Note: Some citations in the text of this section are followed by a level of evidence. The PDQ editorial boards use a formal ranking system to help the reader judge the strength of evidence linked to the reported results of a therapeutic strategy. (Refer to the PDQ summary on Levels of Evidence for more information.)
The primary treatment for patients with rectal cancer is surgical resection of the primary tumor. Local excision of clinical T1 tumors is an acceptable surgical technique for appropriately selected patients. For all but T1 tumors, a mesorectal excision is the treatment of choice. Very selected patients with T2 tumors may be candidates for local excision. Local failure rates in the range of 4% to 8% following rectal resection with appropriate mesorectal excision (total mesorectal excision [TME] for low/middle rectal tumors and mesorectal excision at least 5 cm below the tumor for high rectal tumors) have been reported.[1,2,3,4,5]
Sigmoidoscopy (SIG-moy-DAH-skuh-pee) enables the physician
to look at the inside of the large intestine from the rectum through the last
part of the colon, called the sigmoid colon. Physicians may use this procedure
to find the cause of diarrhea, abdominal pain, or constipation. They also use
sigmoidoscopy to look for early signs of colorectal cancer in the colon and
rectum. With sigmoidoscopy, the physician can see bleeding, inflammation,
abnormal growths, and ulcers.
For the procedure, you...
The low incidence of local relapse following meticulous mesorectal excision has led some investigators to question the routine use of adjuvant radiation therapy. Because of an increased tendency for first failure in locoregional sites only, the impact of perioperative radiation therapy is greater in rectal cancer than in colon cancer.
Although postoperative therapy for patients with stage II or III rectal cancer remains an acceptable option, neoadjuvant therapy for rectal cancer, using preoperative chemoradiation, is now the preferred option for patients with stage II and III disease.[Level of evidence: 1iA] Benefits of neoadjuvant chemoradiation include tumor regression, downstaging and improvement in resectability, and a higher rate of sphincter preservation and local control. Complete pathologic response rates of 10% to 25% may be achieved with preoperative chemoradiation therapy.[8,9,10,11,12,13,14,15] However, preoperative radiation therapy is associated with increased complications compared to surgery alone; some patients with cancers at a lower risk of local recurrence might be adequately treated with surgery and adjuvant chemotherapy.[16,17,18,19]
Preoperative Chemoradiation Therapy
Multiple phase II studies of preoperative chemoradiation suggested that administering radiation therapy prior to surgery improved the toxicity profile of chemoradiation and enhanced the possibility of sphincter-sparing surgery. The German Rectal Cancer Study Group randomly assigned 823 patients with ultrasound (US)-staged T3/T4 or node-positive rectal cancer to either preoperative chemoradiation therapy or postoperative chemoradiation therapy (50.4 Gy in 28 daily fractions to the tumor and pelvic lymph nodes concurrent with infusional 5-FU 1,000 mg/m2 daily for 5 days during the first and fifth weeks of radiation therapy). All patients received a TME and an additional four cycles of 5-FU-based chemotherapy postoperatively. The overall 5-year survival rates were 76% and 74% for preoperative and postoperative chemoradiation, respectively (P = .80). The 5-year cumulative incidence of local relapse was 6% for patients assigned to preoperative chemoradiation and 13% in the postoperative treatment group (P = .006). Grade 3 or grade 4 acute toxic effects occurred in 27% of the patients in the preoperative treatment group as compared with 40% of the patients in the postoperative treatment group (P = .001); the corresponding rates of long-term toxic effects were 14% and 24%, respectively (P = .01).[Level of evidence: 1iA] There was no difference in the number of patients receiving an abdominoperineal resection in each arm. However, among the 194 patients with tumors that were determined by the surgeon before randomization to require an abdominoperineal excision, a statistically significant increase in sphincter preservation was achieved among patients who received preoperative chemoradiation (P = .004).