A Randomized Controlled Trial

ANAL CANAL CARCINOMA IS AN uncommon malignancy in the United States. Among 1 437 180 new cancer diagnoses projected for the year 2008, approximately 5070 will be new cases of anal canal carcinoma. Anal canal carcinoma has a unique clinical biology that can be distinguished from all other gastrointestinal cancers. It is mostly a local-regional cancer, with a metastatic potential in only 15% of patients, and it is highly sensitive to concurrent chemoradiation, resulting in a cure in 60% of cases. The size of the primary tumor has a direct bearing on the cure rates, and the 5-year survival rates decrease precipitously for tumors larger than 5 cm in diameter. Similarly, the presence of nodal metastases results in a reduction in the cure rate. In addition, with larger primary cancers, the likelihood of lymph node metastases increases. Approximately 25% of newly diagnosed anal canal carcinomas are larger than 5 cm in diameter and clinically node-positive. It has been established that chemoradiationismoreeffectivetherapyforsmaller analcanalcarcinomasthanforlargerones. Thissuggests thatastrategythatcouldreduce theburdenofcancer in theprimary See also Patient Page. Author Affiliations are listed at the end of this article. Corresponding Author: Jaffer A. Ajani, MD, Department of Gastrointestinal Medical Oncology, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd, Mail Stop 426, Houston, TX 77030 (jajani @mdanderson.org). Context Chemoradiation as definitive therapy is the preferred primary therapy for patients with anal canal carcinoma; however, the 5-year disease-free survival rate from concurrent fluorouracil/mitomycin and radiation is only approximately 65%.