Capecitabine + Irinotecan Followed by Combined Modality Capecitabine and Radiation in Locally Advanced Rectal Cancer

OUTLINE: This is a multi-center study. Biopsy per EUS * Irinotecan 200 mg/m2 IV, day 1 * Capecitabine 1000\* mg/m2 PO BID day 1-14 Repeat every three weeks for two cycles\* For calculated creatinine clearance of 30-50 mL/min or patients \> 70years old, capecitabine starting dose is 825 mg/m2 PO BID Beginning at week 7 or following recovery from chemotherapy: * Pelvic XRT 45 Gy/1.8 Gy/fx/qd+5.4 Gy/1.8 Gy/fx/qd for T3+9 Gy/1.8 Gy/fx/qd for T4 * Capecitabine 825\* mg/m2 PO BID, 5 days/week, throughout XRT\* For calculated creatinine clearance of 30-50 mL/min or patients \> 70years old, capecitabine starting dose is 650 mg/m2 PO BID * Surgery within 8weeks following chemoradiotherapy * Adjuvant Chemotherapy at investigator's discretion ECOG performance status 0 or 1 Hematopoietic:· * ANC count \>1,500 mm3· * Platelets \> 100,000/mm3· * Hemoglobin \> 9g/dL * Prothrombin time (PT)/INR or PTT \< 1.25 times upper limit of normal; Hepatic:· * Bilirubin \<1.5 times upper limit of normal * Alanine Transaminase (ALT) or Aspartate Transaminase (AST) \<2.5 times the upper limit of normal Renal:· * Adequate renal function by calculated creatinine clearance \> 30 mL/min (by Cockroft and Gault) Cardiovascular:· * No congestive heart failure requiring therapy or NYHA class II or greater or active angina or known myocardial infarction within 12 months prior to study