Primary Outcome Measures:
The objectives of this study are three-fold. First, we would like to learn and compare the doses of radiation received by the tumor and the normal tissues in anal cancer patients treated with IMRT, and in those treated with conventional radiotherapy. Second, we wish to compare the acute effects of radiation treatment in both groups of patients. Our third objective is to evaluate the late effects of radiation treatment in both groups of patients. The first two objectives will be studied using a retrospective analysis of patients with anal cancer treated at Stanford University Medical Center. The third objective will require these patients to complete and return three quality of life questionnaires.