharp dissection techniques (Total Mesorectal Excision). Preservation of the anal sphincters and avoidance of a permanent colostomy is preferred in rectal cancer if eradication of the cancer with adequate margins is also achieved. A temporary diverting colostomy may be necessary depending on intraoperative findings. Transanal local excision of rectal cancer may be appropriate and curative for selected patients with small, early stage, and accessible tumors that exhibit favorable histologic features. Palliative treatment for unresectable rectal cancers includes fulguration, laser photocoagulation, radiation therapy, and endostenting.
Radiation therapy and chemotherapy are used for advanced disease and in conjunction with surgical resection. While radiation therapy has little role in management of colon cancer, it is an important treatment modality for rectal cancer. Bulky rectal cancers may be treated preoperatively to improve resectability. For stage II (invasion through the muscularis propria of the rectal wall) or stage III rectal cancer (metastases to regional lymph nodes), radiation therapy is a useful preoperative or postoperative adjunct and is also used in combination with chemotherapy.
Patients with colon cancer and lymph node metastases (Stage III), as well as selected patients without lymph node metastases (Stage II) should be considered for postoperative adjuvant chemotherapy.
Postoperative complications of resection for colorectal cancer generally involve infections related to the bacterial flora of the large bowel. The most common postoperative complication is wound infection (2-4% in elective cases), which is minimized by mechanical and antibiotic bowel preparation and prophylactic intravenous antibiotics. Other risks include bleeding, anastomotic leakage, pelvic abscess, damage to neighboring organs (such as the spleen or ureter), sexual and urinary dysfunction, and wound dehiscence.
The length of hospitalization is generally determined by the return of normal bowel function and in most cases is usually within one week. The resumption of normalized physical activity is affected by the mode of surgery, either laparoscopic or open approach. Elderly or debilitated patients may have a longer recovery period.
Bowel movements following operation may either be normal or may be more loose and frequent, depending upon the portion and length of bowel removed. While these changes are rarely severe, disordered bowel habits after anterior resection with a very low anastomosis can be quite troublesome. Most patients with colostomies adjust well with the help of support groups and family. Long-term dietary restrictions are generally not necessary.
The clinicopathologic stage of disease is the most important determinant of survival after surgical resection. Five-year survival rates vary from 90% for tumors confined to the mucosa and submucosa to less than 5% for those with distant metastases. About 70% of these patients can be cured by operation.
Follow-up after curative resection of colorectal cancer involves measurement of serum CEA levels every 3-6 months for the first 3 years, colonoscopy one year after surgery and then every three years. Based on clinical indications, radiographic imaging such as chest X-ray, ultrasound, CT and/or MRI scan may also be indicated to evaluate for regional recurrence or metastatic disease. Whole body FDG-PET scanning is a new modality that may be useful in selected circumstances for identifying metastatic disease. Patients with recurrent colon or rectal cancer who do not have evidence of distant disease may be candidates for surgical resection with or without adjuvant radiation therapy. Localized hepatic or pulmonary metastases detected during follow up should be evaluated for possible resection. If one or a few lesions can be completely resected, survival is significantly prolonged.
Qualifications for Performing Operations on the Colon
The qualifications of a surgeon performing any operative procedure should be based on training (education), experience, and outcomes. At a minimum, surgeons who are certified or eligible for certification by the American Board of Surgery or the Royal College of Physicians and Surgeons of Canada, or their equivalent should perform colonoscopy and/or colectomy. These surgeons have successfully completed at least 5 years of surgical training after medical school graduation and are qualified to perform operations on the colon. When performing laparoscopic colon surgery, it is highly desirable that the surgeon has advanced laparoscopic skills. The level of training in advanced laparoscopic techniques necessary to conduct minimally invasive surgery of the colon is important to assess.
The Clinical Outcomes of Surgical Therapy Study Group (COST): A comparison of laparoscopically assisted and open colectomy for colon cancer. NEJM 2004;350:2050.
Chang GJ, Shelton A, Welton ML. Large Intestine. In: Current Surgical Diagnosis and Treatment, 12th edition (Way LW, Doherty GM, eds). Lange Medial Books/McGraw-Hill. 2004.
Kapiteijn E et al: Preoperative radiotherapy combined with total mesorectal excision for resectable rectal cancer. Dutch ColoRectal Cancer Group. N Engl J Med 2001;345:638.
Pfister DG, Benson AB, and Somerfield MR. Surveillance Strategies after Curative Treatment of Colorectal Cancer. N Engl J Med 2004;350:2375-2382.
Saltz LB and Minsky B: Adjuvant therapy of cancers of the colon and rectum. Surg Clin North Am. 2002;82:1035-1058.
Winawer SJ, Zauber AG: Colonoscopic polypectomy and the incidence of colorectal cancer. Gut 2001;48:753.
colorectal cancer, colorectal neoplasms, colectomy, colostomy, familial, proctocolectomy, proctectomy, laparoscopy, guideline, patient
Board Approved 10/8/96
Board Approved 5/14/05
SSAT Patient Care Committee Guidelines
These patient care guidelines were written for the primary care physicians on a variety of digestive diseases to assist on when to refer the patient for surgical consultation.
Their goal is to guide PRIMARY CARE physicians to the appropriate utilization of surgical procedures on the alimentary tract or related organs and they are based on critical review of the literature and expert opinion. Both of the latter sources of information result in a consensus that is recorded in the form of these Guidelines. The consensus addressses the range of acceptable clinical practice and should not be construed as a standard of care. These Guidelines require periodic revision to ensure that clinicians utilize procedures appropriately but the reader must realize that clinical judgment may justify a course of action outside of the recommendations contained herein.
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