Oral Topotecan As A Radiosensitizing Agent In Rectal Cancer

Inclusion Criteria: * Patients with histologically confirmed rectal cancer. * Candidates for preoperative radiotherapy. * Primary tumor at least 3cm and clinical stage of T2, T3, or T4 and any N according to the Astler-Coller modification of the Dukes staging system. * Eastern Cooperative Oncology Group (ECOG) performance status less than 2. * Diagnosis of rectal cancer should be no more than 90 days from start of therapy. * Evaluation at the H. Lee Moffitt Cancer Center. * Recovery from prior surgery and life expectancy at least 3 months. Exclusion Criteria: * A primary tumor totally excised. * Recurrent rectal cancer that failed initial treatment. * Exposure to topotecan, infection, immunodeficiencies, conditions of the gastrointestinal (GI) tract which would affect absorption, medication that maintains motility/gastric emptying. * Any concomitant malignancy within the last five years. * Severe medical problems unrelated to the malignancy which would limit compliance with the study. * Patients of child bearing potential. * Not practicing adequate contraception. * Patients who are pregnant or lactating. * Use of an investigational drug within 30 days or 5 half-lives of the first dose.