Stage I anal cancer was formerly treated with abdominoperineal resection. Current sphincter-sparing therapies include wide local excision for small tumors of the perianal skin or anal margin, or definitive chemoradiation (fluorouracil and mitomycin) for cancers of the anal canal. Salvage chemoradiation therapy (fluorouracil and cisplatin plus a radiation boost) may avoid permanent colostomy in patients with residual tumor following initial nonoperative therapy. Radical resection is reserved for patients with incomplete responses or recurrent disease. Continued surveillance with rectal examination every 3 months for the first 2 years and endoscopy/biopsy when indicated after completion of sphincter-preserving therapy is important.
Note: Separate PDQ summaries on Colorectal Cancer Screening; Colon Cancer Treatment; and Rectal Cancer Treatment are also available.
Factors Associated With Increased Risk of Colorectal Cancer
Excessive alcohol use
Based on solid evidence from observational studies, excessive alcohol use is associated with an increased risk of colorectal cancer (CRC).[1,2,3]
Magnitude of Effect: A pooled analysis of eight cohort studies estimated an adjusted relative risk (RR) of 1.41 (95%...
Small tumors of the perianal skin or anal margin not involving the anal sphincter may be adequately treated with local resection.
As evidenced in RTOG-9208 and RTOG-8314 trials, for example, all other stage I cancers of the anal canal that involve the anal sphincter or are too large for complete local excision are treated with external-beam radiation therapy (EBRT) with or without chemotherapy.[1,3,4,5,6,7,8,9]
Chemotherapy with fluorouracil and mitomycin combined with primary radiation therapy appears to be more effective than radiation therapy alone. The optimal dose of radiation with concurrent chemotherapy has been evaluated, as seen in the RTOG-9208 trial, for example.[11,12]
Selected tumors are also suitable for interstitial radiation therapy.
Radical resection is reserved for residual or recurrent cancer in the anal canal after nonoperative therapy.
Alternately, salvage chemotherapy with fluorouracil and cisplatin combined with a radiation boost may avoid a permanent colostomy in selected patients with small amounts of residual tumor following initial nonoperative therapy.
Interstitial iridium 192 after EBRT may convert some patients with residual disease into complete responders.
Current Clinical Trials
Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with stage I anal cancer. The list of clinical trials can be further narrowed by location, drug, intervention, and other criteria.
General information about clinical trials is also available from the NCI Web site.
Flam M, John M, Pajak TF, et al.: Role of mitomycin in combination with fluorouracil and radiotherapy, and of salvage chemoradiation in the definitive nonsurgical treatment of epidermoid carcinoma of the anal canal: results of a phase III randomized intergroup study. J Clin Oncol 14 (9): 2527-39, 1996.
Enker WE, Heilwell M, Janov AJ, et al.: Improved survival in epidermoid carcinoma of the anus in association with preoperative multidisciplinary therapy. Arch Surg 121 (12): 1386-90, 1986.
Papillon J, Mayer M, Montbarbon JF, et al.: A new approach to the management of epidermoid carcinoma of the anal canal. Cancer 51 (10): 1830-7, 1983.
Cummings B, Keane T, Thomas G, et al.: Results and toxicity of the treatment of anal canal carcinoma by radiation therapy or radiation therapy and chemotherapy. Cancer 54 (10): 2062-8, 1984.
Leichman L, Nigro N, Vaitkevicius VK, et al.: Cancer of the anal canal. Model for preoperative adjuvant combined modality therapy. Am J Med 78 (2): 211-5, 1985.
James RD, Pointon RS, Martin S: Local radiotherapy in the management of squamous carcinoma of the anus. Br J Surg 72 (4): 282-5, 1985.
Sischy B: The use of radiation therapy combined with chemotherapy in the management of squamous cell carcinoma of the anus and marginally resectable adenocarcinoma of the rectum. Int J Radiat Oncol Biol Phys 11 (9): 1587-93, 1985.
Sischy B, Doggett RL, Krall JM, et al.: Definitive irradiation and chemotherapy for radiosensitization in management of anal carcinoma: interim report on Radiation Therapy Oncology Group study no. 8314. J Natl Cancer Inst 81 (11): 850-6, 1989.
Mitchell SE, Mendenhall WM, Zlotecki RA, et al.: Squamous cell carcinoma of the anal canal. Int J Radiat Oncol Biol Phys 49 (4): 1007-13, 2001.
Epidermoid anal cancer: results from the UKCCCR randomised trial of radiotherapy alone versus radiotherapy, 5-fluorouracil, and mitomycin. UKCCCR Anal Cancer Trial Working Party. UK Co-ordinating Committee on Cancer Research. Lancet 348 (9034): 1049-54, 1996.
Fung CY, Willett CG, Efird JT, et al.: Chemoradiotherapy for anal carcinoma: what is the optimal radiation dose? Radiat Oncol Investig 2(3): 152-6, 1994.
John M, Pajak T, Flam M, et al.: Dose Escalation in Chemoradiation for Anal Cancer: Preliminary Results of RTOG 92-08 Cancer J Sci Am 2 (4): 205-11, 1996.
Sandhu AP, Symonds RP, Robertson AG, et al.: Interstitial iridium-192 implantation combined with external radiotherapy in anal cancer: ten years experience. Int J Radiat Oncol Biol Phys 40 (3): 575-81, 1998.