Sphincter preservation in rectal cancer. External-beam radiation therapy alone.
Wong CS. Brierley JD.
Princess Margaret Hospital, University of Toronto, Toronto, Ontario.
Surgery with or without adjuvant radiation therapy and chemotherapy is the standard treatment for patients with resectable rectal carcinoma. Many patients, however, are medically unfit or simply refuse surgery that could result in a colostomy. This article reviews the results of external-beam radiation therapy alone for selected patients with rectal carcinoma and its role in preserving anorectal function. For patients with mobile tumors, a 5-year survival and local relapse-free rate of 30% and 25%, respectively, can be expected after external-beam radiation therapy alone, and 60% remain colostomy free. Results of radiation therapy alone in patients with fixed or unresectable tumors are poor. Although more than a third of patients remain colostomy-free, only 5% of patients survive 5 years. In patients with mobile rectal carcinomas that are not amenable to sphincter-preserving surgery, who are unfit medically for radical surgery, or who refuse a colostomy, external-beam radiation therapy offers the reality of sphincter preservation and the possibility of long-term tumor control.
Sphincter preservation in rectal cancer. Endocavitary radiation therapy.
Gerard JP. Romestaing P. Ardiet JM. Mornex F.
Service de Radioth-erapie-Oncologie, Centre Hopitalier Lyon Sud, Pierre Benite Cedex, France.
Endocavitary radiation therapy (Endo RT) is performed mainly with a contact x-ray tube. Interstitial brachytherapy is a supplementary method to boost the tumor bed. Only strictly selected patients can be treated for cure by Endo RT. More than 1,000 patients have been treated in Europe and North America since 1950. In T1 N0 adenocarcinoma, the primary local control rate is close to 90%. The overall 5-year survival is between 60% and 90% depending on patient selection. Careful follow-up is necessary because the majority of local failures can be salvaged, usually by radical surgery. The main advantages of Endo RT are a fully ambulatory and simple treatment that can be applied even in frail or elderly inoperable patients, a low risk of complications, and an inexpensive treatment. Results show it is possible to perform curative treatment in patients with more advanced rectal carcinoma. With the combination of external-beam radiation therapy and Endo RT in stage T2-3 N0-1 tumors, the primary local control rate is around 70%, and the incidence of severe radiation toxicity is less than 5%. Overall 5-year survival is between 50% and 70%. Endo RT can also be used as an adjuvant treatment after local excision, in the treatment of villous adenomas, and for palliation of advanced inoperable tumors.
Sphincter preservation in rectal cancer. Local excision followed by postoperative radiation therapy.
Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA 02114, USA.
The management of distal rectal cancer is in evolution. Although abdominoperineal resection has been long regarded as the definitive treatment of distal rectal cancer, it is associated with significant morbidity--loss of anorectal function with a permanent colostomy and a high incidence of sexual and genitourinary dysfunction. To overcome these limitations, innovative efforts are underway studying the feasibility and efficacy of a variety of sphincter-preserving operations, usually in combination with radiation therapy and chemotherapy. Local excision procedures with adjuvant therapy represent one such treatment strategy that attempts to optimize local control and survival with preservation of sphincter integrity. This article summarizes the current role of local excision and postoperative irradiation and chemotherapy for patients with carcinoma of the rectum.
Sphincter preservation in rectal cancer. Preoperative radiation therapy followed by low anterior resection with coloanal anastomosis.
Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
The advantage of preoperative therapy in patients with clinically resectable transmural rectal cancer is to increase sphincter preservation while obtaining a high likelihood of local control. In patients who undergo a prospective clinical assessment and are declared to require an abdominoperineal resection, preoperative radiation therapy, either alone or when combined with chemotherapy, allows approximately 80% of patients to undergo a low anterior resection with or without colo anal anastomosis. The majority have good-to-excellent sphincter function. This conservative approach may be an alternative to an abdominoperineal resection in selected patients.
Sphincter preservation in rectal cancer. Preoperative radiation therapy followed by local excision.
Ahmad NR. Nagle DA.
Department of Radiation Oncology (Ahmad) and Division of Colorectal Surgery (Nagle), Jefferson Medical College of Thomas Jefferson University, Philadelphia, PA 19007, USA.
Radiation therapy followed by local excision results in local control rates that appear comparable to those of local excision alone (in highly selected patients) or local excision followed by adjuvant radiation therapy. A significant drawback of this approach, however, is the potential loss of important histological information, such as risk of lymph node metastasis, depth of tumor penetration, and presence of lymphatic or vascular invasion. Radiation therapy followed by local excision may be an option for treatment of more advanced T3 rectal cancers in patients who either refuse radical surgery or are medically unfit. The available data in the literature do not support the routine use of local excision after radiation therapy in otherwise healthy patients with locally advanced rectal cancer.
Sphincter preservation in rectal cancer. Surgical considerations for local excision.
Johnson DE. Hoffman JP.
Department of Surgical Oncology, Fox Chase Cancer Center, Philadelphia, PA, USA.
The principles involved in selecting patients for local excision of rectal cancers, as well as the various techniques and principles for local resection, are detailed in this article. The assessment of the current role of this technique awaits further maturation of data from phase II clinical trials. The addition of chemotherapy and radiation therapy may allow treatment of more advanced rectal cancers by these techniques.
Sphincter preservation in rectal cancer. Technical considerations for coloanal anastomosis and J-pouch.
Paty PB. Cohen AM.
Department of Surgery, Cornell University Medical Center, New York, NY, USA.
Most patients with midrectal cancer undergo a sphincter-preserving operation using modern bowel stapling techniques. In patients with bulky tumors or unfavorable pelvic anatomy, however, abdominoperineal resection with permanent colostomy may be performed for technical reasons, not based on oncologic clearance needs. In addition, low-lying tumors treated initially with preoperative chemoradiation are often downstaged, increasing the opportunity for restorative procedures. Treatment by total proctectomy and peranal sutured coloanal reconstruction fulfills the need for adequate oncologic clearance and satisfactory bowel function. Sharp pelvic dissection with removal of the entire rectal mesentery, adequate mobilization of the left colon, and precise anastomotic technique are required for optimal results. Creation of a colon J-pouch increases the capacity of the reconstructed rectum and greatly reduces the time required for functional adaptation in the postoperative period. Although irregular evacuation and other minor problems can persist, permanent colostomy is avoided, and patient satisfaction is high. For cancers of the middle and distal rectum, total proctectomy with coloanal reconstruction is an important treatment option that can improve quality of life without compromising cancer treatment.
Clinical and molecular prognostic factors in sphincter-preserving surgery for rectal cancer.
Jessup JM. Loda M. Bleday R.
Department of Surgery, Israel Deaconess Medical Center, Boston, MA 02215, USA.
As many as a third of patients with rectal cancers may be candidates for sphincter preservation surgery. The goal of the conservative management of adenocarcinoma of the distal rectum is to preserve rectal sphincter function without sacrificing local tumor control. To achieve this goal, a combined modality approach is necessary because multimodality therapy for more advanced disease has improved both local control and survival. Candidates for local excision are those with adenocarcinomas with a maximal diameter of less than 4 cm, mobile, and not poorly differentiated or mucinous and within 10 cm of the anal verge--usually within 6 cm. These criteria should be defined objectively by biopsy combined with state-of-the-art endorectal imaging. Newer molecular markers that are associated with prognosis and response to therapy may also be important for assessing prognosis, probability of local recurrence, and whether conservative treatment is appropriate. Patients with T0-3 N0 lesions meeting these standard clinicopathologic criteria have been treated successfully with wide local excision combined with chemotherapy and radiotherapy. Patients with larger or more advanced lesions may undergo low anterior resection with coloanal anastomosis. After resection, radiotherapy to at least 45 to 50 Gy is delivered to the pelvis and tumor bed often with concomitant chemotherapy. The overall rate of local failure in prospective single-institution trials in which local excision is performed with postoperative chemoradiotherapy has been 5% for T1 lesions, 7% for T2 lesions and 24% for T3 lesions. Although single-institution studies have supported the concept of conservative therapy, the safety and efficacy of this approach must still be confirmed in a multicenter, prospective trial, such as that underway in several of the cooperative oncology groups, before it may be considered a standard of practice.