Organ Preservation Program Using Short-Course Radiation & FOLFOXIRI in Rectal Cancer

Inclusion Criteria: * 1\. Pathologically (histologically or cytologically) proven diagnosis of adenocarcinoma of rectum requiring total mesorectal excision as deemed by multidisciplinary evaluation * 2.At least 18 years of age * 3.For women of childbearing potential or who are not postmenopausal (see Appendix B for Definition of Menopausal Status), a negative urine or serum pregnancy test must be done. Also, women of childbearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) for the duration of study participation and for up to 4 weeks following the study. Should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately. * 4.ECOG 0, 1, or 2 * 5.Ability to understand and the willingness to personally sign the written IRB approved informed consent document. * 6.Patients must have acceptable organ and marrow function as defined below: * Absolute neutrophil count (ANC) \>1,500/uL * Hg \> 8.0 g/dL; if blood transfusion is performed for achieving adequate hemoglobin level, the level should stay above goal for at least 1 week after transfusion * Platelets \>100,000/uL * Total bilirubin \<1.5X normal institutional limits * aspartate aminotransferase (AST) (SGOT) / alanine aminotransferase (ALT)(SGPT) \< 3X upper limit of normal * Creatinine \<1.5X upper limit of normal or creatinine clearance (CrCL)\>50 by Cockcroft-Gaul…